U.S. patent application number 15/346367 was filed with the patent office on 2017-06-01 for compositions of lean nox trap (lnt) systems and methods of making and using same.
The applicant listed for this patent is SDCmaterials, Inc.. Invention is credited to Maximilian A. BIBERGER, Bryant KEARL, David LEAMON, Xiwang QI, Qinghua YIN.
Application Number | 20170151552 15/346367 |
Document ID | / |
Family ID | 52993516 |
Filed Date | 2017-06-01 |
United States Patent
Application |
20170151552 |
Kind Code |
A1 |
KEARL; Bryant ; et
al. |
June 1, 2017 |
COMPOSITIONS OF LEAN NOX TRAP (LNT) SYSTEMS AND METHODS OF MAKING
AND USING SAME
Abstract
The present disclosure relates to a substrate comprising
nanoparticle catalysts and NO.sub.x storage materials for treatment
of gases, and washcoats for use in preparing such a substrate. Also
provided are methods of preparation of the nanoparticle catalysts
and NO.sub.x storage materials, as well as methods of preparation
of the substrate comprising the nanoparticle catalysts and NO.sub.x
storage materials. More specifically, the present disclosure
relates to a coated substrate comprising nanoparticle catalysts and
NO.sub.x storage materials for lean NO.sub.x trap (LNT) systems,
useful in the treatment of exhaust gases.
Inventors: |
KEARL; Bryant; (Phoenix,
AZ) ; YIN; Qinghua; (Tempe, AZ) ; QI;
Xiwang; (Scottsdale, AZ) ; LEAMON; David;
(Gilbert, AZ) ; BIBERGER; Maximilian A.;
(Scottsdale, AZ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SDCmaterials, Inc. |
Tempe |
AZ |
US |
|
|
Family ID: |
52993516 |
Appl. No.: |
15/346367 |
Filed: |
November 8, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
14521334 |
Oct 22, 2014 |
9517448 |
|
|
15346367 |
|
|
|
|
61894346 |
Oct 22, 2013 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B01J 23/464 20130101;
F01N 2370/02 20130101; B01D 53/9431 20130101; B01D 2255/20776
20130101; B01D 2255/9202 20130101; B01J 35/006 20130101; F01N
2570/14 20130101; B01J 23/02 20130101; B01J 23/44 20130101; B01J
23/63 20130101; B01D 2255/20738 20130101; B01J 37/0244 20130101;
B01J 35/04 20130101; B01J 35/0006 20130101; B01D 2255/2061
20130101; B01J 37/0236 20130101; B01D 2255/1021 20130101; B01D
2255/2063 20130101; B01D 2255/1025 20130101; B01J 35/0013 20130101;
B01D 2255/1023 20130101; B01D 2255/40 20130101; B01D 2255/20792
20130101; F01N 3/10 20130101; B01D 2255/407 20130101; B01D 53/9422
20130101; B01D 2255/104 20130101; B01J 37/0248 20130101; B01D
2255/20715 20130101; B01J 37/349 20130101; B01D 2255/2065 20130101;
B01J 23/10 20130101; B01D 2255/91 20130101; B01J 37/04 20130101;
B01D 2255/908 20130101 |
International
Class: |
B01J 23/46 20060101
B01J023/46; B01J 23/10 20060101 B01J023/10; B01J 23/02 20060101
B01J023/02; F01N 3/10 20060101 F01N003/10; B01J 35/04 20060101
B01J035/04; B01J 37/04 20060101 B01J037/04; B01J 37/02 20060101
B01J037/02; B01D 53/94 20060101 B01D053/94; B01J 23/44 20060101
B01J023/44; B01J 35/00 20060101 B01J035/00 |
Claims
1-94. (canceled)
95. A method of treating an exhaust gas, comprising: flowing the
exhaust gas through a conduit; and contacting a coated substrate
with the exhaust gas, the coated substrate comprising: a substrate;
a washcoat layer comprising oxidative catalytically active
micron-particles, the oxidative catalytically active
micron-particles comprising oxidative composite nanoparticles
bonded to a first micron-sized carrier particle, the oxidative
composite nanoparticles comprising a first support nanoparticle and
an oxidative catalytic nanoparticle; a washcoat layer comprising
reductive catalytically active micron-particles, the reductive
catalytically active micron-particles comprising reductive
composite nanoparticles bonded to a second micron-sized carrier
particle, the reductive composite nanoparticles comprising a second
support nanoparticle and a reductive catalytic nanoparticle; and a
washcoat layer comprising NO.sub.x trapping particles, the NO.sub.x
trapping particles comprising a micron-sized cerium
oxide-containing material.
96. The method of claim 95, wherein the micron-sized cerium
oxide-containing material comprises cerium oxide, cerium-zirconium
oxide, cerium-lanthanum oxide, cerium-yttrium oxide,
cerium-zirconium-lanthanum oxide, cerium-zirconium-yttrium oxide,
cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide.
97. The method of claim 96, wherein the micron-sized cerium
oxide-containing material comprises cerium-zirconium-lanthanum
oxide or cerium-zirconium-lanthanum-yttrium oxide.
98. The method of claim 95, wherein the washcoat layer comprising
reductive catalytically active micron-particles is located closer
to the substrate than the washcoat layer comprising oxidative
catalytically active micron-particles.
99. The method of claim 98, wherein the washcoat layer comprising
oxidative catalytically active micron-particles is located closer
to the substrate than the washcoat layer comprising NO.sub.x
trapping particles.
100. The method claim of 95, wherein the NO.sub.x trapping
particles further comprise barium oxide impregnated in the
micron-sized cerium oxide-containing material.
101. The coated substrate of claim 100, wherein the barium oxide is
impregnated in the micron-sized cerium oxide or the micron-sized
cerium oxide-containing material by wet chemistry.
102. The method of claim 95, wherein the NO.sub.x trapping
particles further comprise platinum or palladium impregnated in the
micron-sized cerium oxide-containing material.
103. The method of claim 102, wherein the platinum or palladium is
plasma-generated.
104. The method of claim 102, wherein the platinum or palladium is
impregnated in the micron-sized cerium oxide-containing material by
wet chemistry.
105. The method of claim 95, wherein the NO.sub.x trapping
particles further comprise the perovskite FeBaO.sub.3 impregnated
in the micron-sized cerium oxide-containing material.
106. The method of claim 95, wherein the NO.sub.x trapping
particles further comprise metal oxides selected from the group
consisting of samarium, zinc, copper, iron, and silver oxides
impregnated in the micron-sized cerium oxide-containing
material.
107. The method of claim 95, wherein the washcoat layer comprising
NO.sub.x trapping particles further comprises micron-sized aluminum
oxide particles.
108. The method of claim 95, wherein the oxidative catalytically
active micron-particles comprise a material selected from the group
consisting of platinum, palladium, and a platinum-palladium
alloy.
109. The method of claim 95, wherein the NO.sub.x trapping
particles further comprise zirconium oxide.
110. The method of claim 95, wherein the first micron-sized carrier
particle or the first support nanoparticle comprises aluminum
oxide.
111. The method of claim 95, wherein the second micron-sized
carrier particle or the second support nanoparticle comprises
cerium oxide.
112. The method of claim 95, wherein the washcoat layer comprising
the oxidative catalytically active micron-particles or the washcoat
layer comprising reductive catalytically active micron-particles
further comprises filler particles or boehmite particles; wherein
the filler particles are metal oxide particles.
113. The method of claim 95, wherein the conduit is configured to
receive the exhaust gas from an engine configured to alternatively
operate in lean-burn or rich-burn.
114. The method of claim 95, wherein the coated substrate is housed
within a catalytic converter configured to receive the exhaust
gas.
115. A method of treating an exhaust gas, comprising: flowing the
exhaust gas through a conduit; and contacting a coated substrate
with the exhaust gas, the coated substrate comprising: a substrate;
a washcoat layer comprising oxidative catalytically active
micron-particles, the oxidative catalytically active
micron-particles comprising oxidative composite nanoparticles
embedded in a first micron-sized porous carrier, the oxidative
composite nanoparticles comprising a first support nanoparticle and
an oxidative catalytic nanoparticle; a washcoat layer comprising
reductive catalytically active micron-particles, the reductive
catalytically active micron-particles comprising reductive
composite nanoparticles embedded in a second micron-sized porous
carrier, the reductive composite nanoparticles comprising a second
support nanoparticle and a reductive catalytic nanoparticle; and a
washcoat layer comprising NO.sub.x trapping particles, and the
NO.sub.x trapping particles comprising a micron-sized cerium
oxide-containing material.
116. The method of claim 115, wherein the micron-sized cerium
oxide-containing material comprises cerium oxide, cerium-zirconium
oxide, cerium-lanthanum oxide, cerium-yttrium oxide,
cerium-zirconium-lanthanum oxide, cerium-zirconium-yttrium oxide,
cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide.
117. The method of claim 116, wherein the micron-sized cerium
oxide-containing material comprises cerium-zirconium-lanthanum
oxide or cerium-zirconium-lanthanum-yttrium oxide.
118. The method of claim 115, wherein the washcoat layer comprising
reductive catalytically active micron-particles is located closer
to the substrate than the washcoat layer comprising oxidative
catalytically active micron-particles.
119. The method of claim 118, wherein the washcoat layer comprising
oxidative catalytically active micron-particles is located closer
to the substrate than the washcoat layer comprising NO.sub.x
trapping particles.
120. The method claim of 115, wherein the NO.sub.x trapping
particles further comprise barium oxide impregnated in the
micron-sized cerium oxide-containing material.
121. The coated substrate of claim 120, wherein the barium oxide is
impregnated in the micron-sized cerium oxide or the micron-sized
cerium oxide-containing material by wet chemistry.
122. The method of claim 115, wherein the NO.sub.x trapping
particles further comprise platinum or palladium impregnated in the
micron-sized cerium oxide-containing material.
123. The method of claim 122, wherein the platinum or palladium is
plasma-generated.
124. The method of claim 122, wherein the platinum or palladium is
impregnated in the micron-sized cerium oxide-containing material by
wet chemistry.
125. The method of claim 115, wherein the NO.sub.x trapping
particles further comprise the perovskite FeBaO.sub.3 impregnated
in the micron-sized cerium oxide-containing material.
126. The method of claim 115, wherein the NO.sub.x trapping
particles further comprise metal oxides selected from the group
consisting of samarium, zinc, copper, iron, and silver oxides
impregnated in the micron-sized cerium oxide-containing
material.
127. The method of claim 115, wherein the washcoat layer comprising
NO.sub.x trapping particles further comprises micron-sized aluminum
oxide particles.
128. The method of claim 115, wherein the oxidative catalytically
active micron-particles comprise a material selected from the group
consisting of platinum, palladium, and a platinum-palladium
alloy.
129. The method of claim 115, wherein the NO.sub.x trapping
particles further comprise zirconium oxide.
130. The method of claim 115, wherein the first micron-sized
carrier particle or the first support nanoparticle comprises
aluminum oxide.
131. The method of claim 115, wherein the second micron-sized
carrier particle or the second support nanoparticle comprises
cerium oxide.
132. The method of claim 115, wherein the washcoat layer comprising
the oxidative catalytically active micron-particles or the washcoat
layer comprising reductive catalytically active micron-particles
further comprises filler particles or boehmite particles; wherein
the filler particles are metal oxide particles.
133. The method of claim 115, wherein the conduit is configured to
receive the exhaust gas from an engine configured to alternatively
operate in lean-burn or rich-burn.
134. The method of claim 115, wherein the coated substrate is
housed within a catalytic converter configured to receive the
exhaust gas.
135. A method of treating an exhaust gas, comprising contacting a
coated substrate with the exhaust gas, the coated substrate
comprising: a substrate; a washcoat layer comprising oxidative
catalytically active composite nanoparticles attached to a first
micron-sized support particle, the oxidative catalytically active
composite nanoparticles being plasma-generated and comprising a
first support nanoparticle and an oxidative catalytic nanoparticle;
a washcoat layer comprising reductive catalytically active
composite nanoparticles attached to a second micron-sized support
particle, the reductive catalytically active composite
nanoparticles being plasma-generated and comprising a second
support nanoparticle and a reductive catalytic nanoparticle; and a
washcoat layer comprising NO.sub.x trapping particles, and the
NO.sub.x trapping particles comprising a micron-sized cerium
oxide-containing material.
136. A method of treating an exhaust gas, comprising contacting a
coated substrate with the exhaust gas, the coated substrate
comprising: a substrate; a first washcoat layer comprising
oxidative catalytically active micron-particles, the oxidative
catalytically active micron-particles comprising oxidative
composite nanoparticles bonded to a first micron-sized carrier
particle, the oxidative composite nanoparticles comprising a first
support nanoparticle and an oxidative catalytic nanoparticle; and a
second washcoat layer comprising reductive catalytically active
micron-particles and NO.sub.x trapping particles, the reductive
catalytically active micron-particles comprising reductive
composite nanoparticles bonded to a second micron-sized carrier
particle, the reductive composite nanoparticles comprising a second
support nanoparticle and a reductive catalytic nanoparticle, and
the NO.sub.x trapping particles comprising a micron-sized cerium
oxide-containing material.
137. A method of treating an exhaust gas, comprising contacting a
coated substrate with the exhaust gas, the coated substrate
comprising: a substrate; a washcoat layer comprising oxidative
catalytically active micron-particles, the oxidative catalytically
active micron-particles comprising oxidative composite
nanoparticles embedded in a first micron-sized porous carrier, the
oxidative composite nanoparticles comprising a first support
nanoparticle and an oxidative catalytic nanoparticle; and a
washcoat layer comprising reductive catalytically active micron-
particles and NOx trapping particles, the reductive catalytically
active micron-particles comprising reductive composite
nanoparticles embedded in a second micron-sized porous carrier, the
reductive composite nanoparticles comprising a second support
nanoparticle and a reductive catalytic nanoparticle, and the NOx
trapping particles comprising a micron-sized cerium
oxide-containing material.
138. A method of treating an exhaust gas, comprising contacting a
coated substrate with the exhaust gas, the coated substrate
comprising: a substrate; a washcoat layer comprising oxidative
catalytically active composite nanoparticles attached to a first
micron-sized support particle, the oxidative catalytically active
composite nanoparticles being plasma-generated and comprising a
first support nanoparticle and an oxidative catalytic nanoparticle;
and a washcoat layer comprising NOx trapping particles and
reductive catalytically active composite nanoparticles attached to
a second micron-sized support particle, the reductive catalytically
active composite nanoparticles being plasma-generated and
comprising a second support nanoparticle and a reductive catalytic
nanoparticle, and the NOx trapping particles comprising a
micron-sized cerium oxide-containing material.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority benefit of U.S. Provisional
Patent Application No. 61/894,346, filed Oct. 22, 2013. The entire
contents of that application are hereby incorporated by reference
herein.
FIELD OF THE INVENTION
[0002] The present disclosure relates to the field of catalysts.
More specifically, the present invention relates to nanoparticle
catalysts and storage materials for nitrogen oxides as part of a
lean NO.sub.x trap (LNT) system.
BACKGROUND OF THE INVENTION
[0003] Car exhaust primarily contains harmful gases such as carbon
monoxide (CO), nitrogen oxides (NO.sub.x), and hydrocarbons.
Environmental concerns and government regulations have led efforts
to remove these noxious combustion products from vehicle exhaust by
conversion to more benign gases such as carbon dioxide (CO.sub.2),
nitrogen (N.sub.2), and water (H.sub.2O). In order to accomplish
this conversion, the exhaust gases must pass through a treatment
system that contains materials that can oxidize CO to CO.sub.2,
reduce NO.sub.x to N.sub.2 and H.sub.2O, and oxidize hydrocarbons
to CO.sub.2 and H.sub.2O. Recently, lean-burn gasoline and diesel
engines have increased in popularity due to their improved fuel
economy. These engines, however, have high amounts of oxygen
present in the exhaust gas, which leads to inhibition of the
catalytic reduction of NO.sub.x.
[0004] One solution to this problem has been the use of lean
NO.sub.x traps (LNTs). LNTs absorb, store, or trap nitrogen oxides
during lean-burn engine operation (i.e., when excess oxygen is
present), and release and convert these gases when the oxygen
content in the exhaust gas is reduced. LNTs are typically composed
of one or more platinum group metals (PGMs) such as platinum,
palladium, or rhodium, and an alkali earth metal such as barium.
Although these traps are effective at removing NO.sub.x from the
exhaust of lean-burn vehicles, high loadings of expensive PGMs are
required. As such, there is a significant cost associated with the
use of these LNTs.
[0005] Accordingly, there is a need for non-platinum group metal
materials that effectively reduce and/or store NO.sub.x for use as
less expensive alternatives in LNTs.
SUMMARY OF THE INVENTION
[0006] Described herein are coated substrates for use as NOx traps,
washcoat formulations for preparing coated substrates for use as
NOx traps, methods for preparing coated substrates for use as NOx
traps, and systems incorporating coated substrates employed as NOx
traps in an emission-control system. The NOx traps are, in one
embodiment, lean NOx traps, which can trap NOx species from engine
emissions during lean-cycle engine operation, and which can be
purged of NOx species during rich-cycle engine operation.
[0007] The present invention provides, in a general embodiment, a
coated substrate comprising:
[0008] a substrate;
[0009] a washcoat layer comprising oxidative catalytically active
composite nanoparticles attached/bonded to or embedded in a first
micron-sized support particle, the oxidative catalytically active
composite nanoparticles comprising a first support nanoparticle and
an oxidative catalytic nanoparticle;
[0010] a washcoat layer comprising reductive catalytically active
composite nanoparticles attached/bonded to or embedded in a second
micron-sized support particle, the reductive catalytically active
composite nanoparticles comprising a second support nanoparticle
and a reductive catalytic nanoparticle;
[0011] wherein either: [0012] (i) the washcoat layer comprising
reductive catalytically active composite nanoparticles further
comprises NOx trapping particles, the NOx trapping particles
comprising micron-sized cerium oxide; or [0013] (ii) the coated
substrate comprises a further washcoat layer comprising NOx
trapping particles, the NOx trapping particles comprising
micron-sized cerium oxide. Such a coated substrate may have any of
the preferred and optional features described below.
[0014] The present invention also provides, in a general
embodiment, a method of making a coated substrate comprising, in
any order:
[0015] coating the substrate with a washcoat layer comprising
oxidative catalytically active composite nanoparticles
attached/bonded to or embedded in a first micron-sized support
particle, the oxidative catalytically active composite
nanoparticles comprising a first support nanoparticle and an
oxidative catalytic nanoparticle;
[0016] coating the substrate with a washcoat layer comprising
reductive catalytically active composite nanoparticles
attached/bonded to or embedded in a second micron-sized support
particle, the reductive catalytically active composite
nanoparticles comprising a second support nanoparticle and a
reductive catalytic nanoparticle;
[0017] wherein either: [0018] (i) the washcoat layer comprising
reductive catalytically active composite nanoparticles further
comprises NOx trapping particles, the NOx trapping particles
comprising micron-sized cerium oxide; or [0019] (ii) the method
additionally comprises, in any order with respect to coating the
substrate with other washcoat layers, coating the substrate with a
washcoat layer comprising NOx trapping particles, the NOx trapping
particles comprising micron-sized cerium oxide. Such a method of
making a coated substrate, as well as the coated substrate so
prepared, may have any of the preferred and optional features
described below.
[0020] Described herein is a coated substrate comprising a
substrate; a washcoat layer comprising oxidative catalytically
active Nano-on-Nano-on-micro (NNm) particles, the oxidative
catalytically active Nano-on-Nano-on-micro (NNm) particles
comprising composite nanoparticles bonded to a first micron-sized
carrier particle, and the composite nanoparticles comprising a
first support nanoparticle and an oxidative catalytic nanoparticle;
and a washcoat layer comprising reductive catalytically active
Nano-on-Nano-on-micro (NNm) particles and NO.sub.x trapping
particles, the reductive catalytically active Nano-on-Nano-on-micro
(NNm) particles comprising composite nanoparticles bonded to a
second micron-sized carrier particle, the composite nanoparticles
comprising a second support nanoparticle and a reductive catalytic
nanoparticle, and the NO.sub.x trapping particles comprising
micron-sized cerium oxide or micron-sized cerium oxide-containing
material. In further embodiments, the NO.sub.x trapping particles
further comprise barium oxide impregnated in the micron-sized
cerium oxide or micron-sized cerium oxide-containing material,
and/or further comprise platinum, palladium, or both platinum and
palladium impregnated in the micron-sized cerium oxide or
micron-sized cerium oxide-containing material. In any of the
disclosed embodiments of the NOx trapping particles, the
micron-sized cerium oxide-containing material can comprise cerium
oxide, cerium-zirconium oxide, cerium-lanthanum oxide,
cerium-yttrium oxide, cerium-zirconium-lanthanum oxide,
cerium-zirconium-yttrium oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0.13La.sub.0.04O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide.
[0021] The barium oxide of any of the embodiments disclosed herein
can be plasma-generated and subsequently impregnated in the
micron-sized cerium oxide or micron-sized cerium oxide-containing
material; in alternative embodiments, the barium oxide can be
impregnated in the micron-sized cerium oxide or micron-sized cerium
oxide-containing material by the use of wet chemistry employing
barium oxide precurors (such as barium acetate). The platinum
and/or palladium of any of the preceding embodiments can be
plasma-generated and subsequently impregnated in the micron-sized
cerium oxide or micron-sized cerium oxide-containing material; in
alternative embodiments, the platinum and/or palladium can be
impregnated in the micron-sized cerium oxide or micron-sized cerium
oxide-containing material by the use of wet chemistry employing
platinum precursors and/or palladium precurors. In any of the
disclosed embodiments, including the foregoing embodiments, the
NO.sub.x trapping particles can further comprise the perovskite
FeBaO.sub.3 impregnated in the micron-sized cerium oxide or
micron-sized cerium oxide-containing material. In any of the
disclosed embodiments, the micron-sized cerium oxide-containing
material can comprise cerium oxide, cerium-zirconium oxide,
cerium-lanthanum oxide, cerium-yttrium oxide,
cerium-zirconium-lanthanum oxide, cerium-zirconium-yttrium oxide,
cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.-.13La.sub.0.04O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 40% cerium oxide, 50%
zirconium oxide, 5% lanthanum oxide, and 5% yttrium oxide.
[0022] In any of the disclosed embodiments, including the foregoing
embodiments, the NO.sub.x trapping particles can further comprise
metal oxides selected from the group consisting of samarium, zinc,
copper, iron, and silver impregnated in the micron-sized cerium
oxide or micron-sized cerium oxide-containing material. In any of
the disclosed embodiments, the micron-sized cerium oxide-containing
material can comprise cerium oxide, cerium-zirconium oxide,
cerium-lanthanum oxide, cerium-yttrium oxide,
cerium-zirconium-lanthanum oxide, cerium-zirconium-yttrium oxide,
cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0.13La.sub.0.04O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide.
[0023] In any of the disclosed embodiments, including the foregoing
embodiments, the NO.sub.x trapping particles can be prepared by wet
chemistry.
[0024] In any of the disclosed embodiments, including the foregoing
embodiments, the NO.sub.x trapping particles can further comprise
micron-sized aluminum oxide particles.
[0025] In any of the disclosed embodiments, including the foregoing
embodiments, the micron-sized aluminum oxide particles are
Nano-on-Nano-on-micro (NNm) particles. In any of the disclosed
embodiments, including the foregoing embodiments, the
Nano-on-Nano-on-micro (NNm) particles can comprise platinum and/or
palladium; and/or can comprise a non-platinum group metal. The
non-platinum group metal can be selected from the group consisting
of tungsten, molybdenum, niobium, manganese, chromium, and mixtures
thereof.
[0026] In any of the disclosed embodiments, including the foregoing
embodiments, the oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles can comprise at least one
platinum group metal. The platinum group metal can be platinum,
palladium, or both platinum and palladium. In any of the disclosed
embodiments, including the foregoing embodiments, the platinum and
palladium is an alloy of platinum and palladium. In any of the
disclosed embodiments, including the foregoing embodiments, the
platinum and palladium are added as individual metals.
[0027] In any of the disclosed embodiments, including the foregoing
embodiments, the reductive catalytically active
Nano-on-Nano-on-micro (NNm) particles can comprise a platinum group
metal. The platinum group metal can be rhodium.
[0028] In any of the disclosed embodiments, including the foregoing
embodiments, the NO.sub.x trapping particles comprising
micron-sized cerium oxide or micron-sized cerium oxide-containing
material can further comprise zirconium oxide. In any of the
disclosed embodiments, the micron-sized cerium oxide-containing
material can comprise cerium oxide, cerium-zirconium oxide,
cerium-lanthanum oxide, cerium-yttrium oxide,
cerium-zirconium-lanthanum oxide, cerium-zirconium-yttrium oxide,
cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0.13La.sub.0.04O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.006O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide.
[0029] In any of the disclosed embodiments, including the foregoing
embodiments, the first support nanoparticle and/or the first
micron-sized carrier particle can comprise aluminum oxide. In any
of the disclosed embodiments, including the foregoing embodiments,
the second support nanoparticle and/or the second micron-sized
carrier particle can comprise cerium oxide. In any of the disclosed
embodiments, including the foregoing embodiments, the first and
second support nanoparticles can have an average diameter of about
10 nm to about 20 nm, for example, about 1 nm to about 5 nm. In any
of the disclosed embodiments, the micron-sized cerium
oxide-containing material can comprise cerium oxide,
cerium-zirconium oxide, cerium-lanthanum oxide, cerium-yttrium
oxide, cerium-zirconium-lanthanum oxide, cerium-zirconium-yttrium
oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.1.13La.sub.0.04O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide.
[0030] In any of the disclosed embodiments, including the foregoing
embodiments, of the coated substrate, the washcoat layer can
comprise oxidative catalytically active Nano-on-Nano-on-micro (NNm)
particles, metal oxide particles, and boehmite particles.
[0031] In any of the disclosed embodiments, including the foregoing
embodiments, the metal oxide particles can be aluminum oxide
particles.
[0032] In any of the disclosed embodiments, including the foregoing
embodiments, the oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles can comprise 35% to 75% by
weight of the combination of the oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles, boehmite particles, and
aluminum oxide particles; and/or the aluminum oxide particles can
comprise 30% to 70% by weight of the combination of the oxidative
catalytically active Nano-on-Nano-on-micro (NNm) particles,
boehmite particles, and aluminum oxide particles; and/or the
boehmite particles can comprise 2% to 5% by weight of the
combination of the oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles, boehmite particles, and
aluminum oxide particles.
[0033] In any of the disclosed embodiments, including the foregoing
embodiments, the washcoat layer can comprise 50% by weight of the
oxidative catalytically active Nano-on-Nano-on-micro (NNm)
particles, 3% by weight of the boehmite particles, and 47% by
weight of the aluminum oxide particles.
[0034] In any of the disclosed embodiments, including the foregoing
embodiments, the washcoat layer comprising reductive catalytically
active Nano-on-Nano-on-micro (NNm) particles and NO.sub.x trapping
particles can further comprise boehmite. In any of the disclosed
embodiments, including the foregoing embodiments, the reductive
catalytically active Nano-on-Nano-on-micro (NNm) particles comprise
3% to 40% by weight of the combination of the reductive
catalytically active Nano-on-Nano-on-micro (NNm) particles,
NO.sub.x trapping particles, and boehmite particles, the NO.sub.x
trapping particles can comprise 30% to 98% by weight of the
combination of the reductive catalytically active
Nano-on-Nano-on-micro (NNm) particles, NO.sub.x trapping particles,
and boehmite particles, and the boehmite particles can comprise 1%
to 5% by weight of the combination of the reductive catalytically
active Nano-on-Nano-on-micro (NNm) particles, NO.sub.x trapping
particles, and boehmite particles.
[0035] In any of the disclosed embodiments, including the foregoing
embodiments, the washcoat layer can comprise reductive
catalytically active Nano-on-Nano-on-micro (NNm) particles and
NO.sub.x trapping particles comprises 15% by weight of the
reductive catalytically active Nano-on-Nano-on-micro (NNm)
particles, 83% by weight of the NO.sub.x trapping particles, and 2%
by weight of the boehmite particles.
[0036] In any of the disclosed embodiments, including the foregoing
embodiments, the substrate can comprise cordierite. In any of the
disclosed embodiments, including the foregoing embodiments, the
substrate can comprise a honeycomb structure.
[0037] In any of the disclosed embodiments, including the foregoing
embodiments, the washcoat layer on the coated substrate comprising
oxidative catalytically active Nano-on-Nano-on-micro (NNm)
particles has a thickness of 25 g/L to 150 g/L.
[0038] In any of the disclosed embodiments, including the foregoing
embodiments, the washcoat layer on the coated substrate comprising
reductive catalytically active Nano-on-Nano-on-micro (NNm)
particles and NO.sub.x trapping particles has a thickness of 100
g/L to 400 g/L.
[0039] In any of the disclosed embodiments, including the foregoing
embodiments, the coated substrate has a platinum group metal
loading of 4 g/L or less and a light-off temperature for carbon
monoxide at least 5.degree. C. lower than the light-off temperature
of a substrate with the same platinum group metal loading deposited
by wet-chemistry methods.
[0040] In any of the disclosed embodiments, including the foregoing
embodiments, the coated substrate has a platinum group metal
loading of about 3.0 g/L to about 5.5 g/L, wherein after 125,000
miles of operation in a vehicular catalytic converter, the coated
substrate has a light-off temperature for carbon monoxide at least
5.degree. C. lower than a coated substrate prepared by depositing
platinum group metals by wet chemical methods having the same
platinum group metal loading after 125,000 miles of operation in a
vehicular catalytic converter.
[0041] In any of the disclosed embodiments, including the foregoing
embodiments, the coated substrate has a platinum group metal
loading of about 3.0 g/L to about 5.5 g/L, wherein after aging for
16 hours at 800.degree. C., the coated substrate has a light-off
temperature for carbon monoxide at least 5.degree. C. lower than a
coated substrate prepared by depositing platinum group metals by
wet chemical methods having the same platinum group metal loading
after aging for 16 hours at 800.degree. C.
[0042] Further described herein is a catalytic converter comprising
a coated substrate of any one of the disclosed embodiments,
including the foregoing embodiments. Further described herein is an
exhaust treatment system comprising a conduit for exhaust gas and
the foregoing catalytic converter. Further described herein is a
vehicle comprising the foregoing catalytic converter.
[0043] Further described herein is a method of treating an exhaust
gas, comprising contacting the coated substrate of any of the
foregoing embodiments with the exhaust gas. In further embodiments,
the substrate can be housed within a catalytic converter configured
to receive the exhaust gas.
[0044] Further described herein is a coated substrate comprising a
substrate; a washcoat layer comprising oxidative catalytically
active Nano-on-Nano-in-Micro (NNiM) particles, the oxidative
catalytically active Nano-on-Nano-in-Micro (NNiM) particles
comprising composite nanoparticles embedded in a first micron-sized
porous carrier, and the composite nanoparticles comprising a first
support nanoparticle and an oxidative catalytic nanoparticle; and a
washcoat layer comprising reductive catalytically active
Nano-on-Nano-in-Micro (NNiM) particles and NO.sub.x trapping
particles, the reductive catalytically active Nano-on-Nano-in-Micro
(NNiM) particles comprising composite nanoparticles embedded in a
second micron-sized porous carrier, the composite nanoparticles
comprising a second support nanoparticle and a reductive catalytic
nanoparticle, and the NO.sub.x trapping particles comprising
micron-sized cerium oxide or micron-sized cerium oxide-containing
material. The variations described above for the previously
described coated substrate using NNm material are also applicable
to this substrate using NNiM material where compatible. In all
embodiments disclosed herein, oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles can comprise nano-on-nano
composite nanoparticles comprise a platinum catalytic nanoparticle
disposed on an aluminum oxide support particle; where the
nano-on-nano composite nanoparticles comprise a palladium catalytic
nanoparticle disposed on an aluminum oxide support particle; or
where the nano-on-nano composite nanoparticles comprise a
platinum/palladium alloy catalytic nanoparticle disposed on an
aluminum oxide support particle; and one or more of those NN
particles is then embedded in a porous carrier formed of aluminum
oxide which is formed around the NN particles, which carrier is
then ground or milled into micron-sized particles. In all
embodiments disclosed herein, reductive catalytically active
Nano-on-Nano-in-Micro (NNiM) particles can comprise nano-on-nano
composite nanoparticles comprising a rhodium catalytic nanoparticle
disposed on a cerium oxide support particle; where the nano-on-nano
composite nanoparticles comprise a rhodium catalytic nanoparticle
disposed on a cerium-zirconium oxide support particle; where the
nano-on-nano composite nanoparticles comprise a rhodium catalytic
nanoparticle disposed on a cerium-zirconium-lanthanum oxide support
particle; or where the nano-on-nano composite nanoparticles
comprise a rhodium catalytic nanoparticle disposed on a
cerium-zirconium-lanthanum-yttrium oxide support particle; and one
or more of those NN particles is then embedded in a porous carrier
formed of porous cerium oxide, cerium-zirconium oxide,
cerium-zirconium-lanthanum oxide, or
cerium-zirconium-lanthanum-yttrium oxide carrier, where the porous
carrier is formed around the NN particles, which carrier is then
ground or milled into micron-sized particles. Aluminum oxide porous
material can also be used as the porous material in which any of
the foregoing rhodium-containing composite NN nanoparticles can be
embedded. In any of the disclosed embodiments, the micron-sized
cerium oxide-containing material can comprise cerium oxide,
cerium-zirconium oxide, cerium-lanthanum oxide, cerium-yttrium
oxide, cerium-zirconium-lanthanum oxide, cerium-zirconium-yttrium
oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0.13La.sub.0.04O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide.
[0045] Further described is a coated substrate comprising a
substrate; a washcoat layer comprising oxidative catalytically
active composite nanoparticles attached to a first micron-sized
support particle, the oxidative catalytically active composite
nanoparticles being plasma-generated and comprising a first support
nanoparticle and an oxidative catalytic nanoparticle; and a
washcoat layer comprising NO.sub.x trapping particles and reductive
catalytically active composite nanoparticles attached to a second
micron-sized support particle, the reductive catalytically active
composite nanoparticles being plasma-generated and comprising a
second support nanoparticle and a reductive catalytic nanoparticle,
and the NO.sub.x trapping particles comprising micron-sized cerium
oxide or micron-sized cerium oxide-containing material. The
variations described above for the previously described coated
substrate are also applicable to this substrate. In any of the
disclosed embodiments, the micron-sized cerium oxide-containing
material can comprise cerium oxide, cerium-zirconium oxide,
cerium-lanthanum oxide, cerium-yttrium oxide,
cerium-zirconium-lanthanum oxide, cerium-zirconium-yttrium oxide,
cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0.13La.sub.0.04O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide.
[0046] Also described herein is a coated substrate comprising a
substrate; a first washcoat layer comprising oxidative
catalytically active Nano-on-Nano-on-micro (NNm) particles, the
oxidative catalytically active Nano-on-Nano-on-micro (NNm)
particles comprising composite nanoparticles bonded to a first
micron-sized carrier particle, and the composite nanoparticles
comprising a first support nanoparticle and an oxidative catalytic
nanoparticle; a second washcoat layer comprising reductive
catalytically active Nano-on-Nano-on-micro (NNm) particles, the
reductive catalytically active Nano-on-Nano-on-micro (NNm)
particles comprising composite nanoparticles bonded to a second
micron-sized carrier particle, the composite nanoparticles
comprising a second support nanoparticle and a reductive catalytic
nanoparticle, and a third washcoat layer comprising NO.sub.x
trapping particles, the NO.sub.x trapping particles comprising
micron-sized cerium oxide or micron-sized cerium oxide-containing
material. The washcoat layers can be disposed in any order with
respect to the substrate (that is, S-1-2-3, S-1-3-2, S-2-1-3,
S-2-3-1, S-3-1-2, S-3-2-1, where S is the substrate and 1, 2, and 3
represent the first, second, and third washcoat layers,
respectively). In further embodiments, the NO.sub.x trapping
particles further comprise barium oxide impregnated in the
micron-sized cerium oxide or micron-sized cerium oxide-containing
material, and/or further comprise platinum, palladium, or both
platinum and palladium impregnated in the micron-sized cerium oxide
or micron-sized cerium oxide-containing material. In any of the
disclosed embodiments of the NOx trapping particles, the
micron-sized cerium oxide-containing material can comprise cerium
oxide, cerium-zirconium oxide, cerium-lanthanum oxide,
cerium-yttrium oxide, cerium-zirconium-lanthanum oxide,
cerium-zirconium-yttrium oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0.13La.sub.0.04O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide.
[0047] The barium oxide of any of the embodiments disclosed herein
can be plasma-generated and subsequently impregnated in the
micron-sized cerium oxide or micron-sized cerium oxide-containing
material; in alternative embodiments, the barium oxide can be
impregnated in the micron-sized cerium oxide or micron-sized cerium
oxide-containing material by the use of wet chemistry employing
barium oxide precurors (such as barium acetate). The platinum
and/or palladium of any of the preceding embodiments can be
plasma-generated and subsequently impregnated in the micron-sized
cerium oxide or micron-sized cerium oxide-containing material; in
alternative embodiments, the platinum and/or palladium can be
impregnated in the micron-sized cerium oxide or micron-sized cerium
oxide-containing material by the use of wet chemistry employing
platinum precursors and/or palladium precurors. In any of the
disclosed embodiments, including the foregoing embodiments, the
NO.sub.x trapping particles can further comprise the perovskite
FeBaO.sub.3 impregnated in the micron-sized cerium oxide or
micron-sized cerium oxide-containing material. In any of the
disclosed embodiments, the micron-sized cerium oxide-containing
material can comprise cerium oxide, cerium-zirconium oxide,
cerium-lanthanum oxide, cerium-yttrium oxide,
cerium-zirconium-lanthanum oxide, cerium-zirconium-yttrium oxide,
cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0.13La.sub.0.04O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide.
[0048] In any of the disclosed embodiments, including the foregoing
embodiments, the NO.sub.x trapping particles can further comprise
metal oxides selected from the group consisting of samarium, zinc,
copper, iron, and silver impregnated in the micron-sized cerium
oxide or micron-sized cerium oxide-containing material. In any of
the disclosed embodiments, the micron-sized cerium oxide-containing
material can comprise cerium oxide, cerium-zirconium oxide,
cerium-lanthanum oxide, cerium-yttrium oxide,
cerium-zirconium-lanthanum oxide, cerium-zirconium-yttrium oxide,
cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0.13La.sub.0.04O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide.
[0049] In any of the disclosed embodiments, including the foregoing
embodiments, the NO.sub.x trapping particles can be prepared by wet
chemistry.
[0050] In any of the disclosed embodiments, including the foregoing
embodiments, the NO.sub.x trapping particles can further comprise
micron-sized aluminum oxide particles.
[0051] In any of the disclosed embodiments, including the foregoing
embodiments, the micron-sized aluminum oxide particles are
Nano-on-Nano-on-micro (NNm) particles. In any of the disclosed
embodiments, including the foregoing embodiments, the
Nano-on-Nano-on-micro (NNm) particles can comprise platinum and/or
palladium; and/or can comprise a non-platinum group metal. The
non-platinum group metal can be selected from the group consisting
of tungsten, molybdenum, niobium, manganese, chromium, and mixtures
thereof.
[0052] In any of the disclosed embodiments, including the foregoing
embodiments, the oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles can comprise at least one
platinum group metal. The platinum group metal can be platinum,
palladium, or both platinum and palladium. In any of the disclosed
embodiments, including the foregoing embodiments, the platinum and
palladium is an alloy of platinum and palladium. In any of the
disclosed embodiments, including the foregoing embodiments, the
platinum and palladium are added as individual metals.
[0053] In any of the disclosed embodiments, including the foregoing
embodiments, the reductive catalytically active
Nano-on-Nano-on-micro (NNm) particles can comprise a platinum group
metal. The platinum group metal can be rhodium.
[0054] In any of the disclosed embodiments, including the foregoing
embodiments, the NO.sub.x trapping particles comprising
micron-sized cerium oxide or micron-sized cerium oxide-containing
material can further comprise zirconium oxide. In any of the
disclosed embodiments, the micron-sized cerium oxide-containing
material can comprise cerium oxide, cerium-zirconium oxide,
cerium-lanthanum oxide, cerium-yttrium oxide,
cerium-zirconium-lanthanum oxide, cerium-zirconium-yttrium oxide,
cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0.13La.sub.0.04O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide.
[0055] In any of the disclosed embodiments, including the foregoing
embodiments, the first support nanoparticle and/or the first
micron-sized carrier particle can comprise aluminum oxide. In any
of the disclosed embodiments, including the foregoing embodiments,
the second support nanoparticle and/or the second micron-sized
carrier particle can comprise cerium oxide. In any of the disclosed
embodiments, including the foregoing embodiments, the first and
second support nanoparticles can have an average diameter of about
10 nm to about 20 nm, for example, about 1 nm to about 5 nm. In any
of the disclosed embodiments, the micron-sized cerium
oxide-containing material can comprise cerium oxide,
cerium-zirconium oxide, cerium-lanthanum oxide, cerium-yttrium
oxide, cerium-zirconium-lanthanum oxide, cerium-zirconium-yttrium
oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0.13La.sub.0.04O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide.
[0056] In any of the disclosed embodiments, including the foregoing
embodiments, of the coated substrate, the washcoat layer can
comprise oxidative catalytically active Nano-on-Nano-on-micro (NNm)
particles, metal oxide particles, and boehmite particles.
[0057] In any of the disclosed embodiments, including the foregoing
embodiments, the metal oxide particles can be aluminum oxide
particles.
[0058] In any of the disclosed embodiments, including the foregoing
embodiments, the oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles can comprise 35% to 75% by
weight of the combination of the oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles, boehmite particles, and
aluminum oxide particles; and/or the aluminum oxide particles can
comprise 30% to 70% by weight of the combination of the oxidative
catalytically active Nano-on-Nano-on-micro (NNm) particles,
boehmite particles, and aluminum oxide particles; and/or the
boehmite particles can comprise 2% to 5% by weight of the
combination of the oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles, boehmite particles, and
aluminum oxide particles.
[0059] In any of the disclosed embodiments, including the foregoing
embodiments, the washcoat layer can comprise 50% by weight of the
oxidative catalytically active Nano-on-Nano-on-micro (NNm)
particles, 3% by weight of the boehmite particles, and 47% by
weight of the aluminum oxide particles.
[0060] In any of the disclosed embodiments, including the foregoing
embodiments, the washcoat layer comprising reductive catalytically
active Nano-on-Nano-on-micro (NNm) particles and NO.sub.x trapping
particles can further comprise boehmite. In any of the disclosed
embodiments, including the foregoing embodiments, the reductive
catalytically active Nano-on-Nano-on-micro (NNm) particles comprise
3% to 40% by weight of the combination of the reductive
catalytically active Nano-on-Nano-on-micro (NNm) particles,
NO.sub.x trapping particles, and boehmite particles, the NO.sub.x
trapping particles can comprise 30% to 98% by weight of the
combination of the reductive catalytically active
Nano-on-Nano-on-micro (NNm) particles, NO.sub.x trapping particles,
and boehmite particles, and the boehmite particles can comprise 1%
to 5% by weight of the combination of the reductive catalytically
active Nano-on-Nano-on-micro (NNm) particles, NO.sub.x trapping
particles, and boehmite particles.
[0061] In any of the disclosed embodiments, including the foregoing
embodiments, the washcoat layer can comprise reductive
catalytically active Nano-on-Nano-on-micro (NNm) particles and
NO.sub.x trapping particles comprises 15% by weight of the
reductive catalytically active Nano-on-Nano-on-micro (NNm)
particles, 83% by weight of the NO.sub.x trapping particles, and 2%
by weight of the boehmite particles.
[0062] In any of the disclosed embodiments, including the foregoing
embodiments, the substrate can comprise cordierite. In any of the
disclosed embodiments, including the foregoing embodiments, the
substrate can comprise a honeycomb structure.
[0063] In any of the disclosed embodiments, including the foregoing
embodiments, the washcoat layer on the coated substrate comprising
oxidative catalytically active Nano-on-Nano-on-micro (NNm)
particles has a thickness of 25 g/L to 150 g/L.
[0064] In any of the disclosed embodiments, including the foregoing
embodiments, the washcoat layer on the coated substrate comprising
reductive catalytically active Nano-on-Nano-on-micro (NNm)
particles has a thickness of 25 g/L to 150 g/L.
[0065] In any of the disclosed embodiments, including the foregoing
embodiments, the washcoat layer on the coated substrate comprising
NO.sub.x trapping particles has a thickness of 100 g/L to 400
g/L.
[0066] In any of the disclosed embodiments, including the foregoing
embodiments, the coated substrate has a platinum group metal
loading of 4 g/L or less and a light-off temperature for carbon
monoxide at least 5.degree. C. lower than the light-off temperature
of a substrate with the same platinum group metal loading deposited
by wet-chemistry methods.
[0067] In any of the disclosed embodiments, including the foregoing
embodiments, the coated substrate has a platinum group metal
loading of about 3.0 g/L to about 5.5 g/L, wherein after 125,000
miles of operation in a vehicular catalytic converter, the coated
substrate has a light-off temperature for carbon monoxide at least
5.degree. C. lower than a coated substrate prepared by depositing
platinum group metals by wet chemical methods having the same
platinum group metal loading after 125,000 miles of operation in a
vehicular catalytic converter.
[0068] In any of the disclosed embodiments, including the foregoing
embodiments, the coated substrate has a platinum group metal
loading of about 3.0 g/L to about 5.5 g/L, wherein after aging for
16 hours at 800.degree. C., the coated substrate has a light-off
temperature for carbon monoxide at least 5.degree. C. lower than a
coated substrate prepared by depositing platinum group metals by
wet chemical methods having the same platinum group metal loading
after aging for 16 hours at 800.degree. C.
[0069] Further described herein is a catalytic converter comprising
a coated substrate of any one of the disclosed embodiments,
including the foregoing embodiments. Further described herein is an
exhaust treatment system comprising a conduit for exhaust gas and
the foregoing catalytic converter. Further described herein is a
vehicle comprising the foregoing catalytic converter.
[0070] Further described herein is a method of treating an exhaust
gas, comprising contacting the coated substrate of any of the
foregoing embodiments with the exhaust gas. In further embodiments,
the substrate can be housed within a catalytic converter configured
to receive the exhaust gas.
[0071] Further described herein is a coated substrate comprising a
substrate; a first washcoat layer comprising oxidative
catalytically active Nano-on-Nano-in-Micro (NNiM) particles, the
oxidative catalytically active Nano-on-Nano-in-Micro (NNiM)
particles comprising composite nanoparticles embedded in a first
micron-sized porous carrier, and the composite nanoparticles
comprising a first support nanoparticle and an oxidative catalytic
nanoparticle; a second washcoat layer comprising reductive
catalytically active Nano-on-Nano-in-Micro (NNiM) particles, the
reductive catalytically active Nano-on-Nano-in-Micro (NNiM)
particles comprising composite nanoparticles embedded in a second
micron-sized porous carrier, the composite nanoparticles comprising
a second support nanoparticle and a reductive catalytic
nanoparticle; and a third washcoat layer comprising NO.sub.x
trapping particles, and the NO.sub.x trapping particles comprising
micron-sized cerium oxide or micron-sized cerium oxide-containing
material. The washcoat layers can be disposed in any order with
respect to the substrate (that is, S-1-2-3, S-1-3-2, S-2-1-3,
S-2-3-1, S-3-1-2, S-3-2-1, where S is the substrate and 1, 2, and 3
represent the first, second, and third washcoat layers,
respectively). The variations described above for the previously
described coated substrate using NNm material are also applicable
to this substrate using NNiM material where compatible. In all
embodiments disclosed herein, oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles can comprise nano-on-nano
composite nanoparticles comprise a platinum catalytic nanoparticle
disposed on an aluminum oxide support particle; where the
nano-on-nano composite nanoparticles comprise a palladium catalytic
nanoparticle disposed on an aluminum oxide support particle; or
where the nano-on-nano composite nanoparticles comprise a
platinum/palladium alloy catalytic nanoparticle disposed on an
aluminum oxide support particle; and one or more of those NN
particles is then embedded in a porous carrier formed of aluminum
oxide which is formed around the NN particles, which carrier is
then ground or milled into micron-sized particles. In all
embodiments disclosed herein, reductive catalytically active
Nano-on-Nano-in-Micro (NNiM) particles can comprise nano-on-nano
composite nanoparticles comprising a rhodium catalytic nanoparticle
disposed on a cerium oxide support particle; where the nano-on-nano
composite nanoparticles comprise a rhodium catalytic nanoparticle
disposed on a cerium-zirconium oxide support particle; where the
nano-on-nano composite nanoparticles comprise a rhodium catalytic
nanoparticle disposed on a cerium-zirconium-lanthanum oxide support
particle; or where the nano-on-nano composite nanoparticles
comprise a rhodium catalytic nanoparticle disposed on a
cerium-zirconium-lanthanum-yttrium oxide support particle; and one
or more of those NN particles is then embedded in a porous carrier
formed of porous cerium oxide, cerium-zirconium oxide,
cerium-zirconium-lanthanum oxide, or
cerium-zirconium-lanthanum-yttrium oxide carrier, where the porous
carrier is formed around the NN particles, which carrier is then
ground or milled into micron-sized particles. Aluminum oxide porous
material can also be used as the porous material in which any of
the foregoing rhodium-containing composite NN nanoparticles can be
embedded. In any of the disclosed embodiments, the micron-sized
cerium oxide-containing material can comprise cerium oxide,
cerium-zirconium oxide, cerium-lanthanum oxide, cerium-yttrium
oxide, cerium-zirconium-lanthanum oxide, cerium-zirconium-yttrium
oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0.13La.sub.0.04O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide.
[0072] Further described is a coated substrate comprising a
substrate; a washcoat layer comprising oxidative catalytically
active composite nanoparticles attached to a first micron-sized
support particle, the oxidative catalytically active composite
nanoparticles being plasma-generated and comprising a first support
nanoparticle and an oxidative catalytic nanoparticle; and a
washcoat layer comprising NO.sub.x trapping particles and reductive
catalytically active composite nanoparticles attached to a second
micron-sized support particle, the reductive catalytically active
composite nanoparticles being plasma-generated and comprising a
second support nanoparticle and a reductive catalytic nanoparticle,
and the reductive catalytically active composite nanoparticles
attached to or embedded in the NO.sub.x trapping particles, the
NO.sub.x trapping particles comprising micron-sized cerium oxide or
micron-sized cerium oxide-containing material. In further
embodiments, the NO.sub.x trapping particles comprise barium oxide
in an amount between 5% and 12%, such as 8%, by weight; the barium
oxide can be plasma-generated or deposited on the NO.sub.x trapping
particle by wet-chemistry methods. The variations described above
for the previously described coated substrate are also applicable
to this substrate. In any of the disclosed embodiments, the
micron-sized cerium oxide-containing material can comprise cerium
oxide, cerium-zirconium oxide, cerium-lanthanum oxide,
cerium-yttrium oxide, cerium-zirconium-lanthanum oxide,
cerium-zirconium-yttrium oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0.13La.sub.0.04O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide.
[0073] Further described is a method of forming a coated substrate,
the method comprising a) coating a substrate with a washcoat
composition comprising oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles, the oxidative catalytically
active Nano-on-Nano-on-micro (NNm) particles comprising composite
nanoparticles bonded to a first micron-sized carrier particle, and
the composite nanoparticles comprising a first support nanoparticle
and an oxidative catalytic nanoparticle; and b) coating the
substrate with a washcoat composition comprising reductive
catalytically active Nano-on-Nano-on-micro (NNm) particles and
NO.sub.x trapping particles, the reductive catalytically active
Nano-on-Nano-on-micro (NNm) particles comprising composite
nanoparticles bonded to second micron-sized carrier particle, and
the composite nanoparticles comprising a second support
nanoparticle and a reductive catalytic nanoparticle, and the
NO.sub.x trapping particles comprising micron-sized cerium oxide or
micron-sized cerium oxide-containing material. The steps a) and b)
can be performed in any order. The variations described above for
the previously described coated substrates are also applicable to
the substrate recited in this method. In any of the disclosed
embodiments, the micron-sized cerium oxide-containing material can
comprise cerium oxide, cerium-zirconium oxide, cerium-lanthanum
oxide, cerium-yttrium oxide, cerium-zirconium-lanthanum oxide,
cerium-zirconium-yttrium oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0.13La.sub.0.04O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide.
[0074] Further described is a method of forming a coated substrate,
the method comprising a) coating a substrate with a washcoat
composition comprising oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles, the oxidative catalytically
active Nano-on-Nano-in-Micro (NNiM) particles comprising composite
nanoparticles embedded in a first micron-sized porous carrier, and
the composite nanoparticles comprising a first support nanoparticle
and an oxidative catalytic nanoparticle; and b) coating the
substrate with a washcoat composition comprising reductive
catalytically active Nano-on-Nano-in-Micro (NNiM) particles and
NO.sub.x trapping particles, the reductive catalytically active
Nano-on-Nano-in-Micro (NNiM) particles comprising composite
nanoparticles embedded in a second micron-sized porous carrier, and
the composite nanoparticles comprising a second support
nanoparticle and an oxidative catalytic nanoparticle, and the
NO.sub.x trapping particles comprising micron-sized cerium oxide or
micron-sized cerium oxide-containing material. The steps a) and b)
can be performed in any order. The variations described above for
the previously described coated substrates are also applicable to
the substrate recited in this method. In any of the disclosed
embodiments, the micron-sized cerium oxide-containing material can
comprise cerium oxide, cerium-zirconium oxide, cerium-lanthanum
oxide, cerium-yttrium oxide, cerium-zirconium-lanthanum oxide,
cerium-zirconium-yttrium oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0.13La.sub.0.04O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide.
[0075] Further described is a method of forming a coated substrate,
the method comprising a) coating a substrate with a washcoat
composition comprising oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles, the oxidative catalytically
active Nano-on-Nano-on-micro (NNm) particles comprising composite
nanoparticles bonded to a first micron-sized carrier particle, and
the composite nanoparticles comprising a first support nanoparticle
and an oxidative catalytic nanoparticle; b) coating the substrate
with a washcoat composition comprising reductive catalytically
active Nano-on-Nano-on-micro (NNm) particles, the reductive
catalytically active Nano-on-Nano-on-micro (NNm) particles
comprising composite nanoparticles bonded to second micron-sized
carrier particle, and the composite nanoparticles comprising a
second support nanoparticle and a reductive catalytic nanoparticle,
and c) and coating the substrate with a washcoat composition
comprising NO.sub.x trapping particles, the NO.sub.x trapping
particles comprising micron-sized cerium oxide or micron-sized
cerium oxide-containing material. The steps a), b), and c) can be
performed in any order. The variations described above for the
previously described coated substrates are also applicable to the
substrate recited in this method. In any of the disclosed
embodiments, the micron-sized cerium oxide-containing material can
comprise cerium oxide, cerium-zirconium oxide, cerium-lanthanum
oxide, cerium-yttrium oxide, cerium-zirconium-lanthanum oxide,
cerium-zirconium-yttrium oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0.13La.sub.0.04O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide.
[0076] Further described is a method of forming a coated substrate,
the method comprising a) coating a substrate with a washcoat
composition comprising oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles, the oxidative catalytically
active Nano-on-Nano-in-Micro (NNiM) particles comprising composite
nanoparticles embedded in a first micron-sized porous carrier, and
the composite nanoparticles comprising a first support nanoparticle
and an oxidative catalytic nanoparticle; b) coating the substrate
with a washcoat composition comprising reductive catalytically
active Nano-on-Nano-in-Micro (NNiM) particles, the reductive
catalytically active Nano-on-Nano-in-Micro (NNiM) particles
comprising composite nanoparticles embedded in a second
micron-sized porous carrier, and the composite nanoparticles
comprising a second support nanoparticle and an oxidative catalytic
nanoparticle and c) coating the substrate with a washcoat
composition comprising NO.sub.x trapping particles, and the
NO.sub.x trapping particles comprising micron-sized cerium oxide or
micron-sized cerium oxide-containing material. The steps a), b),
and c) can be performed in any order. The variations described
above for the previously described coated substrates are also
applicable to the substrate recited in this method. In any of the
disclosed embodiments, the micron-sized cerium oxide-containing
material can comprise cerium oxide, cerium-zirconium oxide,
cerium-lanthanum oxide, cerium-yttrium oxide,
cerium-zirconium-lanthanum oxide, cerium-zirconium-yttrium oxide,
cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0.13La.sub.0.04O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide.
[0077] In any of the disclosed embodiments herein, the cerium
oxide-containing material, including micron-sized cerium
oxide-containing material, can comprise cerium oxide,
cerium-zirconium oxide, cerium-lanthanum oxide, cerium-yttrium
oxide, cerium-zirconium-lanthanum oxide, cerium-zirconium-yttrium
oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In the cerium-zirconium
oxide, cerium can comprise from about 20% to 99%, and zirconium can
comprise from about 1% to 80%, of the cerium-zirconium oxide by
weight of the corresponding pure metal oxides. (That is, were the
mixed metal oxide to be purified into separate oxides, there would
be from about 20% to 99% by weight cerium oxide and from about 1 to
80% by weight zirconium oxide.) In the cerium-zirconium-lanthanum
oxide, cerium can comprise from about 20% to 99%, zirconium can
comprise up to about 1% to about 80%, and lanthanum can comprise up
to about 30% of the cerium-zirconium-lanthanum oxide by weight of
the corresponding pure metal oxides. In the
cerium-zirconium-lanthanum-yttrium oxide, cerium can comprise from
about 20% to 99%, zirconium can comprise up to about 1% to about
80%, lanthanum can comprise up to about 30%, and yttrium can
comprise up to about 30% of the cerium-zirconium-lanthanum-yttrium
oxide by weight of the corresponding pure metal oxides. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises Ce.sub.0.83Zr.sub.0.13La.sub.0.04O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 86% cerium
oxide, 10% zirconium oxide, and 4% lanthanum oxide by the weight of
the corresponding pure metal oxides. In some preferred embodiments,
the micron-sized cerium oxide-containing material comprises
Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 40% cerium oxide, 50%
zirconium oxide, 5% lanthanum oxide, and 5% yttrium oxide by the
weight of the corresponding pure metal oxides.
[0078] In any of the disclosed embodiments, including the foregoing
embodiments, the substrate can comprise cordierite. In any of the
disclosed embodiments, including the foregoing embodiments, the
substrate can comprise a honeycomb structure.
[0079] In any of the disclosed embodiments, including the foregoing
embodiments, the washcoat layer on the coated substrate comprising
oxidative catalytically active Nano-in-Nano-on-micro (NNm)
particles has a thickness of 25 g/L to 150 g/L.
[0080] In any of the disclosed embodiments, including the foregoing
embodiments, the washcoat layer on the coated substrate comprising
reductive catalytically active Nano-in-Nano-on-micro (NNm)
particles has a thickness of 25 g/L to 150 g/L.
[0081] In any of the disclosed embodiments, including the foregoing
embodiments, the washcoat layer on the coated substrate comprising
NO.sub.x trapping particles has a thickness of 100 g/L to 400
g/L.
[0082] In any of the disclosed embodiments, including the foregoing
embodiments, the coated substrate has a platinum group metal
loading of 4 g/L or less and a light-off temperature for carbon
monoxide at least 5.degree. C. lower than the light-off temperature
of a substrate with the same platinum group metal loading deposited
by wet-chemistry methods.
[0083] In any of the disclosed embodiments, including the foregoing
embodiments, the coated substrate has a platinum group metal
loading of about 3.0 g/L to about 5.5 g/L, wherein after 125,000
miles of operation in a vehicular catalytic converter, the coated
substrate has a light-off temperature for carbon monoxide at least
5.degree. C. lower than a coated substrate prepared by depositing
platinum group metals by wet chemical methods having the same
platinum group metal loading after 125,000 miles of operation in a
vehicular catalytic converter.
[0084] In any of the disclosed embodiments, including the foregoing
embodiments, the coated substrate has a platinum group metal
loading of about 3.0 g/L to about 5.5 g/L, wherein after aging for
16 hours at 800.degree. C., the coated substrate has a light-off
temperature for carbon monoxide at least 5.degree. C. lower than a
coated substrate prepared by depositing platinum group metals by
wet chemical methods having the same platinum group metal loading
after aging for 16 hours at 800.degree. C.
[0085] Further described herein is a catalytic converter comprising
a coated substrate of any one of the disclosed embodiments,
including the foregoing embodiments. Further described herein is an
exhaust treatment system comprising a conduit for exhaust gas and
the foregoing catalytic converter. Further described herein is a
vehicle comprising the foregoing catalytic converter.
[0086] Further described herein is a method of treating an exhaust
gas, comprising contacting the coated substrate of any of the
foregoing embodiments with the exhaust gas. In further embodiments,
the substrate can be housed within a catalytic converter configured
to receive the exhaust gas.
BRIEF DESCRIPTION OF THE DRAWINGS
[0087] FIG. 1 illustrates a catalytic converter in accordance with
some embodiments of the present invention.
[0088] FIG. 1A is a magnified view of a portion of the drawing of
FIG. 1 in accordance with some embodiments of the present
invention.
[0089] FIG. 2 is a flow chart illustrating a preparation method of
a coated substrate comprising oxidative catalytically active
particles and reductive catalytically active particles contained in
separate washcoat layers, and the reductive catalytically active
particles and the NO.sub.x storage material contained in a single
washcoat layer, in accordance with some embodiments of the present
invention.
[0090] FIG. 3 is a flow chart illustrating a preparation method of
a coated substrate comprising oxidative catalytically active
particles, reductive catalytically active particles, and the
NO.sub.x storage material contained in separate washcoat layers, in
accordance with some embodiments of the present invention.
[0091] FIG. 4 is a graph comparing the performance of some
embodiments of the present invention (reduced PGM in the NO.sub.x
storage layer; no PGM in the NO.sub.x storage layer) to a standard
commercially available catalytic converter.
[0092] FIG. 5 is a series of graphs comparing A) the total
hydrocarbon content (THC) and B) the NO.sub.x emissions of an
embodiment of the present invention (coated substrate with
three-layer washcoat configuration) to a commercial reference
catalyst and to the Euro 6 light-duty diesel emissions
standard.
DETAILED DESCRIPTION OF THE INVENTION
[0093] Described are LNT systems and methods of making LNT systems
by combining washcoat layers of oxidative catalytically active
particles, reductive catalytically active particles, and NO.sub.x
trapping materials. Also described are composite nanoparticle
catalysts, washcoat formulations, coated substrates, catalytic
converters, and methods of making and using these composite
nanoparticle catalysts, washcoat formulations, coated substrates,
and catalytic converters. The described LNT systems may use a
reduced amount of precious metal relative to typical LNT systems.
Accordingly, these LNT systems may provide a more economical
alternative to commercially available LNTs.
[0094] In addition, the described substrates, composite
nanoparticle catalysts, and washcoat solutions may provide for
comparable or increased performance relative to prior LNTs when
used to produce catalytic converters, allowing for the production
of catalytic converters having reduced light-off temperatures and
reduced emissions using reduced platinum group metal loading
requirements. The described coated substrates include washcoat
layers in which the NO.sub.x trapping particles are composed
entirely of non-PGMs, or a combination of PGM and non-PGM. These
coated substrates can be used to make an effective catalytic
converter in a more economical fashion than has been previously
possible.
[0095] The composite nanoparticles described herein include
catalytic nanoparticles and support nanoparticles that are bonded
together to form nano-on-nano composite nanoparticles. The
composite nanoparticles may be produced, for example, in a plasma
reactor so that consistent and tightly bonded nano-on-nano
composite particles are produced. These composite nanoparticles can
then be bonded to a micron-sized carrier particle to form
micron-sized catalytically active particles
("nano-on-nano-on-micro" particles or NNm particles). The
nano-on-nano composite particles are predominantly located at or
near the surface of the resulting micron-sized particles.
Alternatively, the composite nanoparticles can be embedded within a
porous carrier to produce micron-sized catalytic particles
("nano-on-nano-in-micro" particles or NNiM particles). In this
configuration, the nano-on-nano composite nanoparticles are
distributed throughout the micron-sized carrier particles. Both
types of micron-sized catalytically active particles bearing
composite nanoparticles (i.e., NNm and NNiM) may offer better
initial engine start-up performance, better performance over the
lifetime of the catalyst and/or NO.sub.x storage material, and/or
less decrease in performance over the life of the catalyst and/or
NO.sub.x storage material, as compared to previous catalysts and
NO.sub.x storage materials used in catalytic converters.
[0096] Further, the LNT system can include two or more layers of
washcoats on a catalyst substrate, such as a catalytic converter
substrate. The micron-sized particles bearing composite oxidative
nanoparticles and micron-sized particles bearing composite
reductive nanoparticles are in different washcoat layers. In some
embodiments, the NO.sub.x trapping particles and the micron-sized
particles bearing composite reductive nanoparticles are in the same
washcoat layer. In some embodiments, the NO.sub.x trapping
particles and the micron-sized particles bearing composite
reductive nanoparticles are in separate washcoat layers. When the
NO.sub.x trapping particles and the micron-sized particles bearing
composite reductive nanoparticles are in separate washcoat layers,
the order and placement of these two layers on a substrate may vary
in different embodiments. In some embodiments, additional washcoat
layers may also be used over, under, or between these washcoat
layers. In other embodiments, the two layers can be directly
disposed on each other, without intervening layers between the
first and second washcoat layers.
[0097] The coated substrates, catalytic converters, and exhaust
treatment systems described herein are useful for vehicles
employing a lean NO.sub.x trap (LNT) or NO.sub.x storage catalyst
(NSC) system. It is understood that the coated substrates,
catalytic converters, and exhaust treatment systems described
herein are useful for either gasoline or diesel engines, and either
gasoline or diesel vehicles. These coated substrates, catalytic
converters, and exhaust treatment systems are especially useful for
light-duty engines and light-duty vehicles.
[0098] Various aspects of the disclosure can be described through
the use of flowcharts. Often, a single instance of an aspect of the
present disclosure is shown. As is appreciated by those of ordinary
skill in the art, however, the protocols, processes, and procedures
described herein can be repeated continuously or as often as
necessary to satisfy the needs described herein. In addition, it is
contemplated that certain method steps can be performed in
alternative sequences to those disclosed in the flowcharts.
[0099] When numerical values are expressed herein using the term
"about" or the term "approximately," it is understood that both the
value specified, as well as values reasonably close to the value
specified, are included. For example, the description "about
50.degree. C." or "approximately 50.degree. C." includes both the
disclosure of 50.degree. C. itself, as well as values close to
50.degree. C. Thus, the phrases "about X" or "approximately X"
include a description of the value X itself. If a range is
indicated, such as "approximately 50.degree. C. to 60.degree. C,"
it is understood that both the values specified by the endpoints
are included, and that values close to each endpoint or both
endpoints are included for each endpoint or both endpoints; that
is, "approximately 50.degree. C. to 60.degree. C." is equivalent to
reciting both "50.degree. C. to 60.degree. C." and "approximately
50.degree. C. to approximately 60.degree. C."
[0100] Percentages of materials represent weight percentages,
unless otherwise specified.
[0101] By "substantial absence of any platinum group metals" is
meant that less than about 5%, less than about 2%, less than about
1%, less than about 0.5%, less than about 0.1%, less than about
0.05%, less than about 0.025%, or less than about 0.01% of platinum
group metals are present by weight. Preferably, substantial absence
of any platinum group metals indicates that less than about 1% of
platinum group metals are present by weight.
[0102] By "substantially free of" a specific component, a specific
composition, a specific compound, or a specific ingredient in
various embodiments, is meant that less than about 5%, less than
about 2%, less than about 1%, less than about 0.5%, less than about
0.1%, less than about 0.05%, less than about 0.025%, or less than
about 0.01% of the specific component, the specific composition,
the specific compound, or the specific ingredient is present by
weight. Preferably, "substantially free of" a specific component, a
specific composition, a specific compound, or a specific ingredient
indicates that less than about 1% of the specific component, the
specific composition, the specific compound, or the specific
ingredient is present by weight.
[0103] It should be noted that, during fabrication or during
operation (particularly over long periods of time), small amounts
of materials present in one washcoat layer may diffuse, migrate, or
otherwise move into other washcoat layers. Accordingly, use of the
terms "substantial absence of" and "substantially free of" is not
to be construed as absolutely excluding minor amounts of the
materials referenced.
[0104] By "substantially each" of a specific component, a specific
composition, a specific compound, or a specific ingredient in
various embodiments, is meant that at least about 95%, at least
about 98%, at least about 99%, at least about 99.5%, at least about
99.9%, at least about 99.95%, at least about 99.975%, or at least
about 99.99% of the specific component, the specific composition,
the specific compound, or the specific ingredient is present by
number or by weight. Preferably, "substantially each" of a specific
component, a specific composition, a specific compound, or a
specific ingredient is meant that at least about 99% of the
specific component, the specific composition, the specific
compound, or the specific ingredient is present by number or by
weight.
[0105] By "reductive catalytic nanoparticle" is meant a
nanoparticle that catalyzes a reducing reaction, especially the
reduction of NO.sub.x (such as NO.sub.2) to N.sub.2 and H.sub.2O.
Most commonly, the reductive catalytic nanoparticle comprises
rhodium. Under appropriate operating conditions, such as a
fuel-rich "purge" cycle (where fuel is in stoichiometric excess
relative to oxygen), rhodium catalyzes the reduction of NO.sub.x
(such as NO.sub.2) to N.sub.2 and H.sub.2O.
[0106] By "oxidative catalytic nanoparticle" is meant a
nanoparticle that catalyzes an oxidation reaction, especially the
oxidation of hydrocarbons (such as the unburnt hydrocarbons in the
exhaust stream of a combustion engine) to CO.sub.2 and H.sub.2O,
and/or the oxidation of CO (such as occurs in the exhaust stream of
a combustion engine) to CO.sub.2. Most commonly, the oxidative
catalytic nanoparticle comprises platinum, palladium, combinations
of platinum or palladium, or a platinum/palladium alloy. Under
appropriate operating conditions, such as a fuel-lean "NO.sub.x
storage" cycle (where oxygen is in stoichiometric excess relative
to fuel), platinum, palladium, combinations of platinum and
palladium, or a platinum/palladium alloy catalyze the oxidation of
hydrocarbons to CO.sub.2 and H.sub.2O, and/or the oxidation of CO
to CO.sub.2. The oxidative catalytic nanoparticle can also oxidize
NO to NO.sub.2, as NO.sub.2 may be easier to store temporarily than
NO.
[0107] By "NO.sub.x trapping particle" or "NO.sub.x storage
particle" is meant a particle capable of storing NO.sub.x (such as
NO.sub.2) during a fuel-lean NO.sub.x storage cycle, while
releasing NOx (such as NO.sub.2) during a fuel-rich NO.sub.x (or
NO.sub.2) purge cycle.
[0108] This disclosure provides several embodiments. It is
contemplated that any features from any embodiment can be combined
with any features from any other embodiment. In this fashion,
hybrid configurations of the disclosed features are within the
scope of the present invention. For the avoidance of doubt, it is
confirmed that in the general description herein, in the usual way,
features described as part of "one" embodiment or "some"
embodiments are generally combinable with features of another
embodiment, in so far as they are compatible.
[0109] It is understood that reference to relative weight
percentages in a composition assumes that the combined total weight
percentages of all components in the composition add up to 100. It
is further understood that relative weight percentages of one or
more components may be adjusted upwards or downwards such that the
weight percent of the components in the composition combine to a
total of 100, provided that the weight percent of any particular
component does not fall outside the limits of the range specified
for that component.
[0110] This disclosure refers to both particles and powders. These
two terms are equivalent, except for the caveat that a singular
"powder" refers to a collection of particles. The present invention
can apply to a wide variety of powders and particles. The terms
"nanoparticle" and "nano-sized particle" are generally understood
by those of ordinary skill in the art to encompass a particle on
the order of nanometers in diameter, typically between about 0.5 nm
to 500 nm, about 1 nm to 500 nm, about 1 nm to 100 nm, or about 1
nm to 50 nm. Preferably, the nanoparticles have an average grain
size less than 250 nanometers and an aspect ratio between one and
one million. In some embodiments, the nanoparticles have an average
grain size of about 50 nm or less, about 30 nm or less, or about 20
nm or less. In additional embodiments, the nanoparticles have an
average diameter of about 50 nm or less, about 30 nm or less, or
about 20 nm or less. The aspect ratio of the particles, defined as
the longest dimension of the particle divided by the shortest
dimension of the particle, is preferably between one and one
hundred, more preferably between one and ten, yet more preferably
between one and two. "Grain size" is measured using the AS.TM.
(American Society for Testing and Materials) standard (see ASTM
E112-10). When calculating a diameter of a particle, the average of
its longest and shortest dimension is taken; thus, the diameter of
an ovoid particle with long axis 20 nm and short axis 10 nm would
be 15 nm. The average diameter of a population of particles is the
average of diameters of the individual particles, and can be
measured by various techniques known to those of skill in the
art.
[0111] In additional embodiments, the nanoparticles have a grain
size of about 50 nm or less, about 30 nm or less, or about 20 nm or
less. In additional embodiments, the nanoparticles have a diameter
of about 50 nm or less, about 30 nm or less, or about 20 nm or
less.
[0112] The terms "micro-particle," "micro-sized particle,"
"micron-particle," and "micron-sized particle" are generally
understood to encompass a particle on the order of micrometers in
diameter, typically between about 0.5 .mu.m to 1000 .mu.m, about 1
.mu.m to 1000 .mu.m, about 1 .mu.m to 100 .mu.m, or about 1 .mu.m
to 50 .mu.m. Additionally, the term "platinum group metals"
(abbreviated "PGM") used in this disclosure refers to the
collective name used for six metallic elements clustered together
in the periodic table. The six platinum group metals are ruthenium,
rhodium, palladium, osmium, iridium, and platinum.
Composite Nanoparticle Catalyst
[0113] LNTs may include three different types of composite
nanoparticles. One type of composite nanoparticle is an oxidative
composite nanoparticle. A second type of composite nanoparticle is
a reductive composite nanoparticle. A third type of composite
nanoparticle is an NO.sub.x trapping composite nanoparticle.
[0114] A composite nanoparticle catalyst may include a catalytic
nanoparticle attached to a support nanoparticle to form a
"nano-on-nano" composite nanoparticle. Multiple nano-on-nano
particles may then be bonded to or embedded in a micron-sized
carrier particle to form a composite micro/nanoparticle, that is, a
micro-particle bearing composite nanoparticles. These composite
micro/nanoparticles may be used in washcoat formulations and
catalytic converters as described herein. The use of these
particles can reduce requirements for platinum group metal content
and/or significantly enhance performance, particularly in terms of
reduced light-off temperature, as compared with currently available
commercial catalytic converters prepared by wet-chemistry methods.
The wet-chemistry methods generally involve use of a solution of
platinum group metal ions or metal salts, which are impregnated
into supports (typically micron-sized particles), and reduced to
platinum group metal in elemental form for use as the catalyst. For
example, a solution of chloroplatinic acid, H.sub.2PtCl.sub.6, can
be applied to alumina micro-particles, followed by drying and
calcining, resulting in precipitation of platinum onto the alumina.
The platinum group metals deposited by wet-chemical methods onto
metal oxide supports, such as alumina and cerium oxide, are mobile
at high temperatures, such as temperatures encountered in catalytic
converters. That is, at elevated temperatures, the PGM atoms can
migrate over the surface on which they are deposited, and will
clump together with other PGM atoms. The finely-divided portions of
PGM combine into larger and larger agglomerations of platinum group
metal as the time of exposure to high temperature increases. This
agglomeration leads to reduced catalyst surface area and degrades
the performance of the catalytic converter. This phenomenon is
referred to as "aging" of the catalytic converter.
[0115] In contrast, the composite platinum group metal catalysts
are prepared by plasma-based methods. In one embodiment, the
platinum group nano-sized metal particle is deposited on a
nano-sized metal oxide support, which has much lower mobility than
the PGM deposited by wet chemistry methods. The resulting
plasma-produced catalysts age at a much slower rate than the
catalysts produced by wet-chemistry. Thus, catalytic converters
using plasma-produced catalysts can maintain a larger surface area
of exposed catalyst to gases emitted by the engine over a longer
period of time, leading to better emissions performance.
[0116] Impregnation of a support, such as a micron-sized support,
using wet-chemistry methods tends to deposit the material
throughout the material, that is, deep into the interior of the
material. For example, applying a solution of chloroplatinic acid
to a micron-sized aluminum oxide particle will result in
penetration of the solution throughout the particle. When followed
by drying and calcining, platinum precipitates from solution onto
the alumina in finely-divided portions (typically on the order of
tenths of nanometers, i.e., clusters of a few atoms, or on the
order of nanometers) throughout the entire volume of the particle.
Thus, a support impregnated with a metal salt via wet-chemistry
methods will have material distributed substantially evenly
throughout the volume of the support, or at the very least
throughout the volume of the particle accessible to the metal salt
solution.
[0117] In contrast, impregnation of a support, such as a
micron-sized support, with composite nanoparticles ("nano-on-nano"
or "NN" particles) tends to result in the catalytic material
distributed primarily on or near the surface of the support
particle. As the nano-on-nano particles are applied to the support
particle in a suspension, they cannot penetrate as deeply into the
interior of the support particle as the solution of metal salt used
in the wet-chemistry methods, resulting in an "eggshell"
distribution, where a thin layer of NN particles coats the surface
(and the pores closest to the surface) of the support. Thus, the
majority of NN particles tend to be located on or near the surface
of the support. The NN particles cannot penetrate into pores of the
support which are not large enough to accept the NN particles, and
are restricted to the exterior surface, and the interior portions
of the support particle that are accessible to the NN particles.
The nano-on-nano-on-micro ("NNm") particles thus have composite
nanoparticles distributed on the exterior surface and on the
nano-on-nano accessible interior surface of the micron-sized
support particle.
[0118] The nano-on-nano-in-micro (NNiM) particles described herein,
and described in more detail in co-owned U.S. Provisional Patent
Application No. 61/881,337 filed Sep. 23, 2013, U.S. patent
application Ser. No. 14/494,156 filed Sep. 23, 2014, and
International Patent Appl. No. PCT/US2014/057036 filed Sep. 23,
2014, the disclosures of which are hereby incorporated by reference
in their entirety, were designed in order to remedy the uneven
distribution of the composite nanoparticles on the micron-sized
support. By forming a matrix of the support material around the
composite nanoparticles (nano-on-nano or "NN" particles), the
composite nanoparticles can be substantially evenly distributed
throughout the support material. The support material containing
the composite nanoparticles can be milled or ground to the desired
micron-sized dimension, thus creating a micron-sized support
particle with a substantially uniform distribution of composite
nanoparticles throughout its entire volume. This
nano-on-nano-IN-micro (NNiM) configuration permits loading much
more catalyst per unit volume of support material (i.e., per unit
volume of micron-sized support particle) than the
nano-on-nano-ON-micro (NNm) configuration.
Oxidative Composite Nanoparticle (Oxidative "Nano-on-Nano"
Particle)
[0119] As discussed above, one type of composite nanoparticle is an
oxidative composite nanoparticle catalyst. An oxidative composite
nanoparticle may include one or more oxidative catalyst
nanoparticles attached to a first support nanoparticle to form an
oxidative "nano-on-nano" composite nanoparticle. Platinum (Pt) and
palladium (Pd) are oxidative to the hydrocarbon gases and carbon
monoxide. In certain embodiments, the oxidative nanoparticle is
platinum. In other embodiments, the oxidative nanoparticle is
palladium. In some embodiments, the oxidative nanoparticle is a
mixture of platinum and palladium. A suitable support nanoparticle
for the oxidative catalyst nanoparticle includes, but is not
limited to, nano-sized aluminum oxide (alumina or
Al.sub.2O.sub.3).
[0120] Each oxidative catalyst nanoparticle may be supported on a
first support nanoparticle. The first support nanoparticle may
include one or more oxidative nanoparticles. The oxidative catalyst
nanoparticles on the first support nanoparticle may include
platinum, palladium, or a mixture thereof. At the high temperatures
involved in gasoline or diesel exhaust engines, both palladium and
platinum are effective oxidative catalysts. Accordingly, in some
embodiments, the oxidative catalyst is palladium alone. In other
embodiments, platinum may be used alone. In further embodiments,
platinum may be used in combination with palladium. For example,
the first support nanoparticle may contain a mixture of 5:1 to
100:1 platinum to palladium. In some embodiments, the first support
nanoparticle may contain a mixture of 6:1 to 75:1 platinum to
palladium. In some embodiments, the first support nanoparticle may
contain a mixture of 7:1 to 50:1 platinum to palladium. In some
embodiments, the first support nanoparticle may contain a mixture
of 8:1 to 25:1 platinum to palladium. In some embodiments, the
first support nanoparticle may contain a mixture of 9:1 to 15:1
platinum to palladium. In some embodiments, the first support
nanoparticle may contain a mixture of 10:1 platinum to palladium,
or approximately 10:1 platinum to palladium.
Reductive Composite Nanoparticle (Reductive "Nano-on-Nano"
Particle)
[0121] As discussed above, another type of composite nanoparticle
is a reductive composite nanoparticle catalyst. A reductive
composite nanoparticle may include one or more reductive catalyst
nanoparticles attached to a second support nanoparticle to form a
reductive "nano-on-nano" composite nanoparticle. Rhodium (Rh) is
reductive to the nitrogen oxides in fuel-rich conditions. In
certain embodiments, the reductive catalyst nanoparticle is
rhodium. The second support may be the same or different than the
first support. A suitable second support nanoparticle for the
reductive nanoparticle includes, but is not limited to, nano-sized
cerium oxide (CeO.sub.2). The nano-sized cerium oxide particles may
contain zirconium oxide. In a preferred embodiment, the nano-sized
cerium oxide particles are substantially free of zirconium oxide.
In other embodiments, the nano-sized cerium oxide particles contain
up to 60% zirconium oxide. In some embodiments, the nano-sized
cerium oxide particles may contain both zirconium oxide and
lanthanum. In some embodiments, the nano-sized cerium oxide
particles contain 40-80% cerium oxide, 10-50% zirconium oxide, and
10% lanthanum oxide. In one embodiment, the nano-sized cerium oxide
particles contain 80% cerium oxide, 10% zirconium oxide, and 10%
lanthanum oxide. In another embodiment, the nano-sized cerium oxide
particles contain 40% cerium oxide, 50% zirconium oxide, and 10%
lanthanum oxide. In another embodiment, the second support
nanoparticle for the reductive nanoparticle comprises cerium oxide,
cerium-zirconium oxide, cerium-lanthanum oxide, cerium-yttrium
oxide, cerium-zirconium-lanthanum oxide, cerium-zirconium-yttrium
oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide, such as
Ce.sub.0.83Zr.sub.0.13La.sub.0.04O, a material that comprises about
86% cerium oxide, 10% zirconium oxide, and 4% lanthanum oxide,
Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O, or a material that
comprises about 40% cerium oxide, 50% zirconium oxide, 5% lanthanum
oxide, and 5% yttrium oxide. (Percentages are weight percent.)
[0122] Each reductive catalyst nanoparticle may be supported on a
second support nanoparticle. The second support nanoparticle may
include one or more reductive catalyst nanoparticles. The ratios of
rhodium to cerium oxide or other support and sizes of the reductive
composite nanoparticle catalyst are further discussed below in the
sections describing production of composite nanoparticles by
plasma-based methods and production of micron-sized carrier
particles bearing composite nanoparticles.
Production of Composite Nanoparticles by Plasma-based Methods
("Nano-on-Nano" Particles or "NN" Particles)
[0123] The oxidative composite nanoparticle catalysts and reductive
composite nanoparticle catalysts can be produced by plasma-based
methods, that is, they can be plasma-generated. These particles
have many advantageous properties as compared to catalysts produced
by wet chemistry. For example, the metals in the composite
nanoparticle catalysts are relatively less mobile under the high
temperature environment of a catalytic converter than the metals in
washcoat mixtures used in typical commercial catalytic converters
produced using wet chemistry methods.
[0124] The oxidative composite nanoparticle catalysts, reductive
composite nanoparticle catalysts, and NO.sub.x trapping composite
nanoparticles may be formed by plasma reactor methods. These
methods include feeding metal(s) and support material into a plasma
gun, where the materials are vaporized. Plasma guns such as those
disclosed in U.S. Patent Publication No. 2011/0143041 can be used,
and techniques such as those disclosed in U.S. Pat. No. 5,989,648,
U.S. Pat. No. 6,689,192, U.S. Pat. No. 6,755,886, and U.S. Patent
Publication No. 2005/0233380, the entire disclosures of which are
hereby incorporated by reference herein, can be used to generate
plasma. The high-throughput system disclosed in U.S. Published
Patent Application No. 2014/0263190 and International Patent
Application No. PCT/US2014/024933 (published as WO 2014/159736),
the entire disclosures of which are hereby incorporated by
reference herein, can be used to generate the composite
nanoparticles. A working gas, such as argon, is supplied to the
plasma gun for the generation of plasma. In one embodiment, an
argon/hydrogen mixture (for example, in the ratio of 10:2
Ar/H.sub.2 or 10:1 Ar/H.sub.2) may be used as the working gas.
[0125] The platinum group metal or metals (such as platinum,
palladium, a mixture of platinum/palladium in any ratio, such as
5:1 up to 100:1 Pt:Pd by weight, rhodium, or ruthenium) generally
in the form of metal particles of about 1 to 6 microns in diameter,
can be introduced into the plasma reactor as a fluidized powder in
a carrier gas stream such as argon. Metal oxide, typically aluminum
oxide or cerium oxide with a particle size of about 15 to 25
microns diameter, is also introduced as a fluidized powder in
carrier gas. However, other methods of introducing the materials
into the reactor can be used, such as in a liquid slurry.
Typically, for oxidative composite nanoparticles, palladium,
platinum, or a mixture thereof is deposited on aluminum oxide.
Typically, for reductive composite nanoparticles, rhodium is
deposited on cerium oxide. However, rhodium can be deposited on
other materials, such as a material that comprises cerium oxide,
cerium-zirconium oxide, cerium-lanthanum oxide, cerium-yttrium
oxide, cerium-zirconium-lanthanum oxide, cerium-zirconium-yttrium
oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide, such as
Ce.sub.0.83Zr.sub.0.13La.sub.0.04O, a material that comprises about
86% cerium oxide, 10% zirconium oxide, and 4% lanthanum oxide,
Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O, or a material that
comprises about 40% cerium oxide, 50% zirconium oxide, 5% lanthanum
oxide, and 5% yttrium oxide.
[0126] For preparation of oxidative composite nanoparticles, a
composition of 1% to 5% platinum group metal(s) and 55% to 99%
metal oxide (by weight) is typically used. Examples of ranges of
materials that can be used for oxidative composite nanoparticles in
which palladium is the oxidation catalyst are from about 1% to 20%
palladium, to 80% to 99% aluminum oxide; and 5% to 20% palladium to
80% to 95% aluminum oxide. Examples of ranges of materials that can
be used for oxidative composite nanoparticles in which platinum is
the oxidation catalyst are from about 35% to 45% platinum to 55% to
65% aluminum oxide. Examples of ranges of materials that can be
used for oxidative composite nanoparticles in which both platinum
and palladium are the oxidation catalyst are from about 23.3% to
about 30% platinum, 11.7% to 15% palladium, and 55% to 65% aluminum
oxide. In a certain embodiment, a composition contains about 26.7%
platinum, 13.3% palladium, and 60% aluminum oxide.
[0127] The oxidative composite nanoparticles may contain a mixture
of 5:1 to 100:1 platinum to palladium. In some embodiments, the
oxidative composite nanoparticles may contain a mixture of 6:1 to
75:1 platinum to palladium. In some embodiments, the oxidative
composite nanoparticles may contain a mixture of 7:1 to 50:1
platinum to palladium. In some embodiments, the oxidative composite
nanoparticles may contain a mixture of 8:1 to 25:1 platinum to
palladium. In some embodiments, the oxidative composite
nanoparticles may contain a mixture of 9:1 to 15:1 platinum to
palladium. In some embodiments, the oxidative composite
nanoparticles may contain a mixture of 10:1 platinum to palladium,
or approximately 10:1 platinum to palladium.
[0128] Examples of ranges of materials that can be used for
reductive composite nanoparticles are from about 1% to about 10%
rhodium and 90% to 99% cerium oxide or cerium oxide-containing
material. In one embodiment, the composition contains about 5%
rhodium and 95% cerium oxide. In any of these embodiments, the
micron-sized cerium oxide-containing material can comprise cerium
oxide, cerium-zirconium oxide, cerium-lanthanum oxide,
cerium-yttrium oxide, cerium-zirconium-lanthanum oxide,
cerium-zirconium-yttrium oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0.13La.sub.004O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide.
[0129] In a plasma reactor, any solid or liquid materials are
rapidly vaporized or turned into plasma. The kinetic energy of the
superheated material, which can reach temperatures of 20,000 to
30,000 Kelvin, ensures extremely thorough mixture of all
components.
[0130] The superheated material of the plasma stream is then
rapidly quenched, using methods such as the turbulent quench
chamber disclosed in U.S. Publication No. 2008/0277267. Argon
quench gas at high flow rates, such as 2400 to 2600 liters per
minute, may be injected into the superheated material. The material
may be further cooled in a cool-down tube, and collected and
analyzed to ensure proper size ranges of material.
[0131] The plasma production method described above produces highly
uniform composite nanoparticles, where the composite nanoparticles
comprise a catalytic nanoparticle bonded to a support nanoparticle.
The catalytic nanoparticle comprises the platinum group metal or
metals, such as Pd, Pt, or Rh. In some embodiments, the catalytic
nanoparticles have an average diameter or average grain size
between approximately 0.3 nm and approximately 10 nm, preferably
between approximately 1 nm to approximately 5 nm, that is,
approximately 3 nm .+-.2 nm. In some embodiments, the support
nanoparticles, comprising the metal oxide such as aluminum oxide or
cerium oxide, have an average diameter of approximately 20 nm or
less, or approximately 15 nm or less, or between approximately 10
nm and approximately 20 nm, that is, approximately 15 nm.+-.5 nm,
or between approximately 10 nm and approximately 15 nm, that is,
approximately 12.5 nm.+-.2.5 nm. In some embodiments, the support
nanoparticles, comprising the metal oxide such as aluminum oxide or
cerium oxide, have a diameter of approximately 20 nm or less, or
approximately 15 nm or less, or between approximately 10 nm and
approximately 20 nm, that is, approximately 15 nm.+-.5 nm, or
between approximately 10 nm and approximately 15 nm, that is,
approximately 12.5 nm.+-.2.5 nm. In one preferred combination, the
catalytic nanoparticles have an average diameter between
approximately 1 nm to approximately 5 nm, and the support
nanoparticles have an average diameter between approximately 10 nm
and approximately 20 nm. In another combination, the catalytic
nanoparticles have an average diameter between approximately 0.3 nm
to approximately 10 nm, and the support nanoparticles have an
average diameter between approximately 10 nm and approximately 20
nm.
[0132] The Pd-alumina, Pt-alumina, and Pt/Pd-alumina composite
nanoparticles, when produced under reducing conditions, such as by
using argon/hydrogen working gas, results in a partially reduced
alumina surface on the support nanoparticle to which the PGM
nanoparticle is bonded, as described in U.S. Publication No.
2011/0143915 at paragraphs 0014-0022. The partially reduced alumina
surface, or Al.sub.2O.sub.(3-x) where x is greater than zero but
less than three, inhibits migration of the platinum group metal on
the alumina surface at high temperatures. This, in turn, limits the
agglomeration of platinum group metal when the particles are
exposed to prolonged elevated temperatures. Such agglomeration is
undesirable for many catalytic applications, as it reduces the
surface area of PGM catalyst available for reaction.
[0133] The composite nanoparticles comprising two nanoparticles
(catalytic and support) are referred to as "nano-on-nano" particles
or "NN" particles.
Production of Micron-sized Carrier Particles Bearing Composite
Nanoparticles ("Nano-on-Nano-on-Micro" Particles or "NNm".TM.
Particles)
[0134] The composite nanoparticles (nano-on-nano particles) may be
further bonded to micron-sized carrier particles to produce
composite micro/nanoparticles, referred to as
"nano-on-nano-on-micro" particles or "NNm".TM. particles, which are
catalytically active particles.
[0135] An oxidative catalytically active particle includes an
oxidative catalyst nanoparticle (such as palladium, platinum, or a
mixture thereof) and nano-sized metal oxide (such as nano-sized
aluminum oxide) which are bonded to a micron-sized carrier particle
(such as micron-sized aluminum oxide). A reductive catalytically
active particle includes a reductive catalyst nanoparticle (such as
rhodium) and a nano-sized metal oxide (such as nano-sized cerium
oxide) which are bonded to micron-sized carrier particles (such as
micron-sized cerium oxide or micron-sized cerium oxide-containing
material).
[0136] The micron-sized particles can have an average size between
about 1 micron and about 100 microns, such as between about 1
micron and about 10 microns, between about 3 microns and about 7
microns, or between about 4 microns and about 6 microns. In one
preferred embodiment, the catalytic nanoparticles have an average
diameter between approximately 1 nm to approximately 5 nm, the
support nanoparticles have an average diameter between
approximately 10 nm and approximately 20 nm, and the micron-sized
particles have an average diameter between approximately 1 micron
and 10 microns. In another embodiment, the catalytic nanoparticles
have an average diameter between approximately 0.3 nm to
approximately 10 nm, the support nanoparticles have an average
diameter between approximately 10 nm and approximately 20 nm, and
the micron-sized particles have an average diameter between
approximately 1 micron and 10 microns.
[0137] In general, the nano-on-nano-on-micro particles are produced
by a process of suspending the composite nanoparticles
(nano-on-nano particles) in water, adjusting the pH of the
suspension to between about 2 and about 7, between about 3 and
about 5, or about 4, adding one or more surfactants to the
suspension (or, alternatively, adding the surfactants to the water
before suspending the composite nanoparticles in the water) to form
a first solution. The process includes sonicating the composite
nanoparticle suspension and applying the suspension to micron-sized
metal oxide particles until the point of incipient wetness, thereby
impregnating the micron-sized particles with composite
nanoparticles and nano-sized metal oxide.
[0138] In some embodiments, the micron-sized metal oxide particles
are pre-treated with a gas at high temperature. The pre-treatment
of the micron-sized metal oxide particles allows the
nano-on-nano-on-micro particles to withstand the high temperatures
of an engine. Without pre-treatment, the nano-on-nano-on-micro
particles would more likely change phase on exposure to high
temperature, compared to the nano-on-nano-on-micro particles that
have been pretreated. In some embodiments, pre-treatment includes
exposure of the micron-sized metal oxide particles at temperatures,
such as about 700.degree. C. to about 1500.degree. C.; 700.degree.
C. to about 1400.degree. C.; 700.degree. C. to about 1300.degree.
C.; and 700.degree. C. to about 1200.degree. C. In some
embodiments, pre-treatment includes exposure of the micron-sized
metal oxide particles at temperatures, such as about 700.degree.
C., 1110.degree. C., 1120.degree. C., 1130.degree. C., 1140.degree.
C., 1150.degree. C., 1155.degree. C., 1160.degree. C., 1165.degree.
C., 1170.degree. C., 1175.degree. C, 1180.degree. C., 1190.degree.
C., and 1200.degree. C.
[0139] The process includes drying the micron-sized metal oxide
particles which have been impregnated with composite nanoparticles
and nano-sized metal oxide, and calcining the micron-sized metal
oxide particles which have been impregnated with composite
nanoparticles and nano-sized metal oxide.
[0140] Typically, the composite nanoparticles and nano-sized metal
oxide are suspended in water, and the suspension is adjusted to
have a pH of between about 2 and about 7, preferably between about
3 and about 5, more preferably a pH of about 4 (the pH is adjusted
with acetic acid or another organic acid). Dispersants and/or
surfactants may be added to the composite nanoparticles and
nano-sized metal oxide. Surfactants suitable for use include
Jeffsperse.RTM. X3202 (Chemical Abstracts Registry No. 68123-18-2,
described as 4,4'-(1-methylethylidene)bis-phenol polymer with
2-(chloromethyl)oxirane, 2-methyloxirane, and oxirane),
Jeffsperse.RTM. X3204, and Jeffsperse.RTM. X3503 surfactants from
Huntsman (JEFFSPERSE is a registered trademark of Huntsman
Corporation, The Woodlands, Tex., United States of America for
chemicals for use as dispersants and stabilizers), which are
non-ionic polymeric dispersants. Other suitable surfactants include
Solsperse.RTM. 24000 and Solsperse.RTM. 46000 from Lubrizol
(SOLSPERSE is a registered trademark of Lubrizol Corporation,
Derbyshire, United Kingdom for chemical dispersing agents). The
Jeffsperse.RTM. X3202 surfactant, Chemical Abstracts Registry No.
68123-18-2 (described as 4,4'-(1-methylethylidene)bis-phenol
polymer with 2-(chloromethyl)oxirane, 2-methyloxirane, and
oxirane), is preferred. The surfactant may be added in a range, for
example, of about 0.5% to about 5%, with about 2% being a typical
value.
[0141] The mixture of aqueous surfactants, composite nanoparticles,
and nano-sized metal oxide may be sonicated to disperse the
composite nanoparticles and nano-sized metal oxide. The quantity of
composite nanoparticles and nano-sized metal oxide in the
dispersion may be in the range of about 2% to about 15% (by mass).
General Procedures for Preparation of Catalysts for Oxidation
Reaction (Oxidative "Nano-on-Nano-on-Micro" Particles or "NNm".TM.
Particles)
[0142] To prepare an oxidative catalytically active particle, a
dispersion of oxidative composite nanoparticles may be applied to
porous, micron-sized Al.sub.2O.sub.3, which may be purchased, for
example, from companies such as Rhodia or Sasol. The porous,
micron-sized, Al.sub.2O.sub.3 powders may be stabilized with a
small percentage of lanthanum (about 2% to about 4% La). One
commercial alumina powder suitable for use is MI-386, which may be
purchased from Grace Davison or Rhodia. The usable surface for this
powder, defined by pore sizes greater than 0.28 .mu.m, is
approximately 2.8 m.sup.2/g. The ratio of composite nanoparticles
used to micron-sized carrier particles used may be from about 3:100
to about 10:100, about 5:100 to about 8:100, or about 6.5:100, in
terms of (weight of composite nanoparticle):(weight of micron
carrier particle). In some embodiments, about 8 grams of composite
nanoparticles may be used with about 122 grams of carrier
micro-particles. The aqueous dispersion of composite nanoparticles
may be applied in small portions (such as by dripping or other
methods) to the micron-sized powder until the point of incipient
wetness, producing a material similar to damp sand as described
below.
[0143] In some instances, the sizes of the nano-sized oxidative
catalysts, for example Pd, Pt, or Pt/Pd are about 1 nm and the
sizes of the nano-sized Al.sub.2O.sub.3 are about 10 nm. In some
instances, the sizes of the nano-sized oxidative catalysts are
approximately 1 nm or less and the sizes of the nano-sized
Al.sub.2O.sub.3 are approximately 10 nm or less. In some instances,
Pd is used as the oxidative catalyst and the weight ratio of
nano-sized Pd: nano-sized aluminum oxide is about 5%:95%. In some
instances, the weight percentage of nano-sized Pd is between about
5% to about 20% of nano-sized Pd on nano-sized aluminum oxide. The
nano-on-nano material that contains nano-sized Pd on nano-sized
Al.sub.2O.sub.3 shows a dark black color. In some instances, Pt is
used as the oxidative catalyst and the weight ratio of nano-sized
Pt:nano-sized aluminum oxide is about 40%:60%. In some instances, a
mixture of Pt and Pd is used as the oxidative catalyst. In some
embodiments, the weight ratio of nano-sized Pt/Pd:nano-sized
aluminum oxide is about 5%:95%. In some embodiments, the weight
ratio of nano-sized Pt/Pd:nano-sized aluminum oxide is about
10%:90%. In some embodiments, the weight ratio of nano-sized
Pt/Pd:nano-sized aluminum oxide is about 20%:80%. In some
embodiments, the weight ratio of nano-sized Pt/Pd:nano-sized
aluminum oxide is about 30%:70%. In some embodiments, the weight
ratio of nano-sized Pt/Pd:nano-sized aluminum oxide is about
40%:60%.
[0144] A solution containing dispersed nano-on-nano material can be
prepared using a sonication process to disperse nano-on-nano
particles into water with pH .about.4. Subsequently, 100 g of
micron-sized MI-386 Al.sub.2O.sub.3 is put into a mixer, and a 100
g dispersion containing the nano-on-nano material is injected into
the mixing aluminum oxide. This process is referred to as the
incipient wetness process or method.
[0145] Next, the wet powder is dried at 60.degree. C. in a
convection oven overnight until it is fully dried. Once the powder
is dried, calcination is performed. The dried powder from the
previous step, that is, the nanomaterials on the micron-sized
material, is baked at 550.degree. C. for two hours under ambient
air conditions. During the calcination, the surfactant is burned
off and the nanomaterials are glued or fixed onto the surface of
the micron-sized materials or onto the surface of the pores of the
micron-materials. One explanation for why the nanomaterials can be
glued or fixed more permanently onto the micron-sized material
during the calcination is because oxygen-oxygen (O--O) bonds,
oxide-oxide bonds, or covalent bonds are formed during the
calcination step. The oxide-oxide bonds can be formed between the
nanomaterials (nano-on-nano with nano-on-nano, nano-on-nano with
nano-sized aluminum oxide, and nano-sized aluminum oxide with
nano-sized aluminum oxide), between the nanomaterials and the
micron-sized materials, and between the micron-sized materials
themselves. The oxide-oxide bond formation is sometimes referred to
as a solid state reaction. At this stage, the material produced
contains a micron-sized particle having nano-on-nano and nano-sized
Al.sub.2O.sub.3 randomly distributed on the surface.
[0146] The oxidative NNm.TM. particles may contain from about 0.5%
to about 5% palladium by weight, or in another embodiment from
about 1% to 3% by weight, or in another embodiment, about 1.2% to
2.5% by weight, of the total mass of the NNm.TM. particle. The
oxidative NNm.TM. particles may contain from about 1% to about 6%
platinum by weight, of the total mass of the NNm.TM. particle. The
oxidative NNm.TM. particles may contain from about 1% to about 6%
platinum/palladium by weight, or in another embodiment, about 2% to
3% by weight, of the total mass of the NNm.TM. particle.
General Procedures for Preparation of Catalysts for Reduction
Reaction (Reductive "Nano-on-Nano-on-Micro" Particles or "NNm".TM.
Particles)
[0147] To prepare a reductive catalytically active particle, a
dispersion of reductive composite nanoparticles may be applied to
porous, micron-sized cerium oxide or micron-sized cerium
oxide-containing material, which may be purchased, for example,
from companies such as Rhodia-Solvay or Sigma-Aldrich, or prepared
as desired using methods analogous to those known in the art (see,
e.g., Rossignol et al., J. Mater. Chem. 9:1615 (1999)). One
commercial cerium oxide powder suitable for use is HSA5, available
from Rhodia-Solvay. The micron-sized cerium oxide may contain
zirconium oxide. In some embodiments, the micron-sized cerium oxide
is substantially free of zirconium oxide. In some embodiments, the
micron-sized cerium oxide-containing material comprises cerium
oxide, cerium-zirconium oxide, cerium-lanthanum oxide,
cerium-yttrium oxide, cerium-zirconium-lanthanum oxide,
cerium-zirconium-yttrium oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.-0.13La.sub.0.04O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide.
[0148] In one embodiment, the reductive composite nanoparticle
comprises rhodium; that is, the reductive catalytic nanoparticle
comprises rhodium. Under appropriate operating conditions, such as
a fuel-rich "purge" cycle, rhodium catalyzes the reduction of
NO.sub.x (such as NO.sub.2) to N.sub.2 and H.sub.2O.
[0149] The micron-sized carrier particles, impregnated with the
composite reductive nanoparticles and nano-sized metal oxide, may
then be dried (for example, at about 30.degree. C. to about
95.degree. C., preferably about 60.degree. C. to about 70.degree.
C., at atmospheric pressure or at reduced pressure, such as from
about 1 pascal to about 90,000 pascal). After drying, the particles
may be calcined (at elevated temperatures, such as from 400.degree.
C. to about 700.degree. C., preferably about 500.degree. C. to
about 600.degree. C., more preferably at about 540.degree. C. to
about 560.degree. C., still more preferably at about 550.degree. C.
to about 560.degree. C., or at about 550.degree. C.; at atmospheric
pressure or at reduced pressure, for example, from about 1 pascal
to about 90,000 pascal, in ambient atmosphere or under an inert
atmosphere such as nitrogen or argon) to yield the composite
micro/nanoparticles, also referred to as nano-on-nano-on-micro
particles, or NNm.TM. particles. The drying step may be performed
before the calcining step to remove water prior to heating at the
higher calcining temperatures; this avoids boiling of the water,
which would disrupt the impregnated nanoparticles, which are lodged
in the pores of the micron-sized carrier.
[0150] The catalyst for reduction reactions can be made using a
procedure similar to that employed for production of the catalyst
for oxidation reactions. The nano-on-nano materials, for example
nano-sized Rh on nano-sized cerium oxide, can be prepared using the
method described above. In some instances, the sizes of the
nano-sized Rh are about 1 nm and the sizes of the nano-sized cerium
oxide are about 10 nm. In some instances, the sizes of the
nano-sized Rh are approximately 1 nm or less and the sizes of the
nano-sized cerium oxide are approximately 10 nm or less. In some
embodiments, the weight ratio of nano-sized Rh:nano-sized cerium
oxide is from 1%:99% to 20%:80%. In some embodiments, the weight
ratio of nano-sized Rh:nano-sized cerium oxide is from 2%:98% to
15%:85%. In some embodiments, the weight ratio of nano-sized
Rh:nano-sized cerium oxide is from 3%:97% to 10%:90%. In some
embodiments, the weight ratio of nano-sized Rh:nano-sized cerium
oxide is from 4%:96% to 6%:94%. In some embodiments, the weight
ratio of nano-sized Rh:nano-sized cerium oxide is about 5%:95%. In
any of the disclosed embodiments, the micron-sized cerium
oxide-containing material can comprise cerium oxide,
cerium-zirconium oxide, cerium-lanthanum oxide, cerium-yttrium
oxide, cerium-zirconium-lanthanum oxide, cerium-zirconium-yttrium
oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0.13La.sub.0.04O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide.
[0151] Next, calcination can be performed. The dried powder from
the previous step, that is, the nanomaterials on the micron-sized
material, can be baked at 550.degree. C. for two hours under
ambient air conditions. During the calcination step, the surfactant
is evaporated and the nanomaterials are glued or fixed onto the
surface of the micron-sized materials or the surface of the pores
of the micron-sized materials. At this stage, the material produced
(a catalytic active material) contains a micron-sized particle
(such as micron-sized cerium oxide or micron-sized cerium
oxide-containing material) having nano-on-nano (such as nano-sized
Rh on nano-sized cerium oxide) and nano-sized cerium oxide randomly
distributed on the surface.
[0152] The reductive NNm.TM. particles may contain from about 0.1%
to 1.0% rhodium by weight, or in another embodiment from about 0.2%
to 0.5% by weight, or in another embodiment, about 0.3% by weight,
or in another embodiment, about 0.4% by weight, of the total mass
of the NNm.TM. particle. The NNm.TM. particles can then be used for
formulations for coating substrates, where the coated substrates
may be used in catalytic converters.
[0153] Examples of production of NNm.TM. material are described in
the following co-owned patents and patent applications, the
disclosures of which are hereby incorporated by reference in their
entireties: U.S. Patent Publication No. 2005/0233380, U.S. Patent
Publication No. 2006/0096393, U.S. patent application Ser. No.
12/151,810, U.S. patent application Ser. No. 12/152,084, U.S.
patent application Ser. No. 12/151,809, U.S. Pat. No. 7,905,942,
U.S. patent application Ser. No. 12/152,111, U.S. Patent
Publication 2008/0280756, U.S. Patent Publication 2008/0277270,
U.S. patent application Ser. No. 12/001,643, U.S. patent
application Ser. No. 12/474,081, U.S. patent application Ser. No.
12/001,602, U.S. patent application Ser. No. 12/001,644, U.S.
patent application Ser. No. 12/962,518, U.S. patent application
Ser. No. 12/962,473, U.S. patent application Ser. No. 12/962,490,
U.S. patent appliaction Ser. No. 12/969,264, U.S. patent
application Ser. No. 12/962,508, U.S. patent application Ser. No.
12/965,745, U.S. patent application Ser. No. 12/969,503, and U.S.
patent application Ser. No. 13/033,514, WO 2011/081834
(PCT/US2010/59763) and US 2011/0143915 (U.S. patent application
Ser. No. 12/962,473).
Porous Materials for Use in "Nano-on-Nano-in-Micro" Particles
("NNiM" Particles)
[0154] Porous materials, production of porous materials,
micron-sized particles comprising composite nanoparticles and a
porous carrier ("Nano-on-Nano-in-Micro" particles or "NNiM"
particles), and production of micron-sized particles comprising
composite nanoparticles and a porous carrier
("Nano-on-Nano-in-Micro" particles or "NNiM" particles) are
described in the co-owned U.S. Provisional Patent Application No.
61/881,337 filed Sep. 23, 2013, U.S. patent application Ser. No.
14/494,156 filed Sep. 23, 2014, and International Patent Appl. No.
PCT/US2014/057036 filed Sep. 23, 2014, the disclosures of which are
hereby incorporated by reference in their entirety. In NNiM
material, particles, such as catalytic nanoparticles or catalytic
composite nanoparticles, are embedded within the porous carrier
which has been formed around the nanoparticles.
[0155] Generally, a preferred porous material comprises a material
that contains a large number of interconnected pores, holes,
channels, or pits, with an average pore, hole, channel, or pit
width (diameter) ranging from 1 nm to about 200 nm, or about 1 nm
to about 100 nm, or about 2 nm to about 50 nm, or about 3 nm to
about 25 nm. In some embodiments, the porous material has a mean
pore, hole, channel, or pit width (diameter) of less than about 1
nm, while in some embodiments, a porous carrier has a mean pore,
hole, channel, or pit width (diameter) of greater than about 100
nm. In some embodiments, the porous material has an average pore
surface area in a range of about 50 m.sup.2/g to about 500
m.sup.2/g. In some embodiments, the porous material has an average
pore surface area in a range of about 100 m.sup.2/g to about 400
m.sup.2/g. In some embodiments, a porous material has an average
pore surface area in a range of about 150 m.sup.2/g to about 300
m.sup.2/g. In some embodiments, the porous material has an average
pore surface area of less than about 50 m.sup.2/g. In some
embodiments, the porous material has an average pore surface area
of greater than about 200 m.sup.2/g. In some embodiments, the
porous material has an average pore surface area of greater than
about 300 m.sup.2/g. In some embodiments, a porous material has an
average pore surface area of about 200 m.sup.2/g. In some
embodiments, a porous material has an average pore surface area of
about 300 m.sup.2/g.
[0156] In some embodiments, the porous material may comprise porous
metal oxide, such as aluminum oxide or cerium oxide, or cerium
oxide, cerium-zirconium oxide, cerium-lanthanum oxide,
cerium-yttrium oxide, cerium-zirconium-lanthanum oxide,
cerium-zirconium-yttrium oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide, such as
Ce.sub.0.83Zr.sub.0.13La.sub.0.04O, a material that comprises about
86% cerium oxide, 10% zirconium oxide, and 4% lanthanum oxide,
Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O, or a material that
comprises about 40% cerium oxide, 50% zirconium oxide, 5% lanthanum
oxide, and 5% yttrium oxide. In some embodiments, a porous material
may comprise an organic polymer, such as polymerized resorcinol. In
some embodiments, the porous material may comprise amorphous
carbon. In some embodiments, the porous material may comprise
silica. In some embodiments, a porous material may be porous
ceramic. In some embodiments, the porous material may comprise a
mixture of two or more different types of interspersed porous
materials, for example, a mixture of aluminum oxide and polymerized
resorcinol. In some embodiments, the porous carrier may comprise
aluminum oxide after a spacer material has been removed. For
example, in some embodiments, a composite material may be formed
with interspersed aluminum oxide and polymerized resorcinol, and
the polymerized resorcinol is removed, for example, by calcination,
resulting in a porous carrier. In another embodiment, a composite
material may be formed with interspersed aluminum oxide and carbon
black, and the carbon black is removed, for example, by
calcination, resulting in a porous carrier.
[0157] In some embodiments, the porous material is a micron-sized
particle, with an average size between about 1 micron and about 100
microns, between about 1 micron and about 10 microns, between about
3 microns and about 7 microns, or between about 4 microns and about
6 microns. In other embodiments, the porous material may be
particles larger than about 7 microns. In some embodiments, the
porous material may not be in the form of particles, but a
continuous material.
[0158] The porous materials may allow gases and fluids to slowly
flow throughout the porous material via the interconnected
channels, being exposed to the high surface area of the porous
material. The porous materials can therefore serve as an excellent
carrier material for embedding particles in which high surface area
exposure is desirable, such as catalytic nanoparticles, as
described below.
Production of Porous Materials for Use in "Nano-on-Nano-in-Micro"
Particles ("NNiM" Particles)
[0159] A catalyst may be formed using a porous material. This
porous material includes, for example, catalyst particles embedded
within the porous structure of the material. In some embodiments,
the porous structure comprises alumina. Alumina porous structures
may be formed, for example, by the methods described in U.S. Pat.
No. 3,520,654, the disclosure of which is hereby incorporated by
reference in its entirety. In some embodiments, a sodium aluminate
solution, prepared by dissolving sodium oxide and aluminum oxide in
water, can be treated with sulfuric acid or aluminum sulfate to
reduce the pH to a range of about 4.5 to about 7. The decrease in
pH results in a precipitation of porous hydrous alumina which may
be spray dried, washed, and flash dried, resulting in a porous
alumina material. Optionally, the porous alumina material may be
stabilized with silica, as described in EP0105435 A2, the
disclosure of which is hereby incorporated by reference in its
entirety. A sodium aluminate solution can be added to an aluminum
sulfate solution, forming a mixture with a pH of about 8.0. An
alkaline metal silicate solution, such as a sodium silicate
solution, can be slowly added to the mixture, resulting in the
precipitation of a silica-stabilized porous alumina material. In
other embodiments, the porous structure comprises cerium oxide. In
other embodiments, the porous structure is a material that
comprises cerium oxide, cerium-zirconium oxide, cerium-lanthanum
oxide, cerium-yttrium oxide, cerium-zirconium-lanthanum oxide,
cerium-zirconium-yttrium oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide, such as
Ce.sub.083Zr.sub.o BLa.sub.004O, a material that comprises about
86% cerium oxide, 10% zirconium oxide, and 4% lanthanum oxide,
Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O, or a material that
comprises about 40% cerium oxide, 50% zirconium oxide, 5% lanthanum
oxide, and 5% yttrium oxide.
[0160] A porous material may also be generated by co-precipitating
aluminum oxide nanoparticles and amorphous carbon particles, such
as carbon black. Upon drying and calcination of the precipitate in
an ambient or oxygenated environment, the amorphous carbon is
exhausted. Simultaneously, the heat from the calcination process
causes the aluminum oxide nanoparticles to sinter together,
resulting in pores throughout the precipitated aluminum oxide where
the carbon black once appeared in the structure. In some
embodiments, aluminum oxide nanoparticles can be suspended in
ethanol, water, or a mix of ethanol and water. In some embodiments,
dispersant, such as DisperBYK.RTM.-145 from BYK (DisperBYK is a
registered trademark of BYK-Chemie GmbH LLC, Wesel, Germany for
chemicals for use as dispersing and wetting agents) may be added to
the aluminum oxide nanoparticle suspension. Carbon black with an
average grain size ranging from about 1 nm to about 200 nm, or
about 20 nm to about 100 nm, or about 20 nm to about 50 nm, or
about 35 nm, may be added to the aluminum oxide suspension. In some
embodiments, sufficient carbon black is added to obtain a pore
surface area of about 50 m.sup.2/g to about 500 m.sup.2/g should be
used, such as about 50 m.sup.2/g, about 100 m.sup.2/g, about 150
m.sup.2/g, about 200 m.sup.2/g, about 250 m.sup.2/g, about 300
m.sup.2/g, about 350 m.sup.2/g, about 400 m.sup.2/g, about 450
m.sup.2/g, or about 500 m.sup.2/g. The pH of the resulting mixture
can be adjusted to a range of about 2 to about 7, such as a pH of
between about 3 and about 5, preferably a pH of about 4, allowing
the particles to precipitate. In some embodiments, the precipitant
can be dried, for example by warming the precipitant (for example,
at about 30.degree. C. to about 95.degree. C., preferably about
60.degree. C. to about 70.degree. C., at atmospheric pressure or at
reduced pressure such as from about 1 pascal to about 90,000
pascal). Alternatively, in some embodiments, the precipitant may be
freeze-dried.
[0161] After drying, the material may then be calcined (at elevated
temperatures, such as from 400.degree. C. to about 700.degree. C.,
preferably about 500.degree. C. to about 600.degree. C., more
preferably at about 540.degree. C. to about 560.degree. C., still
more preferably at about 550.degree. C. to about 560.degree. C., or
at about 550.degree. C.; at atmospheric pressure or at reduced
pressure, for example, from about 1 pascal to about 90,000 pascal,
in ambient atmosphere). The calcination process causes the carbon
black to substantially burn away and the aluminum oxide
nanoparticles sinter together, yielding a porous aluminum oxide
material.
[0162] In some embodiments, a porous material may be made using the
sol-gel process. For example, an alumina porous material may be
formed by reacting aluminum chloride with propylene oxide.
Propylene oxide can be added to a solution of aluminum chloride
dissolved in a mixture of ethanol and water, which forms a porous
material that may be dried and calcined. In some embodiments,
epichlorodydrin may be used in place of propylene oxide. Other
methods of producing a porous material using the sol-gel method
known in the art may also be used, for example, a porous material
formed using the sol-gel process may be also be formed using
tetraethyl orthosilicate.
[0163] In some embodiments, the porous material may be formed by
mixing the precursors of a combustible gel with the precursors of a
metal oxide material prior to polymerization of the gel, allowing
the polymerization of the gel, drying the composite material, and
calcining the composite material, thereby exhausting the organic
gel components. In some embodiments, a gel activation solution
comprising a mixture of formaldehyde and propylene oxide can be
mixed with a gel monomer solution comprising a mixture of aluminum
chloride and resorcinol. Upon mixing of the gel activation solution
and the gel monomer solution, a combustible organic gel component
forms as a result of the mixing of formaldehyde and resorcinol, and
a non-combustible inorganic metal oxide material forms as a result
of mixing the propylene oxide and aluminum chloride. The resulting
composite material can be calcined, causing the combustible organic
gel component to burn away, resulting in a porous metal oxide
material.
[0164] In some embodiments, the gel activation solution may be
prepared by mixing aqueous formaldehyde and propylene oxide. The
formaldehyde is preferably in an aqueous solution. In some
embodiments, the concentration of the aqueous formaldehyde solution
is about 5 wt % to about 50 wt % formaldehyde, about 20 wt % to
about 40 wt % formaldehyde, or about 30 wt % to about 40 wt %
formaldehyde. Preferably, the aqueous formaldehyde is about 37 wt %
formaldehyde. In some embodiments, the aqueous formaldehyde may
contain about 5 wt % to about 15 wt % methanol to stabilize the
formaldehyde in solution. The aqueous formaldehyde can be added in
a range of about 25% to about 50% of the final weight of the gel
activation solution, with the remainder being propylene oxide.
Preferably, the gel activation solution comprises 37.5 wt % of the
aqueous formaldehyde solution (which itself comprises 37 wt %
formaldehyde) and 62.5 wt % propylene oxide, resulting in a final
formaldehyde concentration of about 14 wt % of the final gel
activation solution.
[0165] Separately from the gel activation solution, a gel monomer
solution may be produced by dissolving aluminum chloride in a
mixture of resorcinol and ethanol. Resorcinol can be added at a
range of about 2 wt % to about 10 wt %, with about 5 wt % being a
typical value. Aluminum chloride can be added at a range of about
0.8 wt % to about 5 wt %, with about 1.6 wt % being a typical
value.
[0166] The gel activation solution and gel monomer solution can be
mixed together at a ratio at about 1:1 in terms of (weight of gel
activation solution):(weight of gel monomer solution). The final
mixture may then be dried (for example, at about 30.degree. C. to
about 95.degree. C., preferably about 50.degree. C. to about
60.degree. C., at atmospheric pressure or at reduced pressure such
as from about 1 pascal to about 90,000 pascal, for about one day to
about 5 days, or for about 2 days to about 3 days). After drying,
the material may then be calcined (at elevated temperatures, such
as from 400.degree. C. to about 700.degree. C., preferably about
500.degree. C. to about 600.degree. C., more preferably at about
540.degree. C. to about 560.degree. C., still more preferably at
about 550.degree. C. to about 560.degree. C., or at about
550.degree. C.; at atmospheric pressure or at reduced pressure, for
example, from about 1 pascal to about 90,000 pascal, in ambient
atmosphere, for about 12 hours to about 2 days, or about 16 hours
to about 24 hours) to burn off the combustible organic gel
component and yield a porous aluminum oxide carrier.
Micron-Sized Particles Comprising Composite Nanoparticles and a
Porous Carrier ("Nano-on-Nano-in-Micro" Particles or "NNiM"
Particles)
[0167] Nanoparticles or composite nanoparticles produced by plasma
production or other methods may be embedded within a porous
material to enhance the surface area of catalytic components. The
porous material may then serve as a carrier for the composite
nanoparticles, allowing gases and fluids to slowly flow throughout
the porous material via the interconnected channels. The high
porosity of the carrier results in a high surface area within the
carrier allowing increased contact of the gases and fluids with the
embedded catalytic components, such as composite nanoparticles.
Embedding the composite nanoparticles within the porous carrier
results in a distinct advantage over those technologies where
catalytically active nanoparticles are positioned on the surface of
carrier micro-particles or do not penetrate as effectively into the
pores of the support. When catalytically active nanoparticles are
position on the surface of carrier micro-particles, some
catalytically active nanoparticles can become buried by other
catalytically active nanoparticles, causing them to be inaccessible
to target gases because of the limited exposed surface area. When
the composite nanoparticles are embedded within the porous carrier,
however, gases can flow through the pores of the carrier to
catalytically active components.
[0168] The porous carrier may contain any large number of
interconnected pores, holes, channels, or pits, preferably with an
average pore, hole, channel, or pit width (diameter) ranging from 1
nm to about 200 nm, or about 1 nm to about 100 nm, or about 2 nm to
about 50 nm, or about 3 nm to about 25 nm. In some embodiments, the
porous carrier has a mean pore, hole, channel, or pit width
(diameter) of less than about 1 nm, while in some embodiments, a
porous carrier has a mean pore, hole, channel, or pit width
(diameter) of greater than about 100 nm. In some embodiments, a
porous material has an average pore surface area in a range of
about 50 m.sup.2/g to about 500 m.sup.2/g. In some embodiments, a
porous material has an average pore surface area in a range of
about 100 m.sup.2/g to about 400 m.sup.2/g. In some embodiments, a
porous material has an average pore surface area in a range of
about 150 m.sup.2/g to about 300 m.sup.2/g. In some embodiments, a
porous material has an average pore surface area of less than about
50 m.sup.2/g. In some embodiments, a porous material has an average
pore surface area of greater than about 200 m.sup.2/g. In some
embodiments, a porous material has an average pore surface area of
greater than about 300 m.sup.2/g. In some embodiments, a porous
material has an average pore surface area of about 200 m.sup.2/g.
In some embodiments, a porous material has an average pore surface
area of about 300 m.sup.2/g.
[0169] A porous carrier embedded with nanoparticles can be formed
with any porous material. A porous carrier may include, but is not
limited to, any gel produced by the sol-gel method, for example,
alumina (Al.sub.2O.sub.3), cerium oxide, or silica aerogels as
described herein. In some embodiments, the porous carrier may
comprise a porous metal oxide, such as aluminum oxide. In some
embodiments, a porous carrier may comprise an organic polymer, such
as polymerized resorcinol. In some embodiments, the porous carrier
may comprise amorphous carbon. In some embodiments, the porous
carrier may comprise silica. In some embodiments, a porous carrier
may be porous ceramic. In some embodiments, the porous carrier may
comprise a mixture of two or more different types of interspersed
porous materials, for example, a mixture of aluminum oxide and
polymerized resorcinol.
[0170] In some embodiments, a carrier may comprise a combustible
component, for example amorphous carbon or a polymerized organic
gel such as polymerized resorcinol, and a non-combustible
component, for example a metal oxide such as aluminum oxide. A
catalytic material can include composite nanoparticles embedded in
a carrier comprising a combustible component and a non-combustible
component.
[0171] Catalytic particles, such as the catalytic nanoparticles or
catalytic composite nanoparticles described herein, are embedded
within the porous carrier. This can be accomplished by including
the catalytic particles in the mixture used to form the porous
carrier. In some embodiments, the catalytic particles are evenly
distributed throughout the porous carrier. In other embodiments,
the catalytic particles are clustered throughout the porous
carrier. In some embodiments, platinum group metals comprise about
0.001 wt % to about10 wt % of the total catalytic material
(catalytic particles and porous carrier). For example, platinum
group metals may comprise about 1 wt % to about 8 wt % of the total
catalytic material (catalytic particles and porous carrier). In
some embodiments, platinum group metals may comprise less than
about 10 wt %, less than about 8 wt %, less than about 6 wt %, less
than about 4 wt %, less than about 2 wt %, or less than about 1 wt
% of the total catalytic material (catalytic particles and porous
carrier). In some embodiments, platinum group metals may comprise
about 1 wt %, about 2 wt %, about 3 wt %, about 4 wt %, about 5 wt
%, about 6 wt %, about 7 wt %, about 8 wt %, about 9 wt %, or about
10 wt % of the total catalytic material (catalytic particles and
porous carrier).
[0172] In some embodiments, the catalytic nanoparticles comprise
one or more platinum group metals. In embodiments with two or more
platinum group metals, the metals may be in any ratio. In some
embodiments, the catalytic nanoparticles comprise platinum group
metal or metals, such as Pt:Pd in about a 5:1 ratio to about 100:1
ratio by weight, or about 6:1 to about 75:1 ratio by weight, or
about 7:1 to about 50:1 ratio by weight, or about 8:1 to about 25:1
ratio by weight, or about 9:1 to about 15:1 ratio by weight. In one
embodiment, the catalytic nanoparticles comprise platinum group
metal or metals, such as Pt:Pd in about 10:1 ratio by weight.
[0173] The composite nanoparticles (nano-on-nano particles)
embedded within a porous carrier may take the form of a powder to
produce composite catalytic micro-particles, referred to as
"nano-on-nano-in-micron" particles or "NNiM" particles. The
micron-sized NNiM particles can have an average size between about
1 micron and about 100 microns, such as between about 1 micron and
about 10 microns, between about 3 microns and about 7 microns, or
between about 4 microns and about 6 microns. The NNiM particles may
comprise about 0.001 wt % to about10 wt % of the total mass of the
NNiM particle (catalytic particles and porous carrier). For
example, platinum group metals may comprise about 1 wt % to about 8
wt % of the total mass of the NNiM particle (catalytic particles
and porous carrier). In some embodiments, platinum group metals may
comprise less than about 10 wt %, less than about 8 wt %, less than
about 6 wt %, less than about 4 wt %, less than about 2 wt %, or
less than about 1 wt % of the total mass of the NNiM particle
(catalytic particles and porous carrier). In some embodiments,
platinum group metals may comprise about 1 wt %, about 2 wt %,
about 3 wt %, about 4 wt %, about 5 wt %, about 6 wt %, about 7 wt
%, about 8 wt %, about 9 wt %, or about 10 wt % of the total mass
of the NNiM particle (catalytic particles and porous carrier).
[0174] NNiM particles may be used for any catalytic purpose. For
example, NNiM particles may be suspended in a liquid, for example
ethanol or water, which may catalyze dissolved compounds.
Alternatively, the NNiM particles may be used as a solid state
catalyst. For example, the NNiM particles can then be used in
catalytic converters.
Production of Micron-sized Particles Comprising Composite
Nanoparticles and a Porous Carrier ("Nano-on-Nano-in-Micro"
Particles or "NNiM" Particles)
[0175] In some embodiments, catalytic nanoparticles or composite
nanoparticles can be embedded in a porous carrier by forming a
suspension or colloid of nanoparticles, and mixing the suspension
or colloid of nanoparticles with a porous material precursor
solution. Upon solidification of the porous material with the
mixture, such as by polymerization, precipitation, or
freeze-drying, the porous material will form around the
nanoparticles, resulting in a catalytic material comprising
nanoparticles embedded in a porous carrier. In some embodiments,
the catalytic material is then processed, such as by grinding or
milling, into a micron-sized powder, resulting in NNiM
particles.
[0176] Described below is the production of NNiM particles using a
porous aluminum oxide carrier formed using a composite carrier
comprising a combustible organic gel component and an aluminum
oxide component, followed by drying and calcination. However, one
skilled in the art would understand any manner of porous carrier
originating from soluble precursors may be used to produce
catalytic material comprising composite nanoparticles embedded
within a porous carrier using the methods described herein.
[0177] For typical NNiM particles produced using a porous aluminum
oxide carrier formed using a composite carrier comprising a
combustible organic gel component and an aluminum oxide component,
the composite nanoparticles are initially dispersed in ethanol. In
some embodiments, at least 95 vol % ethanol is used. In some
embodiments, at least 99 vol % ethanol is used. In some
embodiments, at least 99.9 vol % ethanol is used. Dispersants
and/or surfactants are typically added to the ethanol before
suspension of the composite nanoparticles. A suitable surfactant
includes DisperBYK.RTM.-145 from BYK-Chemie GmbH LLC, Wesel, which
can be added in a range of about 2 wt % to about 12 wt %, with
about 7 wt % being a typical value, and dodecylamine, which can be
added in a range of about 0.25 wt % to about 3 wt %, with about 1
wt % being a typical value. Preferably, both DisperBYK.RTM.-145 and
dodecylamine are used at about 7 wt % and 1 wt %, respectively. In
some embodiments, the mixture of ethanol, composite nanoparticles,
and surfactants and/or dispersants is sonicated to uniformly
disperse the composite nanoparticles. The quantity of composite
nanoparticles particles in the dispersion may be in the range of
about 5 wt % to about 20 wt %.
[0178] Separately from the composite nanoparticle suspension, a gel
activation solution is prepared by mixing formaldehyde and
propylene oxide. The formaldehyde is preferably in an aqueous
solution. In some embodiments, the concentration of the aqueous
formaldehyde solution is about 5 wt % to about 50 wt %
formaldehyde, about 20 wt % to about 40 wt % formaldehyde, or about
30 wt % to about 40 wt % formaldehyde. Preferably, the aqueous
formaldehyde is about 37 wt % formaldehyde. In some embodiments,
the aqueous formaldehyde may contain about 5 wt % to about 15 wt %
methanol to stabilize the formaldehyde in solution. The aqueous
formaldehyde solution can be added in a range of about 25% to about
50% of the final weight of the gel activation solution, with the
remainder being propylene oxide. Preferably, the gel activation
solution comprises 37.5 wt % of the aqueous formaldehyde solution
(which itself comprises 37 wt % formaldehyde) and 62.5 wt %
propylene oxide, resulting in a final formaldehyde concentration of
about 14 wt % of the final gel activation solution.
[0179] Separately from the composite nanoparticle suspension and
gel activation solution, an aluminum chloride solution is produced
by dissolving aluminum chloride in a mixture of resorcinol and
ethanol. Resorcinol can be added at a range of about 10 wt % to
about 30 wt %, with about 23 wt % being a typical value. Aluminum
chloride can be added at a range of about 2 wt % to about 12 wt %,
with about 7 wt % being a typical value.
[0180] The composite nanoparticle suspension, gel activation
solution, and aluminum chloride solution can be mixed together at a
ratio from of about 100:10:10 to about 100:40:40, or about
100:20:20 to about 100:30:30, or about 100:25:25, in terms of
(weight of composite nanoparticle suspension):(weight of gel
activation solution):(weight of aluminum chloride solution). The
final mixture will begin to polymerize into a carrier embedded with
composite nanoparticles. The carrier comprises a combustible
component, an organic gel, and a non-combustible component,
aluminum oxide. The resulting carrier may then be dried (for
example, at about 30.degree. C. to about 95.degree. C., preferably
about 50.degree. C. to about 60.degree. C., at atmospheric pressure
or at reduced pressure such as from about 1 pascal to about 90,000
pascal, for about one day to about 5 days, or for about 2 days to
about 3 days). After drying, the resulting carrier may then be
calcined (at elevated temperatures, such as from 400.degree. C. to
about 700.degree. C., preferably about 500.degree. C. to about
600.degree. C., more preferably at about 540.degree. C. to about
560.degree. C., still more preferably at about 550.degree. C. to
about 560.degree. C., or at about 550.degree. C.; at atmospheric
pressure or at reduced pressure, for example, from about 1 pascal
to about 90,000 pascal, in ambient atmosphere or under an inert
atmosphere such as nitrogen or argon), to yield a porous carrier
comprising composite catalytic nanoparticles and aluminate. When
the composite carrier is calcined under ambient atmosphere or other
oxygenated conditions, organic material, such as polymerized
resorcinol, formaldehyde, or propylene oxide, is burnt off,
resulting in a substantially pure aluminum oxide porous carrier
embedded with composite nanoparticles. If the composite carrier is
calcined under an inert atmosphere, such as argon or nitrogen, the
organic materials may become substantially porous amorphous carbon
interspersed with the porous aluminum oxide embedded with composite
nanoparticles. The resulting porous carrier can be processed, such
as by grinding or milling, into a micro-sized powder of NNiM
particles.
[0181] In another embodiment, a composite catalytic nanoparticles
may be mixed with a dispersion comprising metal oxide
nanoparticles, such as aluminum oxide nanoparticles, and amorphous
carbon, such as carbon black. The dispersed solid particles from
resulting dispersed colloid may be separated from the liquid by
co-precipitation, dried, and calcined. Upon calcination of the
solid material in an ambient or oxygenated environment, the
amorphous carbon is exhausted. Simultaneously, the heat from the
calcination process causes the aluminum oxide nanoparticles to
sinter together, resulting in pores throughout the precipitated
aluminum oxide.
[0182] In some embodiments, aluminum oxide nanoparticles can be
suspended in ethanol, water, or a mix of ethanol and water. Carbon
black with an average grain size ranging from about 1 nm to about
200 nm, or about 20 nm to about 100 nm, or about 20 nm to about 50
nm, or about 35 nm, may be added to the aluminum oxide suspension.
In some embodiments, sufficient carbon black to obtain a pore
surface area of about 50 m.sup.2/g to about 500 m.sup.2/g should be
used, such as about 50 m.sup.2/g, about 100 m.sup.2/g, about 150
m.sup.2/g, about 200 m.sup.2/g, about 250 m.sup.2/g, about 300
m.sup.2/g, about 350 m.sup.2/g, about 400 m.sup.2/g, about 450
m.sup.2/g, or about 500 m.sup.2/g. Composite nanoparticles may be
mixed into the dispersion comprising aluminum oxide nanoparticles
and carbon black. In some embodiments, the composite nanoparticles
are dispersed in a separate colloid, optionally with dispersants or
surfactants, before being mixed with the dispersion comprising
aluminum oxide nanoparticles and carbon black. The pH of the
resulting mixture can be adjusted to a range of about 2 to about 7,
such as a pH of between about 3 and about 5, preferably a pH of
about 4, allowing the particles to precipitate. The precipitant can
be dried (for example, at about 30.degree. C. to about 95.degree.
C., preferably about 50.degree. C. to about 70.degree. C., at
atmospheric pressure or at reduced pressure such as from about 1
pascal to about 90,000 pascal, for about one day to about 5 days,
or for about 2 days to about 3 days). After drying, the carrier may
then be calcined (at elevated temperatures, such as from
400.degree. C. to about 700.degree. C., preferably about
500.degree. C. to about 600.degree. C., more preferably at about
540.degree. C. to about 560.degree. C., still more preferably at
about 550.degree. C. to about 560.degree. C., or at about
550.degree. C.; at atmospheric pressure or at reduced pressure, for
example, from about 1 pascal to about 90,000 pascal, in ambient
atmosphere). The calcination process causes the carbon black to
substantially burn away and the aluminum oxide nanoparticles sinter
together, yielding a porous aluminum oxide carrier embedded with
composite nanoparticles.
[0183] The resulting carrier may be further processed, for example
by grinding or milling, into micron-sized NNiM particles.
NNm.TM. and NNiM Particles with Inhibited Migration of Platinum
Group Metals
[0184] The oxidative NNm.TM. particles including an aluminum oxide
micron-sized carrier particle bearing composite nanoparticles,
where the composite nanoparticles are produced under reducing
conditions, are particularly advantageous for use in catalytic
converter applications. The NNiM particles, including those made
using an aluminum oxide porous carrier and composite nanoparticles,
where the carrier is produced by methods described herein and
composite nanoparticles produced under reducing conditions, are
also particularly advantageous for use in catalytic converter
applications. The platinum group metal of the catalytic
nanoparticle has a greater affinity for the partially reduced
Al.sub.2O.sub.(3-x) surface of the support nanoparticle than for
the Al.sub.2O.sub.3 surface of the micron-sized carrier particles.
Thus, at elevated temperatures, neighboring PGM nanoparticles bound
to neighboring Al.sub.2O.sub.(3-x) support nano-particles are less
likely to migrate on the Al.sub.2O.sub.3 micron-sized carrier
particle surface and agglomerate into larger catalyst clumps. Since
the larger agglomerations of catalyst have less surface area and
are less effective as catalysts, the inhibition of migration and
agglomeration provides a significant advantage for the NNm.TM. and
NNiM particles. In contrast, palladium and platinum particles
deposited by wet-chemical precipitation onto alumina support
demonstrate higher mobility and migration, forming agglomerations
of catalyst and leading to decreased catalytic efficacy over time
(that is, catalyst aging).
Barium-Oxide Nanoparticles and Micron Particles
[0185] Barium oxide nanoparticles may be combined with porous
micron supports as described below, and may be included in the
oxidative washcoat layer, the reductive washcoat layer, the
NO.sub.x storage layer, or any combination of the oxidative,
reductive, and NO.sub.x storage washcoat layers. As an alternative
embodiment, micron-sized barium oxide particles may be included in
the oxidative washcoat layer, or any combination of the oxidative,
reductive, and NO.sub.x storage washcoat layers. In another
alternative embodiment, both barium oxide nanoparticles and barium
oxide micron particles may be included in the oxidative washcoat
layer, the reductive washcoat layer, or any combination of the
oxidative, reductive, and NO.sub.x storage washcoat layers. When
the NO.sub.x storage particles and reductive particles are in the
same layer, barium oxide nanoparticles and/or barium oxide micron
particles may be included in this combination layer.
[0186] The barium oxide is an absorber that binds and holds
NO.sub.x compounds, particularly NO.sub.2, as well as sulfur
compounds such SO.sub.x, particularly SO.sub.2, during lean burn
times of engine operation. These gases are then released and
reduced by the catalysts during a period of rich engine operation.
When used alone or in combination with other NO.sub.x trapping
materials, such as those described herein, the amount of PGM needed
to store NO.sub.x gases can be substantially reduced or
eliminated.
[0187] Barium oxide nanoparticles and barium oxide micron particles
may be produced by the plasma-based methods described above with
respect to the oxidative and reductive nano-on-nano particles. The
barium oxide feed material can be fed into the into a plasma gun,
where the material is vaporized.
[0188] In some embodiments, the barium oxide nanoparticles have an
average diameter of approximately 20 nm or less, or approximately
15 nm or less, or between approximately 10 nm and approximately 20
nm, that is, approximately 15 nm.+-.5 nm, or between approximately
10 nm and approximately 15 nm, that is, approximately 12.5
nm.+-.2.5 nm. In some embodiments, the barium oxide nanoparticles
have a diameter of approximately 20 nm or less, or approximately 15
nm or less, or between approximately 10 nm and approximately 20 nm,
that is, approximately 15 nm.+-.5 nm, or between approximately 10
nm and approximately 15 nm, that is, approximately 12.5 nm.+-.2.5
nm.
[0189] In some embodiments, the barium oxide micron particles have
an average diameter of approximately 10 .mu.m or less, or
approximately 8 .mu.m or less, or approximately 5 .mu.m or less, or
approximately 2 .mu.m or less, or approximately 1.5 .mu.m or less,
or approximately 1 .mu.m or less, or approximately 0.5 .mu.m or
less. In some embodiments, the barium oxide micron particles have
an average diameter between approximately 6 .mu.m and approximately
10 .mu.m, that is, approximately 8 .mu.m.+-.2 .mu.m, or between
approximately 7 .mu.m and approximately 9 .mu.m, that is,
approximately 8 .mu.m.+-.1 .mu.m. In some embodiments, the barium
oxide micron particles have an average diameter between
approximately 0.5 .mu.m and approximately 2 .mu.m, that is,
approximately 1.25 .mu.m.+-.0.75 m, or between approximately 1.0
.mu.m and approximately 1.5 .mu.m, that is, approximately 1.25
.mu.m.+-.0.25 m.
[0190] The barium oxide nanoparticles may be impregnated into
micron-sized alumina supports. The procedure for impregnating these
supports may be similar to the process described above with respect
to impregnating the oxidative composite nanoparticles into
micron-sized aluminum oxide supports. Preferably, the barium oxide
nanoparticles are prepared by applying a dispersion of barium oxide
nanoparticles to porous, micron-sized aluminum oxide, as described
with respect to the oxidative nanoparticles. The porous,
micron-sized aluminum oxide powders may be stabilized with a small
percentage of lanthanum (about 2% to about 4% La). One commercial
alumina powder suitable for use is MI-386.
[0191] Exemplary ranges for the nano-sized BaO-alumina ratio
include 1-20% BaO to 80% to 99% aluminum oxide micron support;
2-15% BaO to 85% to 98% aluminum oxide micron support; 5%-12% BaO
to 88% to 95% aluminum oxide micron support; and about 10% BaO to
about 90% aluminum oxide micron support, expressed as weight
percentages. In one embodiment, the nano-BaO-impregnated aluminum
oxide comprises 10%, or about 10%, nano-BaO by weight and 90%, or
about 90%, aluminum oxide by weight.
[0192] The barium oxide nanoparticles may be impregnated into
micron-sized cerium oxide supports or micron-sized cerium
oxide-containing material supports. The procedure for impregnating
these supports may be similar to the process described above with
respect to impregnating the reductive composite nanoparticles into
micron-sized cerium oxide supports or micron-sized cerium
oxide-containing material supports. Preferably, the barium oxide
nanoparticles are prepared by applying a dispersion of barium oxide
nanoparticles to porous, micron-sized cerium oxide or micron-sized
cerium oxide-containing material, as described with respect to the
reductive nanoparticles. The micron-sized cerium oxide may contain
zirconium oxide. In some embodiments, the micron-sized cerium oxide
is substantially free of zirconium oxide. In some embodiments, the
micron-sized cerium oxide-containing material comprises cerium
oxide, cerium-zirconium oxide, cerium-lanthanum oxide,
cerium-yttrium oxide, cerium-zirconium-lanthanum oxide,
cerium-zirconium-yttrium oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0.13La.sub.0.04O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide. One commercial cerium oxide powder suitable for use is
HSA5.
[0193] Exemplary ranges for the nano-sized BaO-cerium oxide ratio
include 1-20% BaO to 80% to 99% cerium oxide micron support (or
cerium oxide-containing material micron support); 2-15% BaO to 85%
to 98% cerium oxide micron support(or cerium oxide-containing
material micron support); 5%-12% BaO to 88% to 95% cerium oxide
micron support(or cerium oxide-containing material micron support);
and about 10% BaO to about 90% cerium oxide micron support(or
cerium oxide-containing material micron support), expressed as
weight percentages. In one embodiment, the nano-BaO-impregnated
cerium oxide comprises 8%, or about 8%, nano-BaO by weight and 92%,
or about 92%, cerium oxide by weight. These ratios can be also be
used with other support materials containing cerium oxide, such as
cerium-zirconium oxide, cerium-lanthanum oxide, cerium-yttrium
oxide, cerium-zirconium-lanthanum oxide, cerium-zirconium-yttrium
oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide.
[0194] In some embodiments, the cerium oxide support (or support
comprising cerium oxide and other materials, such as
cerium-zirconium oxide, cerium-lanthanum oxide, cerium-yttrium
oxide, cerium-zirconium-lanthanum oxide, cerium-zirconium-yttrium
oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide) is impregnated with
barium oxide using wet chemistry techniques.
[0195] Barium oxide micron particles are used simply by adding them
to the washcoat when desired, in the amount desired, along with the
other solid ingredients.
NO.sub.x Trapping Particles
[0196] NO.sub.x trapping particles are also referred to herein as
NO.sub.x trapping materials, NO.sub.x storage particles, or
NO.sub.x storage materials. An NO.sub.x trapping particle is a
particle that holds NO.sub.x gases during lean-burn engine
operation and releases the gases when the oxygen content in the
exhaust gas is reduced. NO.sub.x trapping particles can be a single
type of particle or multiple types of particles.
[0197] NO.sub.x trapping particles comprise micron-sized cerium
oxide particles or micron-sized cerium oxide-containing material
particles. Suitable micron-sized cerium oxide particles or
micron-sized cerium oxide-containing material particles include,
but are not limited to, HSA5. In some embodiments, the micron-sized
cerium oxide particles or micron-sized cerium oxide-containing
material particles may include platinum, palladium, or a mixture
thereof. In some embodiments, the micron-sized cerium oxide
particles or micron-sized cerium oxide-containing material
particles may include barium oxide. In some embodiments, the
micron-sized cerium oxide particles or micron-sized cerium
oxide-containing material particles may include barium oxide in
addition to platinum, palladium, or a mixture thereof. The
micron-sized cerium oxide may contain zirconium oxide. In some
embodiments, the micron-sized cerium oxide is substantially free of
zirconium oxide. In some embodiments, the micron-sized cerium
oxide-containing material comprises cerium oxide, cerium-zirconium
oxide, cerium-lanthanum oxide, cerium-yttrium oxide,
cerium-zirconium-lanthanum oxide, cerium-zirconium-yttrium oxide,
cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0.13La.sub.0.04O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide.
[0198] The barium oxide is an absorber that binds and holds
NO.sub.x compounds during lean burn times of engine operation.
These gases are then released and reduced by the catalysts during a
period of rich engine operation. During lean burn times of engine
operation, barium oxide particles promote the dimerization of
NO.sub.x gases to yield N.sub.2O.sub.4 and barium nitrate.
Subsequently, during fuel rich burn times of engine operation, the
barium nitrate and the N.sub.2O.sub.4 dimer are converted to barium
oxide and NO.sub.2, respectively. In this way, the released
NO.sub.2 can then be reduced to the benign gases N.sub.2 and
H.sub.2O.
NO.sub.x Trapping Particles: Use of Wet Chemistry Techniques
[0199] In some embodiments, the NO.sub.x trapping particles
comprising micron-sized cerium oxide particles or micron-sized
cerium oxide-containing material particles may be prepared using
wet chemistry techniques. In some embodiments, the NO.sub.x
trapping particles can be a single type of particle. In some
embodiments, the micron-sized cerium oxide particles or
micron-sized cerium oxide-containing material particles contain
platinum, palladium, or a mixture thereof. In some embodiments,
platinum is used alone. In other embodiments, palladium is used
alone. In further embodiments, platinum may be used in combination
with palladium. For example, the micron-sized cerium oxide
particles or micron-sized cerium oxide-containing material
particles may contain a mixture of 5:1 to 100:1 platinum to
palladium. In some embodiments, the micron-sized cerium oxide
particles or micron-sized cerium oxide-containing material
particles may contain a mixture of 6:1 to 75:1 platinum to
palladium. In some embodiments, the micron-sized cerium oxide
particles or micron-sized cerium oxide-containing material
particles may contain a mixture of 7:1 to 50:1 platinum to
palladium. In some embodiments, the micron-sized cerium oxide
particles or micron-sized cerium oxide-containing material
particles may contain a mixture of 8:1 to 25:1 platinum to
palladium. In some embodiments, the micron-sized cerium oxide
particles or micron-sized cerium oxide-containing material
particles may contain a mixture of 9:1 to 15:1 platinum to
palladium. In some embodiments, the micron-sized cerium oxide
particles or micron-sized cerium oxide-containing material
particles may contain a mixture of 10:1 platinum to palladium, or
approximately 10:1 platinum to palladium. The platinum, palladium,
or mixture thereof may be added to the micron-sized cerium oxide
particles or micron-sized cerium oxide-containing material
particles using wet chemistry techniques. The platinum, palladium,
or mixture thereof may be added to the micron-sized cerium oxide
particles or micron-sized cerium oxide-containing material
particles using nitrate and/or chloride salts of platinum and/or
palladium such as Pt(NO.sub.3).sub.4, Pd(NO.sub.3).sub.4,
H.sub.2PtCl.sub.6, and H.sub.2PdCl.sub.6. In some embodiments, the
micron-sized cerium oxide-containing material comprises cerium
oxide, cerium-zirconium oxide, cerium-lanthanum oxide,
cerium-yttrium oxide, cerium-zirconium-lanthanum oxide,
cerium-zirconium-yttrium oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0.13La.sub.0.04O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.006O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide.
[0200] In some embodiments, the micron-sized cerium oxide particles
or micron-sized cerium oxide-containing material particles may
contain barium oxide particles, which are discussed above. The
barium oxide particles may be added to the micron-sized cerium
oxide particles or micron-sized cerium oxide-containing material
particles using wet chemistry techniques. The barium oxide
particles may be added to the micron-sized cerium oxide particles
or micron-sized cerium oxide-containing material particles using
barium acetate. In some embodiments, the micron-sized cerium oxide
particles or micron-sized cerium oxide-containing material
particles may contain 5-15% barium oxide particles. In some
embodiments, the micron-sized cerium oxide particles or
micron-sized cerium oxide-containing material particles may contain
6-12% barium oxide particles. In some embodiments, the micron-sized
cerium oxide particles or micron-sized cerium oxide-containing
material particles may contain 7-9% barium oxide particles. In some
embodiments, the micron-sized cerium oxide particles or
micron-sized cerium oxide-containing material particles may contain
about 8% barium oxide particles. The micron-sized cerium oxide may
contain zirconium oxide. In some embodiments, the micron-sized
cerium oxide is substantially free of zirconium oxide. In some
embodiments, the micron-sized cerium oxide-containing material
comprises cerium oxide, cerium-zirconium oxide, cerium-lanthanum
oxide, cerium-yttrium oxide, cerium-zirconium-lanthanum oxide,
cerium-zirconium-yttrium oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0.13La.sub.0.04O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide.
[0201] In some embodiments, the micron-sized cerium oxide particles
or micron-sized cerium oxide-containing material particles may
contain barium oxide particles and platinum. In other embodiments,
the micron-sized cerium oxide particles or micron-sized cerium
oxide-containing material particles may contain barium oxide
particles and palladium. In some embodiments, the micron-sized
cerium oxide particles or micron-sized cerium oxide-containing
material particles may contain barium oxide particles and a mixture
of platinum and palladium. For example, the micron-sized cerium
oxide particles or micron-sized cerium oxide-containing material
particles may contain barium oxide particles and a mixture of 5:1
to 100:1 platinum to palladium. In some embodiments, the
micron-sized cerium oxide particles or micron-sized cerium
oxide-containing material particles may contain barium oxide
particles and a mixture of 6:1 to 75:1 platinum to palladium. In
some embodiments, the micron-sized cerium oxide particles or
micron-sized cerium oxide-containing material particles may contain
barium oxide particles and a mixture of 7:1 to 50:1 platinum to
palladium. In some embodiments, the micron-sized cerium oxide
particles or micron-sized cerium oxide-containing material
particles may contain barium oxide particles and a mixture of 8:1
to 25:1 platinum to palladium. In some embodiments, the
micron-sized cerium oxide particles or micron-sized cerium
oxide-containing material particles may contain barium oxide
particles and a mixture of 9:1 to 15:1 platinum to palladium. In
some embodiments, the micron-sized cerium oxide particles or
micron-sized cerium oxide-containing material particles may contain
barium oxide particles and a mixture of 10:1 platinum to palladium,
or approximately 10:1 platinum to palladium. In a preferred
embodiment, the micron-sized cerium oxide particles or micron-sized
cerium oxide-containing material particles contain about 8% barium
oxide and a mixture of about 10:1 platinum to palladium. The barium
oxide particles and platinum, palladium, or mixture thereof may be
added to the micron-sized cerium oxide particles or micron-sized
cerium oxide-containing material particles using wet chemistry
techniques. In some embodiments, the barium oxide particles and the
platinum, palladium, or mixture thereof are on the same
micron-sized cerium oxide particle or micron-sized cerium
oxide-containing material particle. In other embodiments, the
barium oxide particles and the platinum, palladium, or mixture
thereof are on different micron-sized cerium oxide particles or
micron-sized cerium oxide-containing material particles. The
micron-sized cerium oxide may contain zirconium oxide. In some
embodiments, the micron-sized cerium oxide is substantially free of
zirconium oxide. In some embodiments, the micron-sized cerium
oxide-containing material comprises cerium oxide, cerium-zirconium
oxide, cerium-lanthanum oxide, cerium-yttrium oxide,
cerium-zirconium-lanthanum oxide, cerium-zirconium-yttrium oxide,
cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0.13La.sub.0.04O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide.
NO.sub.x Trapping Particles: "Nano-on-Nano-on-Micro" Particles
("NNm.TM. " Particles)
[0202] In some embodiments, the NO.sub.x trapping particles include
different types of particles. In some embodiments, the NO.sub.x
trapping particles comprise a first particle and a second particle.
In some embodiments, the first particle is comprised of
micron-sized cerium oxide or micron-sized cerium oxide-containing
material. In some embodiments, the micron-sized cerium oxide
particles or micron-sized cerium oxide-containing material
particles may contain barium oxide particles. The barium oxide
particles may be added to the micron-sized cerium oxide particles
or micron-sized cerium oxide-containing material particles using
wet chemistry techniques. In some embodiments, the micron-sized
cerium oxide particles or micron-sized cerium oxide-containing
material particles may contain 5-15% barium oxide particles. In
some embodiments, the micron-sized cerium oxide particles or
micron-sized cerium oxide-containing material particles may contain
6-12% barium oxide particles. In some embodiments, the micron-sized
cerium oxide particles or micron-sized cerium oxide-containing
material particles may contain 7-9% barium oxide particles. In some
embodiments, the micron-sized cerium oxide particles or
micron-sized cerium oxide-containing material particles may contain
about 8% barium oxide particles. In some embodiments, the
micron-sized cerium oxide-containing material comprises cerium
oxide, cerium-zirconium oxide, cerium-lanthanum oxide,
cerium-yttrium oxide, cerium-zirconium-lanthanum oxide,
cerium-zirconium-yttrium oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0.13La.sub.0.04O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide.
[0203] In some embodiments, the second particle is an NNm.TM.
particle comprising composite nanoparticles. In other embodiments,
the second particle is an NNiM particle comprising composite
nanoparticles. The following discussion will be exemplified using
NNm.TM. particles, but applies equally well to NNiM particles. The
composite nanoparticle may include one or more nanoparticles
attached to a support nanoparticle to form a "nano-on-nano"
composite nanoparticle that can trap, absorb, or store NO.sub.x
gases. Platinum group metals may be used to prepare the composite
nanoparticle. In certain embodiments, the composite nanoparticle
may contain platinum. In other embodiments, the composite
nanoparticle may contain palladium. In some embodiments, the
composite nanoparticle may contain a mixture of platinum and
palladium. A suitable support nanoparticle for the composite
nanoparticles includes, but is not limited to, nano-sized aluminum
oxide.
[0204] Each composite nanoparticle may be supported on a single
support nanoparticle or each support nanoparticle may include one
or more composite nanoparticles. The composite nanoparticles may
include platinum, palladium, or a mixture thereof. In some
embodiments, palladium is used alone. In other embodiments,
platinum may be used alone. In further embodiments, platinum may be
used in combination with palladium. For example, the nanoparticle
may contain a mixture of 5:1 to 100:1 platinum to palladium. In
some embodiments, the nanoparticle may contain a mixture of 6:1 to
75:1 platinum to palladium. In some embodiments, the nanoparticle
may contain a mixture of 7:1 to 50:1 platinum to palladium. In some
embodiments, the nanoparticle may contain a mixture of 8:1 to 25:1
platinum to palladium. In some embodiments, the nanoparticle may
contain a mixture of 9:1 to 15:1 platinum to palladium. In some
embodiments, the nanoparticle may contain a mixture of 10:1
platinum to palladium, or approximately 10:1 platinum to
palladium.
[0205] The composite nanoparticles for use as components of the
NO.sub.x trapping particles can be produced by plasma-based methods
as described above for the oxidative composite nanoparticle
catalysts and reductive composite nanoparticle catalysts. Platinum
group metals (such as platinum, palladium, or a mixture thereof)
can be introduced into the plasma reactor as a fluidized powder in
a carrier gas stream. The resulting nano-on-nano particles have
similar properties (i.e., diameter or grain size) to that of the
oxidative nano-on-nano particles and reductive nano-on-nano
particles. Typically, for NO.sub.x trapping composite
nanoparticles, platinum, palladium, or a mixture of palladium and
platinum is deposited on nano-sized aluminum oxide.
[0206] To prepare an NOx trapping particle that is a
nano-on-nano-on-micro particle (NNm), a dispersion of the composite
nanoparticles is prepared. The composite nanoparticles may be
applied to porous micron-sized cerium oxide, porous micron-sized
cerium oxide-containing material, or aluminum oxide. The
micron-sized cerium oxide may contain zirconium oxide. In some
embodiments, the micron-sized cerium oxide is substantially free of
zirconium oxide. In other embodiments, the micron-sized cerium
oxide contains up to 80% zirconium oxide. The micron-sized cerium
oxide may contain zirconium oxide. In some embodiments, the
micron-sized cerium oxide is substantially free of zirconium oxide.
In some embodiments, the micron-sized cerium oxide-containing
material comprises cerium oxide, cerium-zirconium oxide,
cerium-lanthanum oxide, cerium-yttrium oxide,
cerium-zirconium-lanthanum oxide, cerium-zirconium-yttrium oxide,
cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0 13La.sub.004O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide. In one embodiment, the nanoparticle is a PGM. In one
embodiment, the PGM is platinum, palladium, or a mixture thereof.
In another embodiment, the PGM is ruthenium. In other embodiments,
the nanoparticle is a non-PGM. In some embodiments, the non-PGM is
tungsten, molybdenum, niobium, manganese, or chromium.
[0207] The micron-sized carrier particles, impregnated with the
composite nanoparticles and nano-sized metal oxide, may be prepared
as described above for the oxidative Nano-on-Nano-on-Micro
particles and the reductive Nano-on-Nano-on-Micro particles. In
addition, the resulting properties, such as particle size, are as
described above for the oxidative NNm.TM. particles and the
reductive NNm.TM. particles.
[0208] In some embodiments, the NO.sub.x trapping particles are
multiple types of particles comprising micron-sized cerium oxide
particles or micron-sized cerium oxide-containing material
particles impregnated with barium oxide, and separate NNm.TM.
particles comprising platinum and palladium. In a preferred
embodiment, the NO.sub.x trapping particles comprise micron-sized
cerium oxide particles or micron-sized cerium oxide-containing
material particles impregnated with 8% barium oxide, and separate
NNm.TM. particles comprising platinum and palladium in a 10:1
weight ratio. In any of these embodiments, the micron-sized cerium
oxide-containing material can comprise cerium oxide,
cerium-zirconium oxide, cerium-lanthanum oxide, cerium-yttrium
oxide, cerium-zirconium-lanthanum oxide, cerium-zirconium-yttrium
oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0.13La.sub.0.04O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide.
[0209] In some instances, the weight ratio of nano-sized Pt, Pd, or
Pt/Pd:nano-sized aluminum oxide is about 5%:95%. In some instances,
the weight percentage of nano-sized Pt, Pd, or Pt/Pd is between
about 5% to about 20% nano-sized Pt, Pd, or Pt/Pd on nano-sized
aluminum oxide.
[0210] The NNm.TM. particles may contain from about 0.1% to 1.0%
Pt, Pd, or Pt/Pd by weight, or in another embodiment from about
0.4% to 0.8% by weight, or in another embodiment, about 0.5% by
weight, or in another embodiment, about 0.6% by weight, of the
total mass of the NNm.TM. particle. The NNm.TM. particles can then
be used for formulations for coating substrates, where the coated
substrates may be used in catalytic converters.
[0211] In further embodiments, the NNm.TM. particles may be
comprised of metals such as Ru, W, Mo, Nb, Mn, or Cr produced using
the plasma-based methods described above.
NO.sub.x Trapping Particles: Use of Perovskites and non-PGM Metal
Oxides
[0212] In some embodiments, the NO.sub.x trapping particles
comprise micron-sized cerium oxide particles or micron-sized cerium
oxide-containing material particles impregnated with a perovskite.
In one embodiment, the perovskite is FeBaO.sub.3. In other
embodiments, the perovskite is RuBaO.sub.3 or OsBaO.sub.3. In other
embodiments, the perovskite is FeBeO.sub.3, FeMgO.sub.3,
FeCaO.sub.3, or FeSrO.sub.3. In other embodiments, the micron-sized
cerium oxide or micron-sized cerium oxide-containing material is
impregnated with a non-platinum group metal oxide. In some
embodiments, the non-platinum group metal oxide is samarium, zinc,
copper, iron, or silver oxide. The micron-sized cerium oxide or
micron-sized cerium oxide-containing material can be impregnated
with the perovskite or non-platinum group metal oxide using wet
chemistry procedures. In some embodiments, the NO.sub.x trapping
particles comprising micron-sized cerium oxide or micron-sized
cerium oxide-containing material impregnated with a perovskite or a
non-platinum group metal oxide can further include barium oxide
particles. In other embodiments, the barium oxide particles and the
perovskite or non-platinum group metal oxide are on the same
micron-sized cerium oxide particle or micron-sized cerium
oxide-containing material particle. In other embodiments, the
barium oxide particles and the perovskite or non-platinum group
metal oxide are on different micron-sized cerium oxide particles or
micron-sized cerium oxide-containing material particles. In some
embodiments, the micron-sized cerium oxide-containing material
comprises cerium oxide, cerium-zirconium oxide, cerium-lanthanum
oxide, cerium-yttrium oxide, cerium-zirconium-lanthanum oxide,
cerium-zirconium-yttrium oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0.13La.sub.0.04O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide.
Substrates
[0213] The initial substrate is preferably a catalytic converter
substrate that demonstrates good thermal stability, including
resistance to thermal shock, and to which the described washcoats
can be affixed in a stable manner. Suitable substrates include, but
are not limited to, substrates formed from cordierite or other
ceramic materials, and substrates formed from metal. The substrates
may include a grid array structure or coiled foil structure, which
provide numerous channels and result in a high surface area. The
high surface area of the coated substrate with its applied
washcoats in the catalytic converter provides for effective
treatment of the exhaust gas flowing through the catalytic
converter. A corner fill layer, or a buffer layer or adhesion layer
such as a thin Boehmite layer, may be applied to the substrate
prior to applying any of the active washcoat layers, but is not
required.
Washcoat Comprising Catalytically Active Composite
Nanoparticles
[0214] The catalytically active particles bound to support
particles can be applied to a substrate of a catalytic converter as
part of a washcoat. In some embodiments, the catalytically active
particles are nano-on-nano-on-micro particles (NNm particles). In
other embodiments, the catalytically active particles are
nano-on-nano-in-micro particles (NNiM particles). The catalytically
active particles are reactive to different gases in the exhausts.
For example, catalytically active particles containing platinum
and/or palladium nanoparticles supported on aluminum oxide are
oxidative to the hydrocarbon gases and carbon monoxide, whereas
catalytically active particles containing rhodium supported on
cerium oxide are reductive to the nitrogen oxides.
[0215] The NO.sub.x trapping particles can be applied to a
substrate of a catalytic converter as part of a washcoat. The
NO.sub.x trapping particles store nitrogen oxide gases during
lean-burn engine operation. In some embodiments, the nano-sized
barium oxide particles or micron-sized barium oxide particles used
with the alumina supports are included in the washcoat as an
absorber. In other embodiments, the nano-sized barium oxide
particles or micron-sized barium oxide particles used with the
cerium oxide supports are included in the washcoat as an absorber.
In other embodiments, the nano-sized barium oxide particles or
micron-sized barium oxide particles used with the
cerium/zirconium/lanthanum/yttrium oxide supports are included in
the washcoat as an absorber. In other embodiments, any combination
of NO.sub.x trapping particles containing barium oxide particles,
PGM and/or non-PGM can be included in the washcoat to trap NO.sub.x
gases.
[0216] The washcoat may contain oxidative nanoparticles, reductive
nanoparticles, or NO.sub.x trapping particles. A washcoat
containing oxidative nanoparticles on micron supports or reductive
nanoparticles on micron supports may be used to coat a substrate
such that the oxidative catalytically active particles bearing
composite nanoparticles and reductive catalytically active
particles bearing composite nanoparticles are in separate washcoat
layers on the substrate. A washcoat containing reductive
nanoparticles on micron supports or NO.sub.x trapping particles may
be used to coat a substrate such that the reductive catalytically
active particles bearing composite nanoparticles and NO.sub.x
trapping particles are in either the same or in a separate washcoat
layer on the substrate. In one embodiment, a washcoat containing
reductive nanoparticles comprised of rhodium on micron supports is
substantially free of NO.sub.x trapping particles bearing composite
nanoparticles comprised of platinum. In one embodiment, a washcoat
containing reductive nanoparticles on micron supports is
substantially free of NO.sub.x trapping particles bearing composite
nanoparticles comprised of palladium.
[0217] The washcoat layers can include materials that are less
active or inert to exhausts. Such materials can be incorporated as
supports for the reactive catalysts or to provide surface area for
the metals. In some embodiments, the catalyst-containing washcoat
composition further includes "spacer" or "filler" particles, where
the spacer particles may, for example, be ceramic, metal oxide, or
metallic particles. In some embodiments, the spacer particles may
be alumina or boehmite.
[0218] In certain embodiments, the washcoat layer can contain an
oxygen storage component. An oxygen storage component has oxygen
storage capacity with which the catalyst can accumulate oxygen when
exhaust gas is in an oxygen-excess state (oxidative atmosphere),
and releases the accumulated oxygen when exhaust gas is in an
oxygen-deficient state (reductive atmosphere). With an oxygen
storage component, carbon monoxide and hydrocarbons can be
efficiently oxidized to CO.sub.2 even in an oxygen-deficient state.
Materials such as cerium oxide or cerium oxide-containing material
can be used as oxygen storage components. The cerium oxide
particles may contain zirconium oxide. In a preferred embodiment,
the cerium oxide particles are substantially free of zirconium
oxide. In other embodiments, the cerium oxide particles contain up
to 60% zirconium oxide. In some embodiments, the cerium oxide
particles may contain both zirconium oxide and lanthanum. In some
embodiments, the cerium oxide particles contain 40-80% cerium
oxide, 10-50% zirconium oxide, and 10% lanthanum. In one
embodiment, the cerium oxide particles contain 80% cerium oxide,
10% zirconium oxide, and 10% lanthanum. In another embodiment, the
cerium oxide particles contain 40% cerium oxide, 50% zirconium
oxide, and 10% lanthanum. In some embodiments, micron-sized cerium
oxide or micron-sized cerium oxide-containing material is included
in the washcoat as an oxygen storage component. In other
embodiments, oxygen storage component particles are used that
comprise cerium oxide, cerium-zirconium oxide, cerium-lanthanum
oxide, cerium-yttrium oxide, cerium-zirconium-lanthanum oxide,
cerium-zirconium-yttrium oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the oxygen storage component particles comprise
Ce.sub.0o.83Zr.sub.0.13La.sub.0.04O. In some preferred embodiments,
the oxygen storage component particles comprise a material that
comprises about 86% cerium oxide, 10% zirconium oxide, and 4%
lanthanum oxide. In some preferred embodiments, the oxygen storage
component particles comprise
Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some preferred
embodiments, oxygen storage component particles comprise a material
that comprises about 40% cerium oxide, 50% zirconium oxide, 5%
lanthanum oxide, and 5% yttrium oxide.
Washcoat Comprising NO.sub.x Storage Particles
[0219] The NO.sub.x trapping particles can be applied to a
substrate of a catalytic converter as part of a washcoat. The
NO.sub.x trapping particles store nitrogen oxide gases during
lean-burn engine operation. In some embodiments, the NO.sub.x
trapping particles in the NO.sub.x storage washcoat can be
micron-sized cerium oxide or micron-sized cerium oxide-containing
material containing barium oxide. The barium oxide can be
nano-sized or micron-sized, as described above. In some
embodiments, the NO.sub.x trapping particles can be micron-sized
cerium oxide particles or micron-sized cerium oxide-containing
material particles impregnated with platinum, palladium, or a
mixture thereof. In some embodiments, the NO.sub.x trapping
particles can be micron-sized cerium oxide particles or
micron-sized cerium oxide-containing material particles impregnated
with barium oxide in addition to platinum, palladium, or a mixture
thereof. In some embodiments, the barium oxide and platinum,
palladium, or mixture thereof are added to the micron-sized cerium
oxide or micron-sized cerium oxide-containing material using wet
chemistry techniques. In some embodiments, the barium oxide and the
PGM are on the same micron-sized cerium oxide particle or
micron-sized cerium oxide-containing material particle. In other
embodiments, the barium oxide and the PGM are on different
micron-sized cerium oxide particles or micron-sized cerium
oxide-containing material particles. In any of the disclosed
embodiments, the micron-sized cerium oxide-containing material can
comprise cerium oxide, cerium-zirconium oxide, cerium-lanthanum
oxide, cerium-yttrium oxide, cerium-zirconium-lanthanum oxide,
cerium-zirconium-yttrium oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0.13La.sub.0.04O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide.
[0220] In other embodiments, the NO.sub.x trapping particles can be
different types of particles. In some embodiments, the NO.sub.x
trapping particles include micron-sized cerium oxide particles or
micron-sized cerium oxide-containing material particles impregnated
with barium oxide and separate NNm or NNiM particles. In one
embodiment, the NNm particles are platinum group metals supported
on aluminum oxide. In another embodiment, the NNiM particles are
platinum group metals supported on aluminum oxide. In some
embodiments, the platinum group metal is Pt, Pd, or a mixture
thereof. In any of the disclosed embodiments, the micron-sized
cerium oxide-containing material can comprise cerium oxide,
cerium-zirconium oxide, cerium-lanthanum oxide, cerium-yttrium
oxide, cerium-zirconium-lanthanum oxide, cerium-zirconium-yttrium
oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0.13La.sub.0.04O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide.
[0221] In other embodiments, the NNm or NNiM particles include Ru,
W, Mo, Nb, Mn, or Cr. In further embodiments, the NO.sub.x trapping
particles in the NO.sub.x storage washcoat can be micron-sized
cerium oxide particles or micron-sized cerium oxide-containing
material particles impregnated with a perovskite. The perovskite
can be FeBaO.sub.3, RuBaO.sub.3, OsBaO.sub.3, FeBeO.sub.3,
FeMgO.sub.3, FeCaO.sub.3, or FeSrO.sub.3. In other embodiments, the
micron-sized cerium oxide or micron-sized cerium oxide-containing
material is impregnated with a non-platinum group metal oxide. In
some embodiments, the non-platinum group metal oxide is samarium,
zinc, copper, iron, or silver oxide. Typically, the micron-sized
cerium oxide or micron-sized cerium oxide-containing material is
impregnated with the perovskite or non-platinum group metal oxide
using wet chemistry procedures. In any of the disclosed
embodiments, the micron-sized cerium oxide-containing material can
comprise cerium oxide, cerium-zirconium oxide, cerium-lanthanum
oxide, cerium-yttrium oxide, cerium-zirconium-lanthanum oxide,
cerium-zirconium-yttrium oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0.13La.sub.0.04O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide.
[0222] The washcoat containing NO.sub.x trapping particles may be
used to coat a substrate such that NO.sub.x trapping particles and
the reductive catalytically active particles bearing composite
nanoparticles are in either the same or in separate washcoat layers
on the substrate.
[0223] The washcoat layers can include materials that are less
active or inert to exhausts. Such materials can be incorporated as
supports for the reactive catalysts or to provide surface area for
the metals. In some embodiments, the catalyst-containing washcoat
composition further includes "spacer" or "filler" particles, where
the spacer particles may, for example, be ceramic, metal oxide, or
metallic particles. In some embodiments, the spacer particles may
be boehmite.
[0224] In certain embodiments, the washcoat layer can contain an
oxygen storage component. An oxygen storage component has oxygen
storage capacity with which the catalyst can accumulate oxygen when
exhaust gas is in an oxygen-excess state (oxidative atmosphere),
and releases the accumulated oxygen when exhaust gas is in an
oxygen-deficient state (reductive atmosphere). With an oxygen
storage component, carbon monoxide and hydrocarbons can be
efficiently oxidized to CO.sub.2 even in an oxygen-deficient state.
Materials such as cerium oxide or cerium-oxide containing material
can be used as oxygen storage components. The cerium oxide
particles may contain zirconium oxide. In a preferred embodiment,
the cerium oxide particles are substantially free of zirconium
oxide. The micron-sized cerium oxide-containing material can
comprise cerium oxide, cerium-zirconium oxide, cerium-lanthanum
oxide, cerium-yttrium oxide, cerium-zirconium-lanthanum oxide,
cerium-zirconium-yttrium oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0.13La.sub.0.04O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide. In some embodiments, micron-sized cerium oxide or
micron-sized cerium oxide-containing material is included in the
washcoat as an oxygen storage component.
[0225] In the following washcoat descriptions, the composite
nanoparticles are described as a component of the NNm.TM. particles
for illustrative purposes only. However, the composite
nanoparticles could equally well be a component of the NNiM
particles. In the following descriptions, the percentages of the
components of the washcoat compositions are provided in terms of
the amount of solids present in the washcoat compositions, as the
washcoat compositions can be provided in an aqueous suspension or,
in some instances, as dry powder. The catalyst layer (or
catalyst-containing layer) refers to the catalyst-containing
washcoat composition after it has been applied to the substrate,
dried, and calcined. The catalyst layer referred to herein
encompasses a layer including oxidative catalytically active
particles or a layer including reductive catalytically active
particles. The NO.sub.x storage layer refers to the NO.sub.x
trapping particle-containing washcoat composition after it has been
applied to the substrate, dried, and calcined.
[0226] The following Table 1 provides embodiments of different
washcoat layer configurations:
TABLE-US-00001 TABLE 1 Washcoat Configurations Two-layer Washcoat
Configurations-Separate Three-layer Washcoat Configurations-
Oxidation and Reduction Washcoat Layers, Separate Oxidation,
Reduction and NO.sub.x Combined Reduction and NO.sub.x Storage
Layer Storage Washcoat Layers 1) Substrate-Oxidizing Washcoat
Layer- 3) Substrate-Reducing Washcoat Layer- Combined
Reducing/NO.sub.x Storage Washcoat Oxidizing Washcoat
Layer-NO.sub.x Storage Layer Washcoat Layer 2) Substrate-Combined
Reducing/NO.sub.x Storage 4) Substrate-Reducing Washcoat
Layer-NO.sub.x Washcoat Layer-Oxidizing Washcoat Layer Storage
Washcoat Layer-Oxidizing Washcoat Layer 5) Substrate-Oxidizing
Washcoat Layer- Reducing Washcoat Layer-NO.sub.x Storage Washcoat
Layer 6) Substrate-Oxidizing Washcoat Layer-NO.sub.x Storage
Washcoat Layer-Reducing Washcoat Layer 7) Substrate-NO.sub.x
Storage Washcoat Layer- Reducing Washcoat Layer-Oxidizing Washcoat
Layer 8) Substrate-NO.sub.x Storage Washcoat Layer- Oxidizing
Washcoat Layer-Reducing Washcoat Layer
Two-layer Washcoat Configurations-Separate Oxidation and Reduction
Washcoat Layers, Combined Reduction and NO.sub.x Storage Layer
Oxidation Washcoat Components
[0227] In some embodiments, the oxidizing washcoat layer in the
two-layer configurations (configurations 1-2 in Table 1) comprises,
consists essentially of, or consists of oxidizing
nano-on-nano-on-micro (NNm.TM.) particles, boehmite particles, and
alumina filler/sealant particles (for example MI-386) with or
without BaO. The composition of the oxidizing washcoat components
and the reducing washcoat components may be as described below
regardless of the order in which the washcoats are deposited.
[0228] In some embodiments, the NNm.TM. particles make up between
approximately 35% to approximately 75% by weight of the combination
of the NNm.TM. particles, boehmite particles, and alumina
filler/sealant particles. In some embodiments, the NNm.TM.
particles make up between approximately 40% to approximately 60% by
weight of the combination of the NNm.TM. particles, boehmite
particles, and alumina filler/sealant particles. In some
embodiments, the NNm.TM. particles make up between approximately
45% to approximately 55% by weight of the combination of the
NNm.TM. particles, boehmite particles, and alumina filler/sealant
particles. In some embodiments, the NNm.TM. particles make up about
50% by weight of the combination of the NNm.TM. particles, boehmite
particles, and alumina filler/sealant particles. Preferably, the
catalytically active particle in the oxidizing NNm.TM. particles is
a mixture of platinum and palladium at a loading of 2-3 wt % in the
NNm.TM. particles. Palladium, platinum, and palladium/platinum
mixtures may also be used in the loadings described previously.
[0229] In some embodiments, the boehmite particles make up between
approximately 0.5% to approximately 10% by weight of the
combination of the NNm.TM. particles, boehmite particles, and
alumina filler/sealant particles. In some embodiments, the boehmite
particles make up between approximately 1% to approximately 7% by
weight of the combination of the NNm.TM. particles, boehmite
particles, and alumina filler/sealant particles. In some
embodiments, the boehmite particles make up between approximately
2% to approximately 5% by weight of the combination of the NNm.TM.
particles, boehmite particles, and alumina filler/sealant
particles. In some embodiments, the boehmite particles make up
about 3% by weight of the combination of the NNm.TM. particles,
boehmite particles, and alumina filler/sealant particles.
[0230] In some embodiments, the alumina filler/sealant particles
make up between approximately 30% to approximately 70% by weight of
the combination of the NNm.TM. particles, boehmite particles, and
alumina filler/sealant particles. In some embodiments, the alumina
filler/sealant particles make up between approximately 40% to
approximately 60% by weight of the combination of the NNm.TM.
particles, boehmite particles, and alumina filler/sealant
particles. In some embodiments, the alumina filler/sealant
particles make up between approximately 45% to approximately 55% by
weight of the combination of the NNm.TM. particles, boehmite
particles, and alumina filler/sealant particles. In some
embodiments, the alumina filler/sealant particles make up about 50%
by weight of the combination of the NNm.TM. particles, boehmite
particles, and alumina filler/sealant particles. The alumina
filler/sealant particles may be porous lanthanum-stabilized
alumina, for example MI-386. In some embodiments, a different
filler particle may be used in place of some or all of the alumina
particles.
[0231] In the oxidizing washcoat, from 0 to 100% of the alumina
filler/sealant particles may be alumina impregnated with nano-sized
BaO particles, alumina mixed with micron-sized BaO particles, or
both alumina impregnated with nano-sized BaO particles and admixed
with micron-sized BaO particles. In some embodiments, from 1 wt
%-100 wt %, from 20 wt %-80 wt %, or from 30 wt %-60 wt %
micron-sized BaO may be used in place of non-BaO-impregnated
alumina. In some embodiments, a 50:50 mixture of regular MI-386 and
BaO-impregnated MI-386 (impregnated with nano-sized BaO particles),
or a 50:50 mixture of MI-386 and micron-sized BaO particles, or a
mixture of MI-386 impregnated with nano-sized BaO particles and
admixed with micron-sized BaO particles, may be used for this
component of the washcoat. In some embodiments, the alumina can
comprise from 5% to 30% nano-BaO-impregnated alumina and from 70%
to 95% non-BaO-impregnated alumina. In some embodiments, the
alumina can comprise from 5% to 20% nano-BaO-impregnated alumina
and from 80% to 95% non-BaO-impregnated alumina. In some
embodiments, the alumina can comprise from 8% to 16%
nano-BaO-impregnated alumina and from 84% to 92%
non-BaO-impregnated alumina. In one embodiment, 12%, or about 12%,
nano-BaO-impregnated alumina is mixed with 88%, or about 88%,
alumina without impregnated BaO. In one embodiment, 15%, or about
15%, nano-BaO-impregnated alumina is mixed with 85%, or about 85%,
alumina without impregnated BaO.
[0232] In some embodiments, the alumina can comprise from 5% to 30%
micron-sized BaO and from 70% to 95% non-BaO-impregnated alumina.
In some embodiments, the alumina can comprise from 5% to 20%
micron-sized BaO and from 80% to 95% non-BaO-impregnated alumina.
In some embodiments, the alumina can comprise from 8% to 16%
micron-sized-BaO and from 84% to 92% non-BaO-impregnated alumina.
In one embodiment, 12%, or about 12%, micron-sized BaO is mixed
with 88%, or about 88%, alumina without impregnated BaO. In one
embodiment, 15%, or about 15%, micron-sized BaO is mixed with 85%,
or about 85%, alumina without impregnated BaO.
[0233] The ranges for the nano-sized BaO-alumina ratio, that is,
the amount of nano-BaO impregnated into the alumina, include 1-25%
BaO to 75% to 99% aluminum oxide micron support; 3-20% BaO to 80%
to 97% aluminum oxide micron support; 5%-15% BaO to 85% to 95%
aluminum oxide micron support; and about 15% BaO to about 85%
aluminum oxide micron support, expressed as weight percentages. In
one embodiment, the nano-BaO-impregnated aluminum oxide comprises
15%, or about 15%, nano-BaO by weight and 85%, or about 85%,
aluminum oxide by weight.
Combined Reducing and NO.sub.x Storage Washcoat Components
[0234] In some embodiments, the combined reducing and NO.sub.x
storage washcoat layer in the two-layer configurations
(configurations 1-2 in Table 1) comprises, consists essentially of,
or consists of reducing nano-on-nano-on-micro (NNm.TM.) particles,
boehmite particles, and cerium oxide particles (for example HSA5)
or cerium oxide-containing material particles for temporarily
storing NO.sub.x gases. In some embodiments, the cerium oxide
particles or cerium oxide-containing material particles contain Pt,
Pd, or a mixture of Pt/Pd. In some embodiments, the cerium oxide
particles or cerium oxide-containing material particles contain
barium oxide. In some embodiments, the cerium oxide particles or
cerium oxide-containing material particles contain barium oxide in
addition to Pt, Pd, or a mixture of Pt/Pd. In any of the disclosed
embodiments, the micron-sized cerium oxide-containing material can
comprise cerium oxide, cerium-zirconium oxide, cerium-lanthanum
oxide, cerium-yttrium oxide, cerium-zirconium-lanthanum oxide,
cerium-zirconium-yttrium oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0.13La.sub.0.04O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide.
[0235] In other embodiments, the cerium oxide particles or cerium
oxide-containing material particles can contain Ru, W, Mo, Nb, Mn,
or Cr. In further embodiments, the cerium oxide particles or cerium
oxide-containing material particles can contain a perovskite, such
as FeBaO.sub.3. In still other embodiments, the cerium oxide
particles can contain an oxide of Sm, Zn, Cu, Fe, or Ag. In some
embodiments, the cerium oxide particles or cerium oxide-containing
material particles can contain any combination of Ru, Pt, Pd,
Pt/Pd, FeBaO.sub.3, W, Mo, Nb, Mn, Cr, Sm, Zn, Cu, Fe, Ag, and
barium oxide as described above. In any of the disclosed
embodiments, the micron-sized cerium oxide-containing material can
comprise cerium oxide, cerium-zirconium oxide, cerium-lanthanum
oxide, cerium-yttrium oxide, cerium-zirconium-lanthanum oxide,
cerium-zirconium-yttrium oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0.13La.sub.0.04O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide.
[0236] In some embodiments, the reducing NNm.TM. particles make up
between approximately 3% to approximately 40% by weight of the
combination of the NNm.TM. particles, boehmite particles, and
cerium oxide particles or cerium oxide-containing material
particles. In some embodiments, the NNm.TM. particles make up
between approximately 5% to approximately 30% by weight of the
combination of the NNm.TM. particles, boehmite particles, and
cerium oxide particles or cerium oxide-containing material
particles. In some embodiments, the NNm.TM. particles make up
between approximately 10% to approximately 20% by weight of the
combination of the NNm.TM. particles, boehmite particles, and
cerium oxide particles or cerium oxide-containing material
particles. In some embodiments, the NNm.TM. particles make up about
15% by weight of the combination of the NNm.TM. particles, boehmite
particles, and cerium oxide particles or cerium oxide-containing
material particles. In one embodiment, the catalytically active
particle in the NNm.TM. particles comprises rhodium at a loading of
about 0.2 wt % to 0.5 wt % in the NNm.TM. particles. In another
embodiment, the catalytically active particle in the NNm.TM.
particles is rhodium at a loading of about 0.3 wt % in the NNm.TM.
particles. In another embodiment, the catalytically active particle
in the NNm.TM. particles is rhodium at a loading of about 0.4 wt %
in the NNm.TM. particles. Other loadings described previously may
also be used. In any of the disclosed embodiments, the micron-sized
cerium oxide-containing material can comprise cerium oxide,
cerium-zirconium oxide, cerium-lanthanum oxide, cerium-yttrium
oxide, cerium-zirconium-lanthanum oxide, cerium-zirconium-yttrium
oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0.13La.sub.0.04O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide.
[0237] In some embodiments, the micron-sized porous cerium oxide
particles make up between approximately 30% to approximately 98% by
weight of the combination of the NNm.TM. particles, boehmite
particles, and cerium oxide particles or cerium oxide-containing
material particles. In some embodiments, the micron-sized porous
cerium oxide particles make up between approximately 50% to
approximately 95% by weight of the combination of the NNm.TM.
particles, boehmite particles, and cerium oxide particles or cerium
oxide-containing material particles. In some embodiments, the
micron-sized porous cerium oxide particles or cerium
oxide-containing material particles make up between approximately
70% to approximately 90% by weight of the combination of the
NNm.TM. particles, boehmite particles, and cerium oxide particles
or cerium oxide-containing material particles. In some embodiments,
the micron-sized porous cerium oxide particles make up between
approximately 80% to approximately 85% by weight of the combination
of the NNm.TM. particles, boehmite, and cerium oxide particles or
cerium oxide-containing material particles. In some embodiments,
the micron-sized porous cerium oxide particles make up about 85% by
weight of the combination of the NNm.TM. particles, boehmite, and
cerium oxide particles or cerium oxide-containing material
particles. In any of the disclosed embodiments, the micron-sized
cerium oxide-containing material can comprise cerium oxide,
cerium-zirconium oxide, cerium-lanthanum oxide, cerium-yttrium
oxide, cerium-zirconium-lanthanum oxide, cerium-zirconium-yttrium
oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0.13La.sub.0.04O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide.
[0238] In some embodiments, the boehmite particles make up between
approximately 0.5% to approximately 10% by weight of the
combination of the NNm.TM. particles, boehmite particles, and
cerium oxide particles or cerium oxide-containing material
particles. In some embodiments, the boehmite particles make up
between approximately 1% to approximately 7% by weight of the
combination of the NNm.TM. particles, boehmite particles, and
cerium oxide particles or cerium oxide-containing material
particles. In some embodiments, the boehmite particles make up
between approximately 2% to approximately 5% by weight of the
combination of the NNm.TM. particles, boehmite particles, and
cerium oxide particles or cerium oxide-containing material
particles. In some embodiments, the boehmite particles make up
about 3% by weight of the combination of the NNm.TM. particles,
boehmite particles, and cerium oxide particles or cerium
oxide-containing material particles. In any of the disclosed
embodiments, the micron-sized cerium oxide-containing material can
comprise cerium oxide, cerium-zirconium oxide, cerium-lanthanum
oxide, cerium-yttrium oxide, cerium-zirconium-lanthanum oxide,
cerium-zirconium-yttrium oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0.13La.sub.0.04O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide.
[0239] In the combined reducing and NO.sub.x storage washcoat, from
0 to 100% of the cerium oxide particles may be cerium oxide or
cerium oxide-containing material impregnated with nano-sized BaO
particles, cerium oxide particles or cerium oxide-containing
material particles mixed with micron-sized BaO particles, or both
cerium oxide particles or cerium oxide-containing material
particles impregnated with nano-sized BaO particles and admixed
with micron-sized BaO particles. In some embodiments, from 1 wt
%-100 wt %, from 20 wt %-80 wt %, or from 30 wt %-60 wt %
micron-sized BaO may be used in place of non-BaO-impregnated
alumina. In some embodiments, a 50:50 mixture of regular HSAS and
BaO impregnated HSAS (impregnated with nano-sized BaO particles),
or a 50:50 mixture of HSAS and micron-sized BaO particles, or a
mixture of HSAS impregnated with nano-sized BaO particles and
admixed with micron-sized BaO particles, may be used for this
component of the washcoat. In some embodiments, the cerium oxide
particles can comprise from 5% to 30% nano-BaO-impregnated cerium
oxide and from 70% to 95% non-BaO-impregnated cerium oxide. In some
embodiments, the cerium oxide particles can comprise from 5% to 20%
nano-BaO-impregnated cerium oxide and from 80% to 95%
non-BaO-impregnated cerium oxide. In some embodiments, the cerium
oxide particles can comprise from 8% to 16% nano-BaO-impregnated
cerium oxide and from 84% to 92% non-BaO-impregnated cerium oxide.
In one embodiment, 12%, or about 12%, nano-BaO-impregnated cerium
oxide is mixed with 88%, or about 88%, cerium oxide without
impregnated BaO. In one embodiment, 8%, or about 8%,
nano-BaO-impregnated cerium oxide is mixed with 92%, or about 92%,
cerium oxide without impregnated BaO. In any of the disclosed
embodiments, the micron-sized cerium oxide-containing material can
comprise cerium oxide, cerium-zirconium oxide, cerium-lanthanum
oxide, cerium-yttrium oxide, cerium-zirconium-lanthanum oxide,
cerium-zirconium-yttrium oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0.13La.sub.0.04O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide.
Three-layer Washcoat Configuration: Separate Oxidation, Reduction
and NO.sub.x Storage Washcoat Components
Oxidation Washcoat Components
[0240] In some embodiments, the oxidizing washcoat layer in the
three-layer configurations (configurations 3-8 in Table 1)
comprises, consists essentially of, or consists of oxidizing
nano-on-nano-on-micro (NNm.TM.) particles, boehmite particles, and
alumina filler/sealant particles (for example MI-386) with or
without BaO. The composition of the oxidizing washcoat components
and the reducing washcoat components may be as described below
regardless of the order in which the washcoats are deposited.
[0241] In some embodiments, the NNm.TM. particles make up between
approximately 35% to approximately 75% by weight of the combination
of the NNm.TM. particles, boehmite particles, and alumina
filler/sealant particles. In some embodiments, the NNm.TM.
particles make up between approximately 40% to approximately 60% by
weight of the combination of the NNm.TM. particles, boehmite
particles, and alumina filler/sealant particles. In some
embodiments, the NNm.TM. particles make up between approximately
45% to approximately 55% by weight of the combination of the
NNm.TM. particles, boehmite particles, and alumina filler/sealant
particles. In some embodiments, the NNm.TM. particles make up about
50% by weight of the combination of the NNm.TM. particles, boehmite
particles, and alumina filler/sealant particles. Preferably, the
catalytically active particle in the oxidizing NNm.TM. particles is
a mixture of platinum and palladium at a loading of 2-3 wt % in the
NNm.TM. particles. Palladium, platinum, and palladium/platinum
mixtures may also be used in the loadings described previously.
[0242] In some embodiments, the boehmite particles make up between
approximately 0.5% to approximately 10% by weight of the
combination of the NNm.TM. particles, boehmite particles, and
alumina filler/sealant particles. In some embodiments, the boehmite
particles make up between approximately 1% to approximately 7% by
weight of the combination of the NNm.TM. particles, boehmite
particles, and alumina filler/sealant particles. In some
embodiments, the boehmite particles make up between approximately
2% to approximately 5% by weight of the combination of the NNm.TM.
particles, boehmite particles, and alumina filler/sealant
particles. In some embodiments, the boehmite particles make up
about 3% by weight of the combination of the NNm.TM. particles,
boehmite particles, and alumina filler/sealant particles.
[0243] In some embodiments, the alumina filler/sealant particles
make up between approximately 30% to approximately 70% by weight of
the combination of the NNm.TM. particles, boehmite particles, and
alumina filler/sealant particles. In some embodiments, the alumina
filler/sealant particles make up between approximately 40% to
approximately 60% by weight of the combination of the NNm.TM.
particles, boehmite particles, and alumina filler/sealant
particles. In some embodiments, the alumina filler/sealant
particles make up between approximately 45% to approximately 55% by
weight of the combination of the NNm.TM. particles, boehmite
particles, and alumina filler/sealant particles. In some
embodiments, the alumina filler/sealant particles make up about 50%
by weight of the combination of the NNm.TM. particles, boehmite
particles, and alumina filler/sealant particles. The alumina
filler/sealant particles may be porous lanthanum-stabilized
alumina, for example MI-386. In some embodiments, a different
filler particle may be used in place of some or all of the alumina
particles.
[0244] In the oxidizing washcoat, from 0 to 100% of the alumina
filler/sealant particles may be alumina impregnated with nano-sized
BaO particles, alumina mixed with micron-sized BaO particles, or
both alumina impregnated with nano-sized BaO particles and admixed
with micron-sized BaO particles. In some embodiments, from 1 wt
%-100 wt %, from 20 wt %-80 wt %, or from 30 wt %-60 wt %
micron-sized BaO may be used in place of non-BaO-impregnated
alumina. In some embodiments, a 50:50 mixture of regular MI-386 and
BaO-impregnated MI-386 (impregnated with nano-sized BaO particles),
or a 50:50 mixture of MI-386 and micron-sized BaO particles, or a
mixture of MI-386 impregnated with nano-sized BaO particles and
admixed with micron-sized BaO particles, may be used for this
component of the washcoat. In some embodiments, the alumina can
comprise from 5% to 30% nano-BaO-impregnated alumina and from 70%
to 95% non-BaO-impregnated alumina. In some embodiments, the
alumina can comprise from 5% to 20% nano-BaO-impregnated alumina
and from 80% to 95% non-BaO-impregnated alumina. In some
embodiments, the alumina can comprise from 8% to 16%
nano-BaO-impregnated alumina and from 84% to 92%
non-BaO-impregnated alumina. In one embodiment, 12%, or about 12%,
nano-BaO-impregnated alumina is mixed with 88%, or about 88%,
alumina without impregnated BaO. In one embodiment, 10%, or about
10%, nano-BaO-impregnated alumina is mixed with 90%, or about 90%,
alumina without impregnated BaO.
[0245] In some embodiments, the alumina can comprise from 5% to 30%
micron-sized BaO and from 70% to 95% non-BaO-impregnated alumina.
In some embodiments, the alumina can comprise from 5% to 20%
micron-sized BaO and from 80% to 95% non-BaO-impregnated alumina.
In some embodiments, the alumina can comprise from 8% to 16%
micron-sized-BaO and from 84% to 92% non-BaO-impregnated alumina.
In one embodiment, 12%, or about 12%, micron-sized BaO is mixed
with 88%, or about 88%, alumina without impregnated BaO. In one
embodiment, 15%, or about 15%, micron-sized BaO is mixed with 85%,
or about 85%, alumina without impregnated BaO.
[0246] The ranges for the nano-sized BaO-alumina ratio, that is,
the amount of nano-BaO impregnated into the alumina, include 1-25%
BaO to 75% to 99% aluminum oxide micron support; 3-20% BaO to 80%
to 97% aluminum oxide micron support; 5%-15% BaO to 85% to 95%
aluminum oxide micron support; and about 15% BaO to about 85%
aluminum oxide micron support, expressed as weight percentages. In
one embodiment, the nano-BaO-impregnated aluminum oxide comprises
15%, or about 15%, nano-BaO by weight and 85%, or about 85%,
aluminum oxide by weight.
Reducing Washcoat Components
[0247] In some embodiments, the reducing washcoat layer in the
three-layer configurations (configurations 3-8 in Table 1)
comprises, consists essentially of, or consists of reducing
nano-on-nano-on-micro (NNm.TM.) particles, boehmite particles, and
alumina filler/sealant particles (for example MI-386).
[0248] In some embodiments, the reducing NNm.TM. particles make up
between approximately 50% to approximately 95% by weight of the
combination of the NNm.TM. particles, boehmite particles, and
alumina filler/sealant particles. In some embodiments, the NNm.TM.
particles make up between approximately 60% to approximately 90% by
weight of the combination of the NNm.TM. particles, boehmite
particles, and alumina filler/sealant particles. In some
embodiments, the NNm.TM. particles make up between approximately
75% to approximately 85% by weight of the combination of the
NNm.TM. particles, boehmite particles, and alumina filler/sealant
particles. In some embodiments, the NNm.TM. particles make up about
80% by weight of the combination of the NNm.TM. particles, boehmite
particles, and alumina filler/sealant particles. In some
embodiments, the catalytically active particle in the NNm.TM.
particles is rhodium at a loading of about 0.3-2 wt % in the
NNm.TM. particles. In some embodiments, the catalytically active
particle in the NNm.TM. particles is rhodium at a loading of about
0.3-1 wt % in the NNm.TM. particles. In some embodiments, the
catalytically active particle in the NNm.TM. particles is rhodium
at a loading of about 0.3-0.5 wt % in the NNm.TM. particles. In one
embodiment, the catalytically active particle in the NNm.TM.
particles is rhodium at a loading of about 0.3 wt % in the NNm.TM.
particles. Other loadings described previously may also be
used.
[0249] In some embodiments, the alumina filler/sealant particles
make up between approximately 5% to approximately 40% by weight of
the combination of the NNm.TM. particles, boehmite particles, and
alumina filler/sealant particles. In some embodiments, the alumina
filler/sealant particles make up between approximately 10% to
approximately 30% by weight of the combination of the NNm.TM.
particles, boehmite particles, and alumina filler/sealant
particles. In some embodiments, the alumina filler/sealant
particles make up between approximately 15% to approximately 20% by
weight of the combination of the NNm.TM. particles, boehmite
particles, and alumina filler/sealant particles. In some
embodiments, the alumina filler/sealant particles make up about 17%
by weight of the combination of the NNm.TM. particles, boehmite
particles, and alumina filler/sealant particles. The alumina
filler/sealant particles may be porous lanthanum-stabilized
alumina, for example MI-386. In some embodiments, a different
filler particle may be used in place of some or all of the alumina
particles.
[0250] In some embodiments, the boehmite particles make up between
approximately 0.5% to approximately 10% by weight of the
combination of the NNm.TM. particles, boehmite particles, and
alumina filler/sealant particles. In some embodiments, the boehmite
particles make up between approximately 1% to approximately 7% by
weight of the combination of the NNm.TM. particles, boehmite
particles, and alumina filler/sealant particles. In some
embodiments, the boehmite particles make up between approximately
2% to approximately 5% by weight of the combination of the NNm.TM.
particles, boehmite particles, and alumina filler/sealant
particles. In some embodiments, the boehmite particles make up
about 3% by weight of the combination of the NNm.TM. particles,
boehmite particles, and alumina filler/sealant particles.
NO.sub.x Storage Washcoat Components
[0251] In some embodiments, the NO.sub.x storage washcoat layer in
the three-layer configurations (configurations 3-8 in Table 1)
comprises, consists essentially of, or consists of
nano-on-nano-on-micro (NNm.TM.) particles, boehmite particles, and
cerium oxide particles (for example HSAS) or cerium
oxide-containing material particles for temporarily storing
NO.sub.x gases. In some embodiments, the nano-on-nano-on-micro
(NNm.TM.) particles contain platinum, palladium, or a mixture
thereof. In one embodiment, the nano-on-nano-on-micro (NNm.TM.)
particles contain a mixture of Pt and Pd. In some embodiments, the
cerium oxide particles or cerium oxide-containing material
particles contain barium oxide. In any of the disclosed
embodiments, the micron-sized cerium oxide-containing material can
comprise cerium oxide, cerium-zirconium oxide, cerium-lanthanum
oxide, cerium-yttrium oxide, cerium-zirconium-lanthanum oxide,
cerium-zirconium-yttrium oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0.13La.sub.0.04O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide.
[0252] In other embodiments, the cerium oxide particles or cerium
oxide-containing material particles contain Pt, Pd, or a mixture of
Pt and Pd. In other embodiments, the cerium oxide particles or
cerium oxide-containing material particles contain Ru, W, Mo, Nb,
Mn, or Cr. In other embodiments, the cerium oxide particles or
cerium oxide-containing material particles can contain a perovskite
such as FeBaO. In still other embodiments, the cerium oxide
particles or cerium oxide-containing material particles can contain
samarium, zinc, copper, iron, or silver. In some embodiments, the
cerium oxide particles or cerium oxide-containing material
particles can contain any combination of the platinum group metal,
non-platinum group metal, and barium oxide described above. In any
of the disclosed embodiments, the micron-sized cerium
oxide-containing material can comprise cerium oxide,
cerium-zirconium oxide, cerium-lanthanum oxide, cerium-yttrium
oxide, cerium-zirconium-lanthanum oxide, cerium-zirconium-yttrium
oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0.13La.sub.0.04O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide.
[0253] In some embodiments, the NNm.TM. particles make up between
approximately 10% to approximately 40% by weight of the combination
of the NNm.TM. particles, boehmite particles, and cerium oxide
particles. In some embodiments, the NNm.TM. particles make up
between approximately 15% to approximately 30% by weight of the
combination of the NNm.TM. particles, boehmite particles, and
cerium oxide particles. In some embodiments, the NNm.TM. particles
make up between approximately 20% to approximately 25% by weight of
the combination of the NNm.TM. particles, boehmite particles, and
cerium oxide particles. In some embodiments, the NNm.TM. particles
make up about 23% by weight of the combination of the NNm.TM.
particles, boehmite particles, and cerium oxide particles. In some
embodiments, the NNm.TM. particles are a mixture of platinum and
palladium, at a loading of about 0.3-2 wt %, supported on alumina
oxide. In some embodiments, the NNm.TM. particles are a mixture of
platinum and palladium, at a loading of about 0.3-1 wt %, supported
on alumina oxide. In some embodiments, the NNm.TM. particles are a
mixture of platinum and palladium, at a loading of about 0.3-0.5 wt
%, supported on alumina oxide. In one embodiment, the NNm.TM.
particles are a mixture of platinum and palladium, at a loading of
about 0.3 wt %, supported on alumina oxide. Platinum, palladium,
and platinum/palladium mixtures supported on cerium oxide or cerium
oxide-containing material may also be used in the loadings
described previously. In any of the disclosed embodiments, the
micron-sized cerium oxide-containing material can comprise cerium
oxide, cerium-zirconium oxide, cerium-lanthanum oxide,
cerium-yttrium oxide, cerium-zirconium-lanthanum oxide,
cerium-zirconium-yttrium oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0.13La.sub.0.04O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide.
[0254] In some embodiments, the micron-sized porous cerium oxide
particles make up between approximately 50% to approximately 90% by
weight of the combination of the NNm.TM. particles, boehmite
particles, and cerium oxide particles or cerium oxide-containing
material particles. In some embodiments, the micron-sized porous
cerium oxide particles or cerium oxide-containing material
particles make up between approximately 60% to approximately 80% by
weight of the combination of the NNm.TM. particles, boehmite
particles, and cerium oxide particles or cerium oxide-containing
material particles. In some embodiments, the micron-sized porous
cerium oxide particles or cerium oxide-containing material
particles make up between approximately 70% to approximately 75% by
weight of the combination of the NNm.TM. particles, boehmite, and
cerium oxide particles or cerium oxide-containing material
particles. In some embodiments, the micron-sized porous cerium
oxide particles or cerium oxide-containing material particles make
up about 73% by weight of the combination of the NNm.TM. particles,
boehmite, and cerium oxide particles or cerium oxide-containing
material particles. In any of the disclosed embodiments, the
micron-sized cerium oxide-containing material can comprise cerium
oxide, cerium-zirconium oxide, cerium-lanthanum oxide,
cerium-yttrium oxide, cerium-zirconium-lanthanum oxide,
cerium-zirconium-yttrium oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0.13La.sub.0.04O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide.
[0255] In some embodiments, the boehmite particles make up between
approximately 0.5% to approximately 10% by weight of the
combination of the NNm.TM. particles, boehmite particles, and
cerium oxide particles or cerium oxide-containing material
particles. In some embodiments, the boehmite particles make up
between approximately 1% to approximately 7% by weight of the
combination of the NNm.TM. particles, boehmite particles, and
cerium oxide particles or cerium oxide-containing material
particles. In some embodiments, the boehmite particles make up
between approximately 2% to approximately 5% by weight of the
combination of the NNm.TM. particles, boehmite particles, and
cerium oxide particles or cerium oxide-containing material
particles. In some embodiments, the boehmite particles make up
about 4% by weight of the combination of the NNm.TM. particles,
boehmite particles, and cerium oxide particles or cerium
oxide-containing material particles. In any of the disclosed
embodiments, the micron-sized cerium oxide-containing material can
comprise cerium oxide, cerium-zirconium oxide, cerium-lanthanum
oxide, cerium-yttrium oxide, cerium-zirconium-lanthanum oxide,
cerium-zirconium-yttrium oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0.13La.sub.0.04O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide.
[0256] In the NO.sub.x storage washcoat, from 0 to 100% of the
cerium oxide particles or cerium oxide-containing material
particles may be cerium oxide particles or cerium oxide-containing
material particles impregnated with nano-sized BaO particles,
cerium oxide particles or cerium oxide-containing material
particles mixed with micron-sized BaO particles, or both cerium
oxide particles or cerium oxide-containing material particles
impregnated with nano-sized BaO particles and admixed with
micron-sized BaO particles. In some embodiments, from 1 wt %-100 wt
%, from 20 wt %-80 wt %, or from 30 wt %-60 wt % micron-sized BaO
may be used in place of non-BaO-impregnated cerium oxide or
non-BaO-impregnated cerium oxide-containing material. In some
embodiments, a 50:50 mixture of regular HSAS and BaO impregnated
HSAS (impregnated with nano-sized BaO particles), or a 50:50
mixture of HSAS and micron-sized BaO particles, or a mixture of
HSAS impregnated with nano-sized BaO particles and admixed with
micron-sized BaO particles, may be used for this component of the
washcoat. In some embodiments, the cerium oxide particles can
comprise from 5% to 30% nano-BaO-impregnated cerium oxide and from
70% to 95% non-BaO-impregnated cerium oxide. In some embodiments,
the cerium oxide particles can comprise from 5% to 20%
nano-BaO-impregnated cerium oxide and from 80% to 95%
non-BaO-impregnated cerium oxide. In some embodiments, the cerium
oxide particles can comprise from 8% to 16% nano-BaO-impregnated
cerium oxide and from 84% to 92% non-BaO-impregnated cerium oxide.
In one embodiment, 12%, or about 12%, nano-BaO-impregnated cerium
oxide is mixed with 88%, or about 88%, cerium oxide without
impregnated BaO. In one embodiment, 8%, or about 8%,
nano-BaO-impregnated cerium oxide is mixed with 92%, or about 92%,
cerium oxide without impregnated BaO. In any of the disclosed
embodiments, the micron-sized cerium oxide-containing material can
comprise cerium oxide, cerium-zirconium oxide, cerium-lanthanum
oxide, cerium-yttrium oxide, cerium-zirconium-lanthanum oxide,
cerium-zirconium-yttrium oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0.13La.sub.004O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises
[0257] Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide.
Procedure for Preparation of Washcoat Containing Catalysts for
Oxidation Reaction: Two-Layer Washcoat Configurations
[0258] The oxidative nano-on-nano-on-micro catalytically active
material (for example nano-Pd-on-nano-on-micro,
nano-Pt-on-nano-on-micro, or nano-Pt/Pd-on-nano-on-micro) can be
mixed with La-stabilized micron-sized Al.sub.2O.sub.3, boehmite,
and water to form a washcoat slurry. In some instances, the mixture
contains about 50% by weight of the catalytic active material
(nano-on-nano and nano-sized Al.sub.2O.sub.3 without precious
metal), about 47% by weight of the micron-sized Al.sub.2O.sub.3,
and about 3% by weight of the boehmite. In some instances, the
washcoat is adjusted to have a pH of 4 or approximately 4.
Procedure for Preparation of Washcoat Containing Catalysts for
Reduction Reaction and NO.sub.x Storage Material: Two-Layer
Washcoat Configurations
[0259] The reductive nano-on-nano-on-micro catalytically active
material (for example Rh) can be mixed with NO.sub.x trapping
particles, boehmite, and water to form a washcoat slurry. In some
instances, the mixture comprises 15% by weight of the catalytic
active material (for example nano-Rh on nano-cerium oxide on
micro-cerium oxide), 2% by weight of boehmite, and 83% HSAS (for
example HSAS impregnated with barium oxide particles and a mixture
of platinum and palladium). In some instances, the washcoat is
adjusted to have a pH of 4 or approximately 4.
Procedure for Preparation of Washcoat Containing Catalysts for
Oxidation Reaction: Three-Layer Washcoat Configurations
[0260] The oxidative nano-on-nano-on-micro catalytically active
material (for example nano-Pd- or nano-Pt- or
nano-Pt/Pd-on-nano-on-micro) can be mixed with La-stabilized
micron-sized Al.sub.2O.sub.3, boehmite, and water to form a
washcoat slurry. In some instances, the mixture contains about 50%
by weight of the catalytic active material (nano-on-nano and
nano-sized Al.sub.2O.sub.3 without precious metal), about 47% by
weight of the micron-sized Al.sub.2O.sub.3, and about 3% by weight
of the boehmite. In some instances, the washcoat is adjusted to
have a pH of 4 or approximately 4.
Procedure for Preparation of Washcoat Containing Catalysts for
Reduction Reaction: Three-Layer Washcoat Configurations
[0261] The reductive nano-on-nano-on-micro catalytically active
material (for example Rh) can be mixed with La-stabilized
micron-sized Al.sub.2O.sub.3, boehmite, and water to form a
washcoat slurry. In some instances, the mixture contains about 80%
by weight of the catalytic active material (such as nano-on-nano
and nano-sized CeO.sub.2 without precious metal), about 17% by
weight of the micron-sized Al.sub.2O.sub.3, and about 3% by weight
of the boehmite. In some instances, the washcoat is adjusted to
have a pH of 4 or approximately 4.
Procedure for Preparation of Washcoat Containing NO.sub.x Storage
Material: Three-Layer Washcoat Configurations
[0262] The nano-on-nano-on-micro material for temporary storage of
NO.sub.x gases (for example Pt, Pd, or Pt/Pd on nano-sized
Al.sub.2O.sub.3 on micron-sized Al.sub.2O.sub.3) can be mixed with
micron-sized cerium oxide particles or micron-sized cerium
oxide-containing material particles (impregnated with, for example,
barium oxide), boehmite, and water to form a washcoat slurry. In
some instances, the mixture comprises 23% by weight of the NNm
particles, 4% by weight of boehmite, and 73% HSA5. In some
instances, the washcoat is adjusted to have a pH of 4 or
approximately 4.
Coated Substrate with Separate Layers of Reductive Nanoparticles
and NO.sub.x Storage Material
Reductive Nanoparticles and NO.sub.x Storage Material in the Same
Layer
[0263] A coated substrate may include a first layer washcoat
containing oxidative catalytically active nanoparticles, and a
second layer washcoat containing reductive catalytically active
nanoparticles and NO.sub.x storage material. In certain
embodiments, the oxidative catalytically active nanoparticles do
not react with the reductive catalytically active nanoparticles. In
certain embodiments, the reductive catalytically active
nanoparticles do not react with the NO.sub.x storage material. In
certain embodiments, the oxidative catalytically active
nanoparticles do not react with the NO.sub.x storage material.
[0264] The washcoat containing catalysts for oxidation, the
washcoat containing catalysts for reduction, and the NO.sub.x
storage material can be applied to a monolith of a grid array
structure, for example a honeycomb structure. In some instances,
the washcoats can form a layered structure in the channels of the
monolith. In some instances, the washcoat that contains catalysts
for oxidation reactions can be applied first. In some instances,
the washcoat that contains catalysts for reduction reaction and the
NO.sub.x storage material can be applied first. In some instances,
the washcoat that contains catalysts for reduction reaction and the
NO.sub.x storage material can be applied second. In some instances,
the washcoat that contains catalysts for oxidation reactions can be
applied second.
[0265] The following are experimental procedures for making a
coated substrate containing a reductive catalytically active
particles and NO.sub.x storage material in the same washcoat layer.
The reductive catalytic active material is mixed with NO.sub.x
trapping particles, boehmite, and water to form a washcoat slurry.
In some embodiments, the washcoat is adjusted to have a pH of about
4.
[0266] The washcoat contains a catalyst for reduction reactions as
well as NO.sub.x storage material, and can be applied to a monolith
of a grid array structure in a single procedure. The application of
the washcoat onto the monolith can be achieved by dipping the
monolith into a washcoat slurry. After the slurry is dried, the
monolith is baked in an oven at 550.degree. C. for one hour.
Reductive Nanoparticles and NO.sub.x Storage Material in Different
Layers
[0267] A coated substrate may include a first layer washcoat
containing oxidative catalytically active nanoparticles, a second
layer washcoat containing reductive catalytically active
nanoparticles, and a third layer washcoat containing NO.sub.x
storage material. In certain embodiments, the oxidative
catalytically active nanoparticles do not react with the reductive
catalytically active nanoparticles. In certain embodiments, the
reductive catalytically active nanoparticles do not react with the
NO.sub.x storage material. In certain embodiments, the oxidative
catalytically active nanoparticles do not react with the NO.sub.x
storage material.
[0268] The washcoat containing catalysts for oxidation, the
washcoat containing catalysts for reduction, and the washcoat
containing NO.sub.x storage material can be applied to a monolith
of a grid array structure, for example a honeycomb structure. In
some instances, the washcoats can form a layered structure in the
channels of the monolith. In some instances, the washcoat that
contains catalysts for oxidation reactions can be applied first. In
some instances, the washcoat that contains catalysts for reduction
reaction can be applied first. In some instances, the washcoat that
contains NO.sub.x storage material can be applied first. In some
instances, the washcoat that contains catalysts for oxidation
reactions can be applied second. In some instances, the washcoat
that contains catalysts for reduction reactions can be applied
second. In some instances, the washcoat that contains NO.sub.x
storage material can be applied second. In some instances, the
washcoat that contains catalysts for oxidation reactions can be
applied third. In some instances, the washcoat that contains
catalysts for reduction reactions can be applied third. In some
instances, the washcoat that contains NO.sub.x storage material can
be applied third. The application of the washcoat onto the monolith
can be achieved, for example, by dipping the monolith into a
washcoat slurry. After the slurry is dried, the monolith can be
baked in an oven at 550.degree. C. for one hour. Next, the monolith
can be dipped into the second washcoat slurry. After the slurry of
the second dip is dried, the monolith can be baked in the oven
again at 550.degree. C. for one hour. Subsequently, the monolith
can be dipped into the third washcoat slurry. After the slurry of
the third dip is dried, the monolith can be baked in the oven again
at 550.degree. C. for one hour.
[0269] A person having ordinary skill in the art would be able to
use typical methods or procedures to apply the washcoat prepared
according to the procedures described above to make a catalytic
converter, which can be used in various fields, such as for a
catalytic converter for gasoline and/or diesel engines.
Catalytic Converters and Methods of Producing Catalytic
Converters
[0270] In some embodiments, the invention provides for catalytic
converters, which can comprise any of the washcoat layers and
washcoat configurations described herein. The catalytic converters
are useful in a variety of applications, such as in gasoline and
diesel vehicles.
[0271] FIG. 1 illustrates a catalytic converter in accordance with
some embodiments. Catalytically active material is included in a
washcoat composition, which is coated onto a substrate to form a
coated substrate. The coated substrate 114 is enclosed within an
insulating material 112, which in turn is enclosed within a
metallic container 110 (of, for example, stainless steel). A heat
shield 108 and a gas sensor (for example, an oxygen sensor) 106 are
depicted. The catalytic converter may be affixed to the exhaust
system of the vehicle through flanges 104 and 118. The exhaust gas,
which includes the raw emissions of hydrocarbons, carbon monoxide,
and nitrogen oxides, enters the catalytic converter at 102. As the
raw emissions pass through the catalytic converter, they react with
the catalytically active material on the coated substrate,
resulting in tailpipe emissions of water, carbon dioxide, and
nitrogen exiting at 120. FIG. 1A is a magnified view of a section
of the coated substrate 114, which shows the honeycomb structure of
the coated substrate. The coated substrates, as described below,
may be incorporated into a catalytic converter for use in a vehicle
emissions control system.
[0272] FIG. 2 is a flow chart illustrating an LNT system
preparation method 200 in accordance with embodiments of the
present disclosure. The LNT system includes oxidative catalytically
active particles and reductive catalytically active particles in
separate washcoat layers on a substrate. The LNT system embodies
the reductive catalytically active particles and the NO.sub.x
storage material in a single washcoat layer on the substrate.
[0273] The LNT system preparation method 200 can start from Step
202. At Step 204, a catalyst for oxidation reaction is prepared. At
Step 206, a first washcoat containing the catalyst for oxidation
reaction is prepared. At Step 208, a catalyst for reduction
reaction is prepared. At step 210, cerium oxide particles or cerium
oxide-containing material particles impregnated with NO.sub.x
storing materials are prepared. At Step 212, a second washcoat
containing the catalyst for reduction reaction and the impregnated
cerium oxide particles or cerium oxide-containing material
particles for NO.sub.x storage are prepared. At Step 214, either
the first washcoat or the second washcoat is applied to a
substrate. At Step 216, the substrate is dried. At Step 218, the
washcoat-covered substrate is baked in an oven allowing the
formation of the oxide-oxide bonds, resulting in immobilized
particles. At Step 220, the other washcoat is applied on the
substrate. At Step 222, the substrate is dried. At Step 224, the
washcoat-covered substrate with oxidative catalytically active
particles and reductive catalytically active particles contained in
separate layers, and reductive catalytically active particles and
NO.sub.x storage material contained in the same layer, is baked in
an oven allowing the formation of the oxide-oxide bonds. The method
200 ends at Step 226. The oxide-oxide bonds formed during the
baking process firmly retain the nanoparticles, so that the chances
for the oxidative nanoparticles and/or the reductive nanoparticles
to move at high temperature and to encounter and react with each
other are avoided. In any of the disclosed embodiments, the
micron-sized cerium oxide-containing material can comprise cerium
oxide, cerium-zirconium oxide, cerium-lanthanum oxide,
cerium-yttrium oxide, cerium-zirconium-lanthanum oxide,
cerium-zirconium-yttrium oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0.13La.sub.004O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide.
[0274] FIG. 3 is a flow chart illustrating an LNT system
preparation method 300 in accordance with embodiments of the
present disclosure. The LNT system includes oxidative catalytically
active particles and reductive catalytically active particles in
separate washcoat layers on a substrate. The LNT system embodies
the reductive catalytically active particles and the NO.sub.x
storage material in separate washcoat layers on the substrate.
[0275] The LNT system preparation method 300 can start from Step
302. At Step 304, a catalyst for oxidation reaction is prepared. At
Step 306, a first washcoat containing the catalyst for oxidation
reaction is prepared. At Step 308, a catalyst for reduction
reaction is prepared. At Step 310, a second washcoat containing the
catalyst for reduction reaction is prepared. At step 312, cerium
oxide particles or cerium oxide-containing material particles
impregnated with NO.sub.x storing materials are prepared. At Step
314, a third washcoat containing the cerium oxide particles or
cerium oxide-containing material particles impregnated with
NO.sub.x storing materials is prepared. At Step 316, either the
first washcoat, the second, or the third washcoat is applied to a
substrate. At Step 318, the substrate is dried. At Step 320, the
washcoat-covered substrate is baked in an oven allowing the
formation of the oxide-oxide bonds, resulting in immobilized
particles. At Step 322, one of the remaining two washcoats is
applied on the substrate. At Step 324, the substrate is dried. At
Step 326, the washcoat-covered substrate is baked in an oven
allowing the formation of the oxide-oxide bonds. At Step 328, the
final remaining washcoat is applied on the substrate. At Step 330,
the substrate is dried. At Step 332, the washcoat-covered substrate
with oxidative catalytically active particles, reductive
catalytically active particles, and cerium oxide particles or
cerium oxide-containing material particles impregnated with
NO.sub.x storing materials contained in separate layers is baked in
an oven allowing the formation of the oxide-oxide bonds. The method
300 ends at Step 334. The oxide-oxide bonds formed during the
baking process firmly retain the nanoparticles, so that the chances
for the oxidative nanoparticles and/or the reductive nanoparticles
to move at high temperature and to encounter and react with each
other are avoided. In any of the disclosed embodiments, the
micron-sized cerium oxide-containing material can comprise cerium
oxide, cerium-zirconium oxide, cerium-lanthanum oxide,
cerium-yttrium oxide, cerium-zirconium-lanthanum oxide,
cerium-zirconium-yttrium oxide, cerium-lanthanum-yttrium oxide, or
cerium-zirconium-lanthanum-yttrium oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.83Zr.sub.0.13La.sub.0.04O. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises a material that comprises about 86% cerium oxide, 10%
zirconium oxide, and 4% lanthanum oxide. In some preferred
embodiments, the micron-sized cerium oxide-containing material
comprises Ce.sub.0.35Zr.sub.0.62La.sub.0.044Y.sub.0.06O. In some
preferred embodiments, the micron-sized cerium oxide-containing
material comprises a material that comprises about 40% cerium
oxide, 50% zirconium oxide, 5% lanthanum oxide, and 5% yttrium
oxide.
Exhaust Systems, Vehicles, and Emissions Performance
[0276] LNTs have utility in a number of fields including the
treatment of exhaust gas streams from internal combustion engines
such as automobile, truck, and other gasoline-fueled engines.
Emission standards for unburned hydrocarbons, carbon monoxide and
nitrogen oxide contaminants have been set by various governments
and must be met by older, as well as new, vehicles. In order to
meet such standards, catalytic converters containing an LNT system
are located in the exhaust gas line of internal combustion engines.
LNT systems first store, then reduce, nitrogen oxides to
nitrogen.
[0277] In some embodiments, a coated substrate as disclosed herein
is housed within a catalytic converter in a position configured to
receive exhaust gas from an internal combustion engine, such as in
an exhaust system of an internal combustion engine. The catalytic
converter can be used with the exhaust from a gasoline engine. The
catalytic converter can be installed on a vehicle containing a
gasoline engine. The catalytic converter can be used with the
exhaust from a diesel engine. The catalytic converter can be
installed on a vehicle containing a diesel engine.
[0278] The coated substrate is placed into a housing, such as that
shown in FIG. 1, which can in turn be placed into an exhaust system
(also referred to as an exhaust treatment system) of an internal
combustion engine. The internal combustion engine can be a gasoline
engine or a diesel engine, such as a light-duty engine, such as the
engine of a light-duty vehicle. The exhaust system of the internal
combustion engine receives exhaust gases from the engine, typically
into an exhaust manifold, and delivers the exhaust gases to an
exhaust treatment system. The exhaust system can also include other
components, such as oxygen sensors, HEGO (heated exhaust gas
oxygen) sensors, UEGO (universal exhaust gas oxygen) sensors,
sensors for other gases, and temperature sensors. The exhaust
system can also include a controller such as an engine control unit
(ECU), a microprocessor, or an engine management computer, which
can adjust various parameters in the vehicle (fuel flow rate,
fuel/air ratio, fuel injection, engine timing, valve timing, etc.)
in order to optimize the components of the exhaust gases that reach
the exhaust treatment system, so as to manage the emissions
released into the environment.
[0279] "Treating" an exhaust gas, such as the exhaust gas from a
gasoline or diesel engine, refers to having the exhaust gas proceed
through an exhaust system (exhaust treatment system) prior to
release into the environment.
[0280] When used in a catalytic converter, the substrates coated
with the washcoat formulations including nano-on-nano-on-micro
particles disclosed herein provide a significant improvement over
other catalytic converters. The coated substrates may exhibit
performance in converting hydrocarbons, carbon monoxide, and
nitrogen oxides that is comparable to or better than present
commercial coated substrates using wet chemistry techniques with
the same or less loading of PGM. The coated substrates, catalytic
converters, and exhaust treatment systems described herein are
useful for any vehicle employing an LNT or NSC system.
[0281] Emissions limits for Europe are summarized at the URL
europa.eu/legislation_summaries/environment/air_pollution/128186_en.htm.
The Euro 6 emissions standards, scheduled for implementation as of
September 2014, specify a limit of 500 mg/km of CO emissions, 80
mg/km of NO.sub.x emissions, and 170 mg/km of HC
(hydrocarbon)+NO.sub.x emissions. The disclosed catalytic converter
substrates can be used in an emission system to meet or exceed
these standards.
[0282] In some embodiments, a catalytic converter made with a
coated substrate of the invention, loaded with 4.0 g/L of PGM or
less displays a carbon monoxide light-off temperature at least
5.degree. C. lower than a catalytic converter made with wet
chemistry methods and having the same or similar PGM loading. In
some embodiments, a catalytic converter made with a coated
substrate of the invention, loaded with 4.0 g/L of PGM or less,
displays a carbon monoxide light-off temperature at least
10.degree. C. lower than a catalytic converter made with wet
chemistry methods and having the same or similar PGM loading. In
some embodiments, a catalytic converter made with a coated
substrate of the invention, loaded with 4.0 g/L of PGM or less,
displays a carbon monoxide light-off temperature at least
15.degree. C. lower than a catalytic converter made with wet
chemistry methods and having the same or similar PGM loading. In
some embodiments, the catalytic converter made with a coated
substrate of the invention demonstrates any of the foregoing
performance standards after about 50,000 km, about 50,000 miles,
about 75,000 km, about 75,000 miles, about 100,000 km, about
100,000 miles, about 125,000 km, about 125,000 miles, about 150,000
km, or about 150,000 miles of operation (for both the catalytic
converter made with a coated substrate of the invention and the
comparative catalytic converter).
[0283] In some embodiments, a catalytic converter made with a
coated substrate of the invention, loaded with 4.0 g/L of PGM or
less, displays a hydrocarbon light-off temperature at least
5.degree. C. lower than a catalytic converter made with wet
chemistry methods and having the same or similar PGM loading. In
some embodiments, a catalytic converter made with a coated
substrate of the invention, loaded with 4.0 g/L of PGM or less,
displays a hydrocarbon light-off temperature at least 10.degree. C.
lower than a catalytic converter made with wet chemistry methods
and having the same or similar PGM loading. In some embodiments, a
catalytic converter made with a coated substrate of the invention,
loaded with 4.0 g/L of PGM or less, displays a hydrocarbon
light-off temperature at least 15.degree. C. lower than a catalytic
converter made with wet chemistry methods and having the same or
similar PGM loading. In some embodiments, the catalytic converter
made with a coated substrate of the invention demonstrates any of
the foregoing performance standards after about 50,000 km, about
50,000 miles, about 75,000 km, about 75,000 miles, about 100,000
km, about 100,000 miles, about 125,000 km, about 125,000 miles,
about 150,000 km, or about 150,000 miles of operation (for both the
catalytic converter made with a coated substrate of the invention
and the comparative catalytic converter).
[0284] In some embodiments, a catalytic converter made with a
coated substrate of the invention, loaded with 4.0 g/L of PGM or
less, displays a nitrogen oxide light-off temperature at least
5.degree. C. lower than a catalytic converter made with wet
chemistry methods and having the same or similar PGM loading. In
some embodiments, a catalytic converter made with a coated
substrate of the invention, loaded with 4.0 g/L of PGM or less,
displays a nitrogen oxide light-off temperature at least 10.degree.
C. lower than a catalytic converter made with wet chemistry methods
and having the same or similar PGM loading. In some embodiments, a
catalytic converter made with a coated substrate of the invention,
loaded with 4.0 g/L of PGM or less, displays a nitrogen oxide
light-off temperature at least 15.degree. C. lower than a catalytic
converter made with wet chemistry methods and having the same or
similar PGM loading. In some embodiments, the catalytic converter
made with a coated substrate of the invention demonstrates any of
the foregoing performance standards after about 50,000 km, about
50,000 miles, about 75,000 km, about 75,000 miles, about 100,000
km, about 100,000 miles, about 125,000 km, about 125,000 miles,
about 150,000 km, or about 150,000 miles of operation (for both the
catalytic converter made with a coated substrate of the invention
and the comparative catalytic converter).
[0285] In some embodiments, a catalytic converter made with a
coated substrate of the invention, loaded with 3.0 g/L of PGM or
less, displays a carbon monoxide light-off temperature at least
5.degree. C. lower than a catalytic converter made with wet
chemistry methods and having the same or similar PGM loading. In
some embodiments, a catalytic converter made with a coated
substrate of the invention, loaded with 3.0 g/L of PGM or less,
displays a carbon monoxide light-off temperature at least
10.degree. C. lower than a catalytic converter made with wet
chemistry methods and having the same or similar PGM loading. In
some embodiments, a catalytic converter made with a coated
substrate of the invention, loaded with 3.0 g/L of PGM or less,
displays a carbon monoxide light-off temperature at least
15.degree. C. lower than a catalytic converter made with wet
chemistry methods and having the same or similar PGM loading. In
some embodiments, the catalytic converter made with a coated
substrate of the invention demonstrates any of the foregoing
performance standards after about 50,000 km, about 50,000 miles,
about 75,000 km, about 75,000 miles, about 100,000 km, about
100,000 miles, about 125,000 km, about 125,000 miles, about 150,000
km, or about 150,000 miles of operation (for both the catalytic
converter made with a coated substrate of the invention and the
comparative catalytic converter).
[0286] In some embodiments, a catalytic converter made with a
coated substrate of the invention, loaded with 3.0 g/L of PGM or
less, displays a hydrocarbon light-off temperature at least
5.degree. C. lower than a catalytic converter made with wet
chemistry methods and having the same or similar PGM loading. In
some embodiments, a catalytic converter made with a coated
substrate of the invention, loaded with 3.0 g/L of PGM or less,
displays a hydrocarbon light-off temperature at least 10.degree. C.
lower than a catalytic converter made with wet chemistry methods
and having the same or similar PGM loading. In some embodiments, a
catalytic converter made with a coated substrate of the invention,
loaded with 3.0 g/L of PGM or less, displays a hydrocarbon
light-off temperature at least 15.degree. C. lower than a catalytic
converter made with wet chemistry methods and having the same or
similar PGM loading. In some embodiments, the catalytic converter
made with a coated substrate of the invention demonstrates any of
the foregoing performance standards after about 50,000 km, about
50,000 miles, about 75,000 km, about 75,000 miles, about 100,000
km, about 100,000 miles, about 125,000 km, about 125,000 miles,
about 150,000 km, or about 150,000 miles of operation (for both the
catalytic converter made with a coated substrate of the invention
and the comparative catalytic converter).
[0287] In some embodiments, a catalytic converter made with a
coated substrate of the invention, loaded with 3.0 g/L of PGM or
less, displays a nitrogen oxide light-off temperature at least
5.degree. C. lower than a catalytic converter made with wet
chemistry methods and having the same or similar PGM loading. In
some embodiments, a catalytic converter made with a coated
substrate of the invention, loaded with 3.0 g/L of PGM or less,
displays a nitrogen oxide light-off temperature at least 10.degree.
C. lower than a catalytic converter made with wet chemistry methods
and having the same or similar PGM loading. In some embodiments, a
catalytic converter made with a coated substrate of the invention,
loaded with 3.0 g/L of PGM or less, displays a nitrogen oxide
light-off temperature at least 15.degree. C. lower than a catalytic
converter made with wet chemistry methods and having the same or
similar PGM loading. In some embodiments, the catalytic converter
made with a coated substrate of the invention demonstrates any of
the foregoing performance standards after about 50,000 km, about
50,000 miles, about 75,000 km, about 75,000 miles, about 100,000
km, about 100,000 miles, about 125,000 km, about 125,000 miles,
about 150,000 km, or about 150,000 miles of operation (for both the
catalytic converter made with a coated substrate of the invention
and the comparative catalytic converter).
[0288] In some embodiments, a catalytic converter made with a
coated substrate of the invention displays a carbon monoxide
light-off temperature within .+-.2.degree. C. of the carbon
monoxide light-off temperature of a catalytic converter made with
wet chemistry methods, while the catalytic converter made with a
coated substrate employing about 30 to 40% less catalyst than the
catalytic converter made with wet chemistry methods. In some
embodiments, the catalytic converter made with a coated substrate
of the invention demonstrates this performance after about 50,000
km, about 50,000 miles, about 75,000 km, about 75,000 miles, about
100,000 km, about 100,000 miles, about 125,000 km, about 125,000
miles, about 150,000 km, or about 150,000 miles of operation (for
both the catalytic converter made with a coated substrate of the
invention and the comparative catalytic converter).
[0289] In some embodiments, a catalytic converter made with a
coated substrate of the invention displays a carbon monoxide
light-off temperature within .+-.1.degree. C. of the carbon
monoxide light-off temperature of a catalytic converter made with
wet chemistry methods, while the catalytic converter made with a
coated substrate employing about 30 to 40% less catalyst than the
catalytic converter made with wet chemistry methods. In some
embodiments, the catalytic converter made with a coated substrate
of the invention demonstrates this performance after about 50,000
km, about 50,000 miles, about 75,000 km, about 75,000 miles, about
100,000 km, about 100,000 miles, about 125,000 km, about 125,000
miles, about 150,000 km, or about 150,000 miles of operation (for
both the catalytic converter made with a coated substrate of the
invention and the comparative catalytic converter).
[0290] In some embodiments, a catalytic converter made with a
coated substrate of the invention displays a carbon monoxide
light-off temperature within .+-.2.degree. C. of the hydrocarbon
light-off temperature of a catalytic converter made with wet
chemistry methods, while the catalytic converter made with a coated
substrate employing about 30 to 40% less catalyst than the
catalytic converter made with wet chemistry methods. In some
embodiments, the catalytic converter made with a coated substrate
of the invention demonstrates this performance after about 50,000
km, about 50,000 miles, about 75,000 km, about 75,000 miles, about
100,000 km, about 100,000 miles, about 125,000 km, about 125,000
miles, about 150,000 km, or about 150,000 miles of operation (for
both the catalytic converter made with a coated substrate of the
invention and the comparative catalytic converter).
[0291] In some embodiments, a catalytic converter made with a
coated substrate of the invention displays a carbon monoxide
light-off temperature within .+-.1.degree. C. of the hydrocarbon
light-off temperature of a catalytic converter made with wet
chemistry methods, while the catalytic converter made with a coated
substrate employing about 30 to 40% less catalyst than the
catalytic converter made with wet chemistry methods. In some
embodiments, the catalytic converter made with a coated substrate
of the invention demonstrates this performance after about 50,000
km, about 50,000 miles, about 75,000 km, about 75,000 miles, about
100,000 km, about 100,000 miles, about 125,000 km, about 125,000
miles, about 150,000 km, or about 150,000 miles of operation (for
both the catalytic converter made with a coated substrate of the
invention and the comparative catalytic converter).
[0292] In some embodiments, a catalytic converter made with a
coated substrate of the invention displays a carbon monoxide
light-off temperature within .+-.2.degree. C. of the nitrogen oxide
light-off temperature of a catalytic converter made with wet
chemistry methods, while the catalytic converter made with a coated
substrate employing about 30 to 40% less catalyst than the
catalytic converter made with wet chemistry methods. In some
embodiments, the catalytic converter made with a coated substrate
of the invention demonstrates this performance after about 50,000
km, about 50,000 miles, about 75,000 km, about 75,000 miles, about
100,000 km, about 100,000 miles, about 125,000 km, about 125,000
miles, about 150,000 km, or about 150,000 miles of operation (for
both the catalytic converter made with a coated substrate of the
invention and the comparative catalytic converter).
[0293] In some embodiments, a catalytic converter made with a
coated substrate of the invention displays a carbon monoxide
light-off temperature within .+-.4.degree. C. of the nitrogen oxide
light-off temperature of a catalytic converter made with wet
chemistry methods, while the catalytic converter made with a coated
substrate employing about 30 to 40% less catalyst than the
catalytic converter made with wet chemistry methods. In some
embodiments, the catalytic converter made with a coated substrate
of the invention demonstrates this performance after about 50,000
km, about 50,000 miles, about 75,000 km, about 75,000 miles, about
100,000 km, about 100,000 miles, about 125,000 km, about 125,000
miles, about 150,000 km, or about 150,000 miles of operation (for
both the catalytic converter made with a coated substrate of the
invention and the comparative catalytic converter).
[0294] In some embodiments, a catalytic converter made with a
coated substrate of the invention employed on a gasoline engine or
gasoline vehicle complies with United States EPA emissions
requirements, while using at least about 30% less, up to about 30%
less, at least about 40% less, up to about 40% less, at least about
50% less, or up to about 50% less, platinum group metal or platinum
group metal loading, as compared to a catalytic converter made with
wet chemistry methods which complies with the same standard. In
some embodiments, the coated substrate is used in a catalytic
converter to meet or exceed these standards. The emissions
requirements can be intermediate life requirements or full life
requirements. The requirements can be TLEV requirements, LEV
requirements, or ULEV requirements. In some embodiments, the
catalytic converter made with a coated substrate of the invention
demonstrates any of the foregoing performance standards after about
50,000 km, about 50,000 miles, about 75,000 km, about 75,000 miles,
about 100,000 km, about 100,000 miles, about 125,000 km, about
125,000 miles, about 150,000 km, or about 150,000 miles of
operation (for both the catalytic converter made with a coated
substrate of the invention and the comparative catalytic
converter).
[0295] In some embodiments, a catalytic converter made with a
coated substrate of the invention employed on a gasoline engine or
gasoline vehicle complies with EPA TLEV/LEV intermediate life
requirements. In some embodiments, a catalytic converter made with
a coated substrate of the invention employed on a gasoline engine
or gasoline vehicle complies with EPA TLEV/LEV full life
requirements. In some embodiments, a catalytic converter made with
a coated substrate of the invention employed on a gasoline engine
or gasoline vehicle complies with EPA ULEV intermediate life
requirements. In some embodiments, a catalytic converter made with
a coated substrate of the invention employed on a gasoline engine
or gasoline vehicle complies with EPA ULEV full life requirements.
In some embodiments, the coated substrate is used in a catalytic
converter to meet or exceed these standards. In some embodiments,
the catalytic converter made with a coated substrate of the
invention demonstrates any of the foregoing performance standards
after about 50,000 km, about 50,000 miles, about 75,000 km, about
75,000 miles, about 100,000 km, about 100,000 miles, about 125,000
km, about 125,000 miles, about 150,000 km, or about 150,000 miles
of operation.
[0296] In some embodiments, a catalytic converter made with a
coated substrate of the invention employed on a gasoline engine or
gasoline vehicle complies with EPA TLEV/LEV intermediate life
requirements, while using at least about 30% less, up to about 30%
less, at least about 40% less, up to about 40% less, at least about
50% less, or up to about 50% less, platinum group metal or platinum
group metal loading, as compared to a catalytic converter made with
wet chemistry methods which complies with that standard. In some
embodiments, a catalytic converter made with a coated substrate of
the invention employed on a gasoline engine or gasoline vehicle
complies with EPA TLEV/LEV full life requirements, while using at
least about 30% less, up to about 30% less, at least about 40%
less, up to about 40% less, at least about 50% less, or up to about
50% less, platinum group metal or platinum group metal loading, as
compared to a catalytic converter made with wet chemistry methods
which complies with that standard. In some embodiments, a catalytic
converter made with a coated substrate of the invention employed on
a gasoline engine or gasoline vehicle complies with EPA ULEV
intermediate life requirements, while using at least about 30%
less, up to about 30% less, at least about 40% less, up to about
40% less, at least about 50% less, or up to about 50% less,
platinum group metal or platinum group metal loading, as compared
to a catalytic converter made with wet chemistry methods which
complies with that standard. In some embodiments, a catalytic
converter made with a coated substrate of the invention employed on
a gasoline engine or gasoline vehicle complies with EPA ULEV full
life requirements, while using at least about 30% less, up to about
30% less, at least about 40% less, up to about 40% less, at least
about 50% less, or up to about 50% less, platinum group metal or
platinum group metal loading, as compared to a catalytic converter
made with wet chemistry methods which complies with that standard.
In some embodiments, a catalytic converter made with a coated
substrate of the invention employed on a gasoline engine or
gasoline vehicle complies with EPA SULEV intermediate life
requirements, while using at least about 30% less, up to about 30%
less, at least about 40% less, up to about 40% less, at least about
50% less, or up to about 50% less, platinum group metal or platinum
group metal loading, as compared to a catalytic converter made with
wet chemistry methods which complies with that standard. In some
embodiments, a catalytic converter made with a coated substrate of
the invention employed on a gasoline engine or gasoline vehicle
complies with EPA SULEV full life requirements, while using at
least about 30% less, up to about 30% less, at least about 40%
less, up to about 40% less, at least about 50% less, or up to about
50% less, platinum group metal or platinum group metal loading, as
compared to a catalytic converter made with wet chemistry methods
which complies with that standard. In some embodiments, the coated
substrate is used in a catalytic converter to meet or exceed these
standards. In some embodiments, the catalytic converter made with a
coated substrate of the invention demonstrates any of the foregoing
performance standards after about 50,000 km, about 50,000 miles,
about 75,000 km, about 75,000 miles, about 100,000 km, about
100,000 miles, about 125,000 km, about 125,000 miles, about 150,000
km, or about 150,000 miles of operation (for both the catalytic
converter made with a coated substrate of the invention and the
comparative catalytic converter). In some embodiments, the
requirements above are those for light duty vehicles. In some
embodiments, the requirements above are those for light duty
trucks. In some embodiments, the requirements above are those for
medium duty vehicles.
[0297] In some embodiments, a catalytic converter made with a
coated substrate of the invention employed on a gasoline engine or
gasoline vehicle complies with Euro 6 requirements. In some
embodiments, the coated substrate is used in a catalytic converter
to meet or exceed these standards. In some embodiments, the
catalytic converter made with a coated substrate of the invention
demonstrates any of the foregoing performance standards after about
50,000 km, about 50,000 miles, about 75,000 km, about 75,000 miles,
about 100,000 km, about 100,000 miles, about 125,000 km, about
125,000 miles, about 150,000 km, or about 150,000 miles of
operation.
[0298] In some embodiments, a catalytic converter made with a
coated substrate of the invention employed on a gasoline engine or
gasoline vehicle complies with Euro 6 requirements, while using at
least about 30% less, up to about 30% less, at least about 40%
less, up to about 40% less, at least about 50% less, or up to about
50% less, platinum group metal or platinum group metal loading, as
compared to a catalytic converter made with wet chemistry methods
which complies with Euro 6 requirements. In some embodiments, the
coated substrate is used in a catalytic converter to meet or exceed
these standards. In some embodiments, the catalytic converter made
with a coated substrate of the invention demonstrates any of the
foregoing performance standards after about 50,000 km, about 50,000
miles, about 75,000 km, about 75,000 miles, about 100,000 km, about
100,000 miles, about 125,000 km, about 125,000 miles, about 150,000
km, or about 150,000 miles of operation (for both the catalytic
converter made with a coated substrate of the invention and the
comparative catalytic converter).
[0299] In some embodiments, a catalytic converter made with a
coated substrate of the invention employed on a gasoline engine or
gasoline vehicle displays carbon monoxide emissions of 4200 mg/mile
or less. In some embodiments, a catalytic converter made with a
coated substrate of the invention and employed on a gasoline engine
or gasoline vehicle displays carbon monoxide emissions of 3400
mg/mile or less. In some embodiments, a catalytic converter made
with a coated substrate of the invention and employed on a gasoline
engine or gasoline vehicle displays carbon monoxide emissions of
2100 mg/mile or less. In another embodiment, a catalytic converter
made with a coated substrate of the invention and employed on a
gasoline engine or gasoline vehicle displays carbon monoxide
emissions of 1700 mg/mile or less. In some embodiments, the coated
substrate is used in a catalytic converter to meet or exceed these
standards. In some embodiments, the catalytic converter made with a
coated substrate of the invention demonstrates any of the foregoing
performance standards after about 50,000 km, about 50,000 miles,
about 75,000 km, about 75,000 miles, about 100,000 km, about
100,000 miles, about 125,000 km, about 125,000 miles, about 150,000
km, or about 150,000 miles of operation.
[0300] In some embodiments, a catalytic converter made with a
coated substrate of the invention and employed on a gasoline engine
or gasoline vehicle displays carbon monoxide emissions of 500 mg/km
or less. In some embodiments, a catalytic converter made with a
coated substrate of the invention and employed on a gasoline engine
or gasoline vehicle displays carbon monoxide emissions of 375 mg/km
or less. In some embodiments, a catalytic converter made with a
coated substrate of the invention and employed on a gasoline engine
or gasoline vehicle displays carbon monoxide emissions of 250 mg/km
or less. In some embodiments, the coated substrate is used in a
catalytic converter to meet or exceed these standards. In some
embodiments, the catalytic converter made with a coated substrate
of the invention demonstrates any of the foregoing performance
standards after about 50,000 km, about 50,000 miles, about 75,000
km, about 75,000 miles, about 100,000 km, about 100,000 miles,
about 125,000 km, about 125,000 miles, about 150,000 km, or about
150,000 miles of operation.
[0301] In some embodiments, a catalytic converter made with a
coated substrate of the invention and employed on a gasoline engine
or gasoline vehicle displays NO.sub.x emissions of 180 mg/km or
less. In some embodiments, a catalytic converter made with a coated
substrate of the invention and employed on a gasoline engine or
gasoline vehicle displays NO.sub.x emissions of 80 mg/km or less.
In some embodiments, a catalytic converter made with a coated
substrate of the invention and employed on a gasoline engine or
gasoline vehicle displays NO.sub.x emissions of 40 mg/km or less.
In some embodiments, the coated substrate is used in a catalytic
converter to meet or exceed these standards. In some embodiments,
the catalytic converter made with a coated substrate of the
invention demonstrates any of the foregoing performance standards
after about 50,000 km, about 50,000 miles, about 75,000 km, about
75,000 miles, about 100,000 km, about 100,000 miles, about 125,000
km, about 125,000 miles, about 150,000 km, or about 150,000 miles
of operation.
[0302] In some embodiments, a catalytic converter made with a
coated substrate of the invention and employed on a gasoline engine
or gasoline vehicle displays NO.sub.x plus HC emissions of 230
mg/km or less. In some embodiments, a catalytic converter made with
a coated substrate of the invention and employed on a gasoline
engine or gasoline vehicle displays NO.sub.x plus HC emissions of
170 mg/km or less. In some embodiments, a catalytic converter made
with a coated substrate of the invention and employed on a gasoline
engine or gasoline vehicle displays NO.sub.x plus HC emissions of
85 mg/km or less. In some embodiments, the coated substrate is used
in a catalytic converter to meet or exceed these standards. In some
embodiments, the catalytic converter made with a coated substrate
of the invention demonstrates any of the foregoing performance
standards after about 50,000 km, about 50,000 miles, about 75,000
km, about 75,000 miles, about 100,000 km, about 100,000 miles,
about 125,000 km, about 125,000 miles, about 150,000 km, or about
150,000 miles of operation.
[0303] In some embodiments, a catalytic converter made with a
coated substrate and employed on a gasoline engine or gasoline
vehicle displays carbon monoxide emissions of 500 mg/km or less,
while using at least about 30% less, up to about 30% less, at least
about 40% less, up to about 40% less, at least about 50% less, or
up to about 50% less, platinum group metal or platinum group metal
loading, as compared to a catalytic converter made with wet
chemistry methods which displays the same or similar emissions. In
some embodiments, a catalytic converter made with a coated
substrate of the invention and employed on a gasoline engine or
gasoline vehicle displays carbon monoxide emissions of 375 mg/km or
less, while using at least about 30% less, up to about 30% less, at
least about 40% less, up to about 40% less, at least about 50%
less, or up to about 50% less, platinum group metal or platinum
group metal loading, as compared to a catalytic converter made with
wet chemistry methods which displays the same or similar emissions.
In some embodiments, a catalytic converter made with a coated
substrate of the invention and employed on a gasoline engine or
gasoline vehicle displays carbon monoxide emissions of 250 mg/km or
less, while using at least about 30% less, up to about 30% less, at
least about 40% less, up to about 40% less, at least about 50%
less, or up to about 50% less, platinum group metal or platinum
group metal loading, as compared to a catalytic converter made with
wet chemistry methods which displays the same or similar emissions.
In some embodiments, the coated substrate is used in a catalytic
converter to meet or exceed these standards. In some embodiments,
the catalytic converter made with a coated substrate of the
invention demonstrates any of the foregoing performance standards
after about 50,000 km, about 50,000 miles, about 75,000 km, about
75,000 miles, about 100,000 km, about 100,000 miles, about 125,000
km, about 125,000 miles, about 150,000 km, or about 150,000 miles
of operation (for both the catalytic converter made with a coated
substrate of the invention and the comparative catalytic
converter).
[0304] In some embodiments, a catalytic converter made with a
coated substrate of the invention and employed on a gasoline engine
or gasoline vehicle displays NO.sub.x emissions of 180 mg/km or
less, while using at least about 30% less, up to about 30% less, at
least about 40% less, up to about 40% less, at least about 50%
less, or up to about 50% less, platinum group metal or platinum
group metal loading, as compared to a catalytic converter made with
wet chemistry methods which displays the same or similar emissions.
In some embodiments, a catalytic converter made with a coated
substrate of the invention and employed on a gasoline engine or
gasoline vehicle displays NO.sub.x emissions of 80 mg/km or less,
while using at least about 30% less, up to about 30% less, at least
about 40% less, up to about 40% less, at least about 50% less, or
up to about 50% less, platinum group metal or platinum group metal
loading, as compared to a catalytic converter made with wet
chemistry methods which displays the same or similar emissions. In
some embodiments, a catalytic converter made with a coated
substrate of the invention and employed on a gasoline engine or
gasoline vehicle displays NO.sub.x emissions of 40 mg/km or less,
while using at least about 30% less, up to about 30% less, at least
about 40% less, up to about 40% less, at least about 50% less, or
up to about 50% less, platinum group metal or platinum group metal
loading, as compared to a catalytic converter made with wet
chemistry methods which displays the same or similar emissions. In
some embodiments, the coated substrate is used in a catalytic
converter to meet or exceed these standards. In some embodiments,
the catalytic converter made with a coated substrate of the
invention demonstrates any of the foregoing performance standards
after about 50,000 km, about 50,000 miles, about 75,000 km, about
75,000 miles, about 100,000 km, about 100,000 miles, about 125,000
km, about 125,000 miles, about 150,000 km, or about 150,000 miles
of operation (for both the catalytic converter made with a coated
substrate of the invention and the comparative catalytic
converter).
[0305] In some embodiments, a catalytic converter made with a
coated substrate of the invention and employed on a gasoline engine
or gasoline vehicle displays NO.sub.x plus HC emissions of 230
mg/km or less, while using at least about 30% less, up to about 30%
less, at least about 40% less, up to about 40% less, at least about
50% less, or up to about 50% less, platinum group metal or platinum
group metal loading, as compared to a catalytic converter made with
wet chemistry methods which displays the same or similar emissions.
In some embodiments, a catalytic converter made with a coated
substrate of the invention and employed on a gasoline engine or
gasoline vehicle displays NO.sub.x plus HC emissions of 170 mg/km
or less, while using at least about 30% less, up to about 30% less,
at least about 40% less, up to about 40% less, at least about 50%
less, or up to about 50% less, platinum group metal or platinum
group metal loading, as compared to a catalytic converter made with
wet chemistry methods which displays the same or similar emissions.
In some embodiments, a catalytic converter made with a coated
substrate of the invention and employed on a gasoline engine or
gasoline vehicle displays NO.sub.x plus HC emissions of 85 mg/km or
less, while using at least about 30% less, up to about 30% less, at
least about 40% less, up to about 40% less, at least about 50%
less, or up to about 50% less, platinum group metal or platinum
group metal loading, as compared to a catalytic converter made with
wet chemistry methods which displays the same or similar emissions.
In some embodiments, the coated substrate is used in a catalytic
converter to meet or exceed these standards. In some embodiments,
the catalytic converter made with a coated substrate of the
invention demonstrates any of the foregoing performance standards
after about 50,000 km, about 50,000 miles, about 75,000 km, about
75,000 miles, about 100,000 km, about 100,000 miles, about 125,000
km, about 125,000 miles, about 150,000 km, or about 150,000 miles
of operation (for both the catalytic converter made with a coated
substrate of the invention and the comparative catalytic
converter).
[0306] In some embodiments, for the above-described comparisons,
the thrifting (reduction) of platinum group metal for the catalytic
converters made with substrates of the invention is compared with
either 1) a commercially available catalytic converter, made using
wet chemistry, for the application disclosed (e.g., for use on a
gasoline engine or gasoline vehicle), or 2) a catalytic converter
made with wet chemistry, which uses the minimal amount of platinum
group metal to achieve the performance standard indicated.
[0307] In some embodiments, for the above-described comparisons,
both the coated substrate according to the invention, and the
catalyst used in the commercially available catalytic converter or
the catalyst prepared using wet chemistry methods, are aged (by the
same amount) prior to testing. In some embodiments, both the coated
substrate according to the invention, and the catalyst substrate
used in the commercially available catalytic converter or the
catalyst substrate prepared using wet chemistry methods, are aged
to about (or up to about) 50,000 kilometers, about (or up to about)
50,000 miles, about (or up to about) 75,000 kilometers, about (or
up to about) 75,000 miles, about (or up to about) 100,000
kilometers, about (or up to about) 100,000 miles, about (or up to
about) 125,000 kilometers, about (or up to about) 125,000 miles,
about (or up to about) 150,000 kilometers, or about (or up to
about) 150,000 miles. In some embodiments, for the above-described
comparisons, both the coated substrate according to the invention,
and the catalyst substrate used in the commercially available
catalytic converter or the catalyst substrate prepared using wet
chemistry methods, are artificially aged (by the same amount) prior
to testing. In some embodiments, they are artificially aged by
heating to about 400.degree. C., about 500.degree. C., about
600.degree. C., about 700.degree. C., about 800.degree. C., about
900.degree. C., about 1000.degree. C., about 1100.degree. C., or
about 1200.degree. C. for about (or up to about) 4 hours, about (or
up to about) 6 hours, about (or up to about) 8 hours, about (or up
to about) 10 hours, about (or up to about) 12 hours, about (or up
to about) 14 hours, about (or up to about) 16 hours, about (or up
to about) 18 hours, about (or up to about) 20 hours, about (or up
to about) 22 hours, or about (or up to about) 24 hours, or about
(or up to about) 50 hours In some embodiments, they are
artificially aged by heating to about 800.degree. C. for about 16
hours.
[0308] In some embodiments, for the above-described comparisons,
the thrifting (reduction) of platinum group metal for the catalytic
converters made with substrates of the invention is compared with
either 1) a commercially available catalytic converter, made using
wet chemistry, for the application disclosed (e.g., for use on a
gasoline engine or gasoline vehicle), or 2) a catalytic converter
made with wet chemistry, which uses the minimal amount of platinum
group metal to achieve the performance standard indicated, and
after the coated substrate according to the invention and the
catalytic substrate used in the commercially available catalyst or
catalyst made using wet chemistry with the minimal amount of PGM to
achieve the performance standard indicated are aged as described
above.
[0309] In some embodiments, for the above-described catalytic
converters employing the coated substrates of the invention, for
the exhaust treatment systems using catalytic converters employing
the coated substrates of the invention, and for vehicles employing
these catalytic converters and exhaust treatment systems, the
catalytic converter is employed as a diesel oxidation catalyst
along with a diesel particulate filter, or the catalytic converter
is employed as a diesel oxidation catalyst along with a diesel
particulate filter and a selective catalytic reduction unit, to
meet or exceed the standards for CO and/or NO.sub.N, and/or HC
described above.
Exemplary Embodiments
[0310] The invention is further described by the following
embodiments. The features of each of the embodiments are combinable
with any of the other embodiments where appropriate and
practical.
[0311] Embodiment 1. A coated substrate comprising: a substrate; a
washcoat layer comprising oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles, the oxidative catalytically
active Nano-on-Nano-on-micro (NNm) particles comprising composite
nanoparticles bonded to a first micron-sized carrier particle, and
the composite nanoparticles comprising a first support nanoparticle
and an oxidative catalytic nanoparticle; and a washcoat layer
comprising reductive catalytically active Nano-on-Nano-on-micro
(NNm) particles and NO.sub.x trapping particles, the reductive
catalytically active Nano-on-Nano-on-micro (NNm) particles
comprising composite nanoparticles bonded to a second micron-sized
carrier particle, the composite nanoparticles comprising a second
support nanoparticle and a reductive catalytic nanoparticle, and
the NO.sub.x trapping particles comprising micron-sized cerium
oxide.
[0312] Embodiment 2. The coated substrate of embodiment 1, wherein
the NO.sub.x trapping particles further comprise barium oxide
impregnated in the micron-sized cerium oxide.
[0313] Embodiment 3. The coated substrate of embodiment 1 or 2,
wherein the NO.sub.x trapping particles further comprise platinum
and palladium impregnated in the micron-sized cerium oxide.
[0314] Embodiment 4. The coated substrate of embodiment 2, wherein
the barium oxide is plasma-generated.
[0315] Embodiment 5. The coated substrate of embodiment 2, wherein
the barium oxide is impregnated in the micron-sized cerium oxide by
wet chemistry.
[0316] Embodiment 6. The coated substrate of embodiment 3, wherein
the platinum and palladium are plasma-generated.
[0317] Embodiment 7. The coated substrate of embodiment 3, wherein
the platinum and palladium are impregnated in the micron-sized
cerium oxide by wet chemistry.
[0318] Embodiment 8. The coated substrate of embodiment 1, wherein
the NO.sub.x trapping particles further comprise the perovskite
FeBaO.sub.3 impregnated in the micron-sized cerium oxide.
[0319] Embodiment 9. The coated substrate of embodiment 1, wherein
the NO.sub.x trapping particles further comprise metal oxides
selected from the group consisting of samarium, zinc, copper, iron,
and silver impregnated in the micron-sized cerium oxide.
[0320] Embodiment 10. The coated substrate of embodiment 8 or 9,
wherein the NO.sub.x trapping particles are prepared by wet
chemistry.
[0321] Embodiment 11. The coated substrate of any one of
embodiments 8-10, wherein the NO.sub.x trapping particles further
comprise barium oxide impregnated in the micron-sized cerium
oxide.
[0322] Embodiment 12. The coated substrate of embodiment 1, wherein
the NO.sub.x trapping particles further comprise micron-sized
aluminum oxide particles.
[0323] Embodiment 13. The coated substrate of embodiment 12,
wherein the micron-sized aluminum oxide particles are
Nano-on-Nano-on-micro (NNm) particles.
[0324] Embodiment 14. The coated substrate of embodiment 13,
wherein the Nano-on-Nano-on-micro (NNm) particles comprise platinum
and/or palladium.
[0325] Embodiment 15. The coated substrate of embodiment 12,
wherein the Nano-on-Nano-on-micro (NNm) particles comprise a
non-platinum group metal.
[0326] Embodiment 16. The coated substrate of embodiment 15,
wherein the non-platinum group metal is selected from the group
consisting of tungsten, molybdenum, niobium, manganese, and
chromium.
[0327] Embodiment 17. The coated substrate of any one of
embodiments 12-16, further comprising barium oxide impregnated in
the micron-sized cerium oxide particles.
[0328] Embodiment 18. The coated substrate of any one of
embodiments 14-17, wherein the Nano-on-Nano-on-micro (NNm)
particles further comprise barium oxide impregnated in the NNm
particles.
[0329] Embodiment 19. The coated substrate of embodiment 17 or 18,
wherein the barium oxide is impregnated by wet chemistry.
[0330] Embodiment 20. The coated substrate of any one of
embodiments 1-19, wherein the composite nanoparticles are
plasma-generated.
[0331] Embodiment 21. The coated substrate of any one of
embodiments 1-20, wherein the oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles comprise at least one
platinum group metal.
[0332] Embodiment 22. The coated substrate of any one of
embodiments 1-21, wherein the oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles comprise platinum.
[0333] Embodiment 23. The coated substrate of any one of
embodiments 1-21, wherein the oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles comprise palladium.
[0334] Embodiment 24. The coated substrate of any one of
embodiments 1-23, wherein the oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles comprise platinum and
palladium.
[0335] Embodiment 25. The coated substrate of any one of
embodiments 1-24, wherein the first support nanoparticle comprises
aluminum oxide.
[0336] Embodiment 26. The coated substrate of any one of
embodiments 1-25, wherein the second support nanoparticle comprises
cerium oxide.
[0337] Embodiment 27. The coated substrate of any one of
embodiments 1-26, wherein the first micron-sized carrier particle
comprises aluminum oxide.
[0338] Embodiment 28. The coated substrate of any one of
embodiments 1-27, wherein the second micron-sized carrier particle
comprises cerium oxide.
[0339] Embodiment 29. The coated substrate of any one of
embodiments 1-28, wherein the reductive catalytically active
Nano-on-Nano-on-micro (NNm) particles comprise a platinum group
metal.
[0340] Embodiment 30. The coated substrate of embodiment 29,
wherein the platinum group metal is rhodium.
[0341] Embodiment 31. The coated substrate of any one of
embodiments 1-30, wherein the NO.sub.x trapping particles
comprising micron-sized cerium oxide further comprise zirconium
oxide.
[0342] Embodiment 32. The coated substrate of any one of
embodiments 1-31, wherein the support nanoparticles have an average
diameter of about 10 nm to about 20 nm.
[0343] Embodiment 33. The coated substrate of any one of
embodiments 1-31, wherein the support nanoparticles have an average
diameter of about 1 nm to about 5 nm.
[0344] Embodiment 34. The coated substrate of any one of
embodiments 1-33, wherein the washcoat layer comprising oxidative
catalytically active Nano-on-Nano-on-micro (NNm) particles further
comprises metal oxide particles and boehmite particles.
[0345] Embodiment 35. The coated substrate of embodiment 34,
wherein the metal oxide particles are aluminum oxide particles.
[0346] Embodiment 36. The coated substrate of embodiment 35,
wherein the oxidative catalytically active Nano-on-Nano-on-micro
(NNm) particles comprise 35% to 75% by weight of the combination of
the oxidative catalytically active Nano-on-Nano-on-micro (NNm)
particles, boehmite particles, and aluminum oxide particles.
[0347] Embodiment 37. The coated substrate of embodiment 35 or 36,
wherein the aluminum oxide particles comprise 30% to 70% by weight
of the combination of the oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles, boehmite particles, and
aluminum oxide particles.
[0348] Embodiment 38. The coated substrate of any one of
embodiments 35-37, wherein the boehmite particles comprise 2% to 5%
by weight of the combination of the oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles, boehmite particles, and
aluminum oxide particles.
[0349] Embodiment 39. The coated substrate of embodiment 35,
wherein the washcoat layer comprising oxidative catalytically
active Nano-on-Nano-on-micro (NNm) particles comprises 50% by
weight of the oxidative catalytically active Nano-on-Nano-on-micro
(NNm) particles, 3% by weight of the boehmite particles, and 47% by
weight of the aluminum oxide particles.
[0350] Embodiment 40. The coated substrate of any one of
embodiments 1-39, wherein the washcoat layer comprising reductive
catalytically active Nano-on-Nano-on-micro (NNm) particles and
NO.sub.x trapping particles further comprises boehmite.
[0351] Embodiment 41. The coated substrate of embodiment 40,
wherein the reductive catalytically active Nano-on-Nano-on-micro
(NNm) particles comprise 3% to 40% by weight of the combination of
the reductive catalytically active Nano-on-Nano-on-micro (NNm)
particles, NO.sub.x trapping particles, and boehmite particles.
[0352] Embodiment 42. The coated substrate of embodiment 40 or 41,
wherein the NO.sub.x trapping particles comprise 30% to 98% by
weight of the combination of the reductive catalytically active
Nano-on-Nano-on-micro (NNm) particles, NO.sub.x trapping particles,
and boehmite particles.
[0353] Embodiment 43. The coated substrate of any one of
embodiments 40-42, wherein the boehmite particles comprise 1% to 5%
by weight of the combination of the reductive catalytically active
Nano-on-Nano-on-micro (NNm) particles, NO.sub.x trapping particles,
and boehmite particles.
[0354] Embodiment 44. The coated substrate of embodiment 40,
wherein the washcoat layer comprising reductive catalytically
active Nano-on-Nano-on-micro (NNm) particles and NO.sub.x trapping
particles comprises 15% by weight of the reductive catalytically
active Nano-on-Nano-on-micro (NNm) particles, 83% by weight of the
NO.sub.x trapping particles, and 2% by weight of the boehmite
particles.
[0355] Embodiment 45. The coated substrate of any one of
embodiments 1-44, wherein the substrate comprises cordierite.
[0356] Embodiment 46. The coated substrate of any one of
embodiments 1-45, wherein the substrate comprises a honeycomb
structure.
[0357] Embodiment 47. The coated substrate of any one of
embodiments 1-46, wherein the washcoat layer comprising oxidative
catalytically active Nano-on-Nano-on-micro (NNm) particles has a
thickness of 25 g/L to 150 g/L.
[0358] Embodiment 48. The coated substrate of any one of
embodiments 1-47, wherein the washcoat layer comprising reductive
catalytically active Nano-on-Nano-on-micro (NNm) particles and
NO.sub.x trapping particles has a thickness of 100 g/L to 400
g/L.
[0359] Embodiment 49. The coated substrate of any one of
embodiments 1-48, wherein the coated substrate has a platinum group
metal loading of 4 g/L or less and a light-off temperature for
carbon monoxide at least 5.degree. C. lower than the light-off
temperature of a substrate with the same platinum group metal
loading deposited by wet-chemistry methods.
[0360] Embodiment 50. The coated substrate of any one of
embodiments 1-49, said coated substrate having a platinum group
metal loading of about 3.0 g/L to about 5.5 g/L, wherein after
125,000 miles of operation in a vehicular catalytic converter, the
coated substrate has a light-off temperature for carbon monoxide at
least 5.degree. C. lower than a coated substrate prepared by
depositing platinum group metals by wet chemical methods having the
same platinum group metal loading after 125,000 miles of operation
in a vehicular catalytic converter.
[0361] Embodiment 51. The coated substrate of any one of
embodiments 1-50, said coated substrate having a platinum group
metal loading of about 3.0 g/L to about 5.5 g/L, wherein after
aging for 16 hours at 800.degree. C., the coated substrate has a
light-off temperature for carbon monoxide at least 5.degree. C.
lower than a coated substrate prepared by depositing platinum group
metals by wet chemical methods having the same platinum group metal
loading after aging for 16 hours at 800.degree. C.
[0362] Embodiment 52. A catalytic converter comprising a coated
substrate of any one of embodiments 1-51.
[0363] Embodiment 53. An exhaust treatment system comprising a
conduit for exhaust gas and a catalytic converter according to
embodiment 52.
[0364] Embodiment 54. A vehicle comprising a catalytic converter
according to embodiment 52.
[0365] Embodiment 55. A method of treating an exhaust gas,
comprising contacting the coated substrate of any one of
embodiments 1-51 with the exhaust gas.
[0366] Embodiment 56. A method of treating an exhaust gas,
comprising contacting the coated substrate of any one of
embodiments 1-51 with the exhaust gas, wherein the substrate is
housed within a catalytic converter configured to receive the
exhaust gas.
[0367] Embodiment 57. A coated substrate comprising: a substrate; a
washcoat layer comprising oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles, the oxidative catalytically
active Nano-on-Nano-in-Micro (NNiM) particles comprising composite
nanoparticles embedded in a first micron-sized porous carrier, and
the composite nanoparticles comprising a first support nanoparticle
and an oxidative catalytic nanoparticle; and a washcoat layer
comprising reductive catalytically active Nano-on-Nano-in-Micro
(NNiM) particles and NO.sub.x trapping particles, the reductive
catalytically active Nano-on-Nano-in-Micro (NNiM) particles
comprising composite nanoparticles embedded in a second
micron-sized porous carrier, the composite nanoparticles comprising
a second support nanoparticle and a reductive catalytic
nanoparticle, and the NO.sub.x trapping particles comprising
micron-sized cerium oxide.
[0368] Embodiment 58. The coated substrate of embodiment 57,
wherein the NO.sub.x trapping particles further comprise barium
oxide impregnated in the micron-sized cerium oxide.
[0369] Embodiment 59. The coated substrate of embodiment 57 or 58,
wherein the NO.sub.x trapping particles further comprise platinum
and palladium impregnated in the micron-sized cerium oxide.
[0370] Embodiment 60. The coated substrate of embodiment 58,
wherein the barium oxide is plasma-generated.
[0371] Embodiment 61. The coated substrate of embodiment 58,
wherein the barium oxide is impregnated in the micron-sized cerium
oxide by wet chemistry.
[0372] Embodiment 62. The coated substrate of embodiment 59,
wherein the platinum and palladium are plasma-generated.
[0373] Embodiment 63. The coated substrate of embodiment 59,
wherein the platinum and palladium are impregnated in the
micron-sized cerium oxide by wet chemistry.
[0374] Embodiment 64. The coated substrate of embodiment 57,
wherein the NO.sub.x trapping particles further comprise the
perovskite FeBaO.sub.3 impregnated in the micron-sized cerium
oxide.
[0375] Embodiment 65. The coated substrate of embodiment 57,
wherein the NO.sub.x trapping particles further comprise metal
oxides selected from the group consisting of samarium, zinc,
copper, iron, and silver impregnated in the micron-sized cerium
oxide.
[0376] Embodiment 66. The coated substrate of embodiment 64 or 65,
wherein the NO.sub.x trapping particles are prepared by wet
chemistry.
[0377] Embodiment 67. The coated substrate of any one of
embodiments 64-66, wherein the NO.sub.x trapping particles further
comprise barium oxide impregnated in the micron-sized cerium
oxide.
[0378] Embodiment 68. The coated substrate of embodiment 57,
wherein the NO.sub.x trapping particles further comprise
micron-sized aluminum oxide particles.
[0379] Embodiment 69. The coated substrate of embodiment 68,
wherein the micron-sized aluminum oxide particles are
Nano-on-Nano-in-micro (NNiM) particles.
[0380] Embodiment 70. The coated substrate of embodiment 69,
wherein the Nano-on-Nano-in-Micro (NNiM) particles comprise
platinum and/or palladium.
[0381] Embodiment 71. The coated substrate of embodiment 68,
wherein the Nano-on-Nano-in-Micro (NNiM) particles comprise a
non-platinum group metal.
[0382] Embodiment 72. The coated substrate of embodiment 71,
wherein the non-platinum group metal is selected from the group
consisting of tungsten, molybdenum, niobium, manganese, and
chromium.
[0383] Embodiment 73. The coated substrate of any one of
embodiments 68-72, further comprising barium oxide impregnated in
the micron-sized cerium oxide particles.
[0384] Embodiment 74. The coated substrate of any one of
embodiments 68-73, wherein the Nano-on-Nano-in-Micro (NNiM)
particles further comprise barium oxide impregnated in the NNm
particles.
[0385] Embodiment 75. The coated substrate of embodiment 73 or 74,
wherein the barium oxide is impregnated by wet chemistry.
[0386] Embodiment 76. The coated substrate of any one of
embodiments 57-75, wherein the composite nanoparticles are
plasma-generated.
[0387] Embodiment 77. The coated substrate of any one of
embodiments 57-76, wherein the oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles comprise at least one
platinum group metal.
[0388] Embodiment 78. The coated substrate of any one of
embodiments 57-77, wherein the oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles comprise platinum.
[0389] Embodiment 79. The coated substrate of any one of
embodiments 57-77, wherein the oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles comprise palladium.
[0390] Embodiment 80. The coated substrate of any one of
embodiments 57-75, wherein the oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles comprise platinum and
palladium.
[0391] Embodiment 81. The coated substrate of any one of
embodiments 57-80, wherein the first support nanoparticle comprises
aluminum oxide.
[0392] Embodiment 82. The coated substrate of any one of
embodiments 57-81, wherein the second support nanoparticle
comprises cerium oxide.
[0393] Embodiment 83. The coated substrate of any one of
embodiments 57-82, wherein the first micron-sized carrier particle
comprises aluminum oxide.
[0394] Embodiment 84. The coated substrate of any one of
embodiments 57-83, wherein the second micron-sized carrier particle
comprises cerium oxide.
[0395] Embodiment 85. The coated substrate of any one of
embodiments 57-84, wherein the reductive catalytically active
Nano-on-Nano-in-Micro (NNiM) particles comprise a platinum group
metal.
[0396] Embodiment 86. The coated substrate of embodiment 85,
wherein the platinum group metal is rhodium.
[0397] Embodiment 87. The coated substrate of any one of
embodiments 57-86, wherein the NO.sub.x trapping particles
comprising micron-sized cerium oxide further comprise zirconium
oxide.
[0398] Embodiment 88. The coated substrate of any one of
embodiments 57-87, wherein the support nanoparticles have an
average diameter of about 10 nm to about 20 nm.
[0399] Embodiment 89. The coated substrate of any one of
embodiments 57-87, wherein the support nanoparticles have an
average diameter of about 1 nm to about 5 nm.
[0400] Embodiment 90. The coated substrate of any one of
embodiments 57-89, wherein the washcoat layer comprising oxidative
catalytically active Nano-on-Nano-in-Micro (NNiM) particles further
comprises metal oxide particles and boehmite particles.
[0401] Embodiment 91. The coated substrate of embodiment 90,
wherein the metal oxide particles are aluminum oxide particles.
[0402] Embodiment 92. The coated substrate of embodiment 91,
wherein the oxidative catalytically active Nano-on-Nano-in-Micro
(NNiM) particles comprise 35% to 75% by weight of the combination
of the oxidative catalytically active Nano-on-Nano-in-Micro (NNiM)
particles, boehmite particles, and aluminum oxide particles.
[0403] Embodiment 93. The coated substrate of embodiment 91 or 92,
wherein the aluminum oxide particles comprise 30% to 70% by weight
of the combination of the oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles, boehmite particles, and
aluminum oxide particles.
[0404] Embodiment 94. The coated substrate of any one of
embodiments 91-93, wherein the boehmite particles comprise 2% to 5%
by weight of the combination of the oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles, boehmite particles, and
aluminum oxide particles.
[0405] Embodiment 95. The coated substrate of embodiment 91,
wherein the washcoat layer comprising oxidative catalytically
active Nano-on-Nano-in-Micro (NNiM) particles comprises 50% by
weight of the oxidative catalytically active Nano-on-Nano-in-Micro
(NNiM) particles, 3% by weight of the boehmite particles, and 47%
by weight of the aluminum oxide particles.
[0406] Embodiment 96. The coated substrate of any one of
embodiments 57-95, wherein the washcoat layer comprising reductive
catalytically active Nano-on-Nano-in-Micro (NNiM) particles and
NO.sub.x trapping particles further comprises boehmite.
[0407] Embodiment 97. The coated substrate of embodiment 96,
wherein the reductive catalytically active Nano-on-Nano-in-Micro
(NNiM) particles comprise 3% to 40% by weight of the combination of
the reductive catalytically active Nano-on-Nano-in-Micro (NNiM)
particles, NO.sub.x trapping particles, and boehmite particles.
[0408] Embodiment 98. The coated substrate of embodiment 96 or 97,
wherein the NO.sub.x trapping particles comprise 30% to 98% by
weight of the combination of the reductive catalytically active
Nano-on-Nano-in-Micro (NNiM) particles, NO.sub.x trapping
particles, and boehmite particles.
[0409] Embodiment 99. The coated substrate of any one of
embodiments 96-98, wherein the boehmite particles comprise 1% to 5%
by weight of the combination of the reductive catalytically active
Nano-on-Nano-in-Micro (NNiM) particles, NO.sub.x trapping
particles, and boehmite particles.
[0410] Embodiment 100. The coated substrate of embodiment 96,
wherein the washcoat layer comprising reductive catalytically
active Nano-on-Nano-in-Micro (NNiM) particles and NO.sub.x trapping
particles comprises 15% by weight of the reductive catalytically
active Nano-on-Nano-in-Micro (NNiM) particles, 83% by weight of the
NO.sub.x trapping particles, and 2% by weight of the boehmite
particles.
[0411] Embodiment 101. The coated substrate of any one of
embodiments 57-100, wherein the substrate comprises cordierite.
[0412] Embodiment 102. The coated substrate of any one of
embodiments 57-101, wherein the substrate comprises a honeycomb
structure.
[0413] Embodiment 103. The coated substrate of any one of
embodiments 57-102, wherein the washcoat layer comprising oxidative
catalytically active Nano-on-Nano-in-Micro (NNiM) particles has a
thickness of 25 g/L to 150 g/L.
[0414] Embodiment 104. The coated substrate of any one of
embodiments 57-103, wherein the washcoat layer comprising reductive
catalytically active Nano-on-Nano-in-Micro (NNiM) particles and
NO.sub.x trapping particles has a thickness of 100 g/L to 400
g/L.
[0415] Embodiment 105. The coated substrate of any one of
embodiments 57-104, wherein the coated substrate has a platinum
group metal loading of 4 g/L or less and a light-off temperature
for carbon monoxide at least 5.degree. C. lower than the light-off
temperature of a substrate with the same platinum group metal
loading deposited by wet-chemistry methods.
[0416] Embodiment 106. The coated substrate of any one of
embodiments 57-105, said coated substrate having a platinum group
metal loading of about 3.0 g/L to about 5.5 g/L, wherein after
125,000 miles of operation in a vehicular catalytic converter, the
coated substrate has a light-off temperature for carbon monoxide at
least 5.degree. C. lower than a coated substrate prepared by
depositing platinum group metals by wet chemical methods having the
same platinum group metal loading after 125,000 miles of operation
in a vehicular catalytic converter.
[0417] Embodiment 107. The coated substrate of any one of
embodiments 57-106, said coated substrate having a platinum group
metal loading of about 3.0 g/L to about 5.5 g/L, wherein after
aging for 16 hours at 800.degree. C., the coated substrate has a
light-off temperature for carbon monoxide at least 5.degree. C.
lower than a coated substrate prepared by depositing platinum group
metals by wet chemical methods having the same platinum group metal
loading after aging for 16 hours at 800.degree. C.
[0418] Embodiment 108. A catalytic converter comprising a coated
substrate of any one of embodiments 57-107.
[0419] Embodiment 109. An exhaust treatment system comprising a
conduit for exhaust gas and a catalytic converter according to
embodiment 108.
[0420] Embodiment 110. A vehicle comprising a catalytic converter
according to embodiment 108.
[0421] Embodiment 111. A method of treating an exhaust gas,
comprising contacting the coated substrate of any one of
embodiments 57-107 with the exhaust gas.
[0422] Embodiment 112. A method of treating an exhaust gas,
comprising contacting the coated substrate of any one of
embodiments 57-107 with the exhaust gas, wherein the substrate is
housed within a catalytic converter configured to receive the
exhaust gas.
[0423] Embodiment 113. A coated substrate comprising: a substrate;
a washcoat layer comprising oxidative catalytically active
composite nanoparticles attached to a first micron-sized support
particle, the oxidative catalytically active composite
nanoparticles being plasma-generated and comprising a first support
nanoparticle and an oxidative catalytic nanoparticle; and a
washcoat layer comprising NO.sub.x trapping particles and reductive
catalytically active composite nanoparticles attached to a second
micron-sized support particle, the reductive catalytically active
composite nanoparticles being plasma-generated and comprising a
second support nanoparticle and a reductive catalytic nanoparticle,
and the NO.sub.x trapping particles comprising micron-sized cerium
oxide.
[0424] Embodiment 114. The coated substrate of embodiment 113,
wherein the NO.sub.x trapping particles further comprise barium
oxide impregnated in the micron-sized cerium oxide.
[0425] Embodiment 115. The coated substrate of embodiment 113 or
114, wherein the NO.sub.x trapping particles further comprise
platinum and palladium impregnated in the micron-sized cerium
oxide.
[0426] Embodiment 116. The coated substrate of embodiment 114,
wherein the barium oxide is plasma-generated.
[0427] Embodiment 117. The coated substrate of embodiment 114,
wherein the barium oxide is impregnated in the micron-sized cerium
oxide by wet chemistry.
[0428] Embodiment 118. The coated substrate of embodiment 115,
wherein the platinum and palladium are plasma-generated.
[0429] Embodiment 119. The coated substrate of embodiment 115,
wherein the platinum and palladium are impregnated in the
micron-sized cerium oxide by wet chemistry.
[0430] Embodiment 120. The coated substrate of embodiment 113,
wherein the NO.sub.x trapping particles further comprise the
perovskite FeBaO.sub.3 impregnated in the micron-sized cerium
oxide.
[0431] Embodiment 121. The coated substrate of embodiment 113,
wherein the NO.sub.x trapping particles further comprise metal
oxides selected from the group consisting of samarium, zinc,
copper, iron, and silver impregnated in the micron-sized cerium
oxide.
[0432] Embodiment 122. The coated substrate of embodiment 120 or
121, wherein the NO.sub.x trapping particles are prepared by wet
chemistry.
[0433] Embodiment 123. The coated substrate of any one of
embodiments 120-122, wherein the NO.sub.x trapping particles
further comprise barium oxide impregnated in the micron-sized
cerium oxide.
[0434] Embodiment 124. The coated substrate of embodiment 113,
wherein the NO.sub.x trapping particles further comprise
micron-sized aluminum oxide particles.
[0435] Embodiment 125. The coated substrate of embodiment 124,
wherein the micron-sized aluminum oxide particles are
Nano-on-Nano-on-micro (NNm) particles or Nano-on-Nano-in-Micro
(NNiM) particles.
[0436] Embodiment 126. The coated substrate of embodiment 125,
wherein the Nano-on-Nano-on-micro (NNm) particles or
Nano-on-Nano-in-Micro (NNiM) particles comprise platinum and/or
palladium.
[0437] Embodiment 127. The coated substrate of embodiment 124,
wherein the Nano-on-Nano-on-micro (NNm) particles comprise a
non-platinum group metal.
[0438] Embodiment 128. The coated substrate of embodiment 127,
wherein the non-platinum group metal is selected from the group
consisting of tungsten, molybdenum, niobium, manganese, and
chromium.
[0439] Embodiment 129. The coated substrate of any one of
embodiments 124-128, further comprising barium oxide impregnated in
the micron-sized cerium oxide particle.
[0440] Embodiment 130. The coated substrate of any one of
embodiments 124-129, wherein the Nano-on-Nano-on-micro (NNm)
particles or Nano-on-Nano-in-Micro (NNiM) particles further
comprise barium oxide impregnated in the NNm or NNiM particles.
[0441] Embodiment 131. The coated substrate of embodiment 129 or
130, wherein the barium oxide is impregnated by wet chemistry.
[0442] Embodiment 132. The coated substrate of embodiment any one
of embodiments 113-131, wherein the oxidative catalytically active
composite nanoparticles attached to a first micron-sized support
particle comprise oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles.
[0443] Embodiment 133. The coated substrate of embodiment 113-131,
wherein the oxidative catalytically active composite nanoparticles
attached to a first micron-sized support particle comprise
oxidative catalytically active Nano-on-Nano-in-Micro (NNiM)
particles.
[0444] Embodiment 134. The coated substrate of any one of
embodiments 113-133, wherein the oxidative catalytically active
composite nanoparticles comprise at least one platinum group
metal.
[0445] Embodiment 135. The coated substrate of any one of
embodiment 113-134, wherein the oxidative catalytically active
composite nanoparticles comprise platinum.
[0446] Embodiment 136. The coated substrate of any one of
embodiment 113-134, wherein the oxidative catalytically active
composite nanoparticles comprise palladium.
[0447] Embodiment 137. The coated substrate of any one of
embodiments 113-136, wherein the oxidative catalytically active
composite nanoparticles comprise platinum and palladium.
[0448] Embodiment 138. The coated substrate of any one of
embodiments 113-137, wherein the first support nanoparticle
comprises aluminum oxide.
[0449] Embodiment 139. The coated substrate of any one of
embodiments 113-138, wherein the second support nanoparticle
comprises cerium oxide.
[0450] Embodiment 140. The coated substrate of any one of
embodiments 113-139, wherein the first micron-sized support
particle comprises aluminum oxide.
[0451] Embodiment 141. The coated substrate of any one of
embodiments 113-140, wherein the second micron-sized support
particle comprises cerium oxide.
[0452] Embodiment 142. The coated substrate of any one of
embodiments 113-141, wherein the reductive catalytically active
composite nanoparticles comprise reductive catalytically active
Nano-on-Nano-on-micro (NNm) particles.
[0453] Embodiment 143. The coated substrate of embodiment 142,
wherein the reductive catalytically active Nano-on-Nano-on-micro
(NNm) particles comprise a platinum group metal.
[0454] Embodiment 144. The coated substrate of any one of
embodiments 113-141, wherein the reductive catalytically active
composite nanoparticles comprise reductive catalytically active
Nano-on-Nano-in-Micro (NNiM) particles.
[0455] Embodiment 145. The coated substrate of embodiment 144,
wherein the reductive catalytically active Nano-on-Nano-in-Micro
(NNiM) particles comprise a platinum group metal.
[0456] Embodiment 146. The coated substrate of embodiment 143 or
145, wherein the platinum group metal is rhodium.
[0457] Embodiment 147. The coated substrate of any one of
embodiments 113-146, wherein the NO.sub.x trapping particles
further comprise zirconium oxide.
[0458] Embodiment 148. The coated substrate of any one of
embodiments 113-147, wherein the support nanoparticles have an
average diameter of about 10 nm to about 20 nm.
[0459] Embodiment 149. The coated substrate of any one of
embodiments 113-147, wherein the support nanoparticles have an
average diameter of about 1 nm to about 5 nm.
[0460] Embodiment 150. The coated substrate of embodiment 132,
wherein the washcoat layer comprising oxidative catalytically
active Nano-on-Nano-on-micro (NNm) particles further comprises
metal oxide particles and boehmite particles.
[0461] Embodiment 151. The coated substrate of embodiment 150,
wherein the metal oxide particles are aluminum oxide particles.
[0462] Embodiment 152. The coated substrate of embodiment 151,
wherein the oxidative catalytically active Nano-on-Nano-on-micro
(NNm) particles comprise 35% to 75% by weight of the combination of
the oxidative catalytically active Nano-on-Nano-on-micro (NNm)
particles, boehmite particles, and aluminum oxide particles.
[0463] Embodiment 153. The coated substrate of embodiment 151 or
152, wherein the aluminum oxide particles comprise 30% to 70% by
weight of the combination of the oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles, boehmite particles, and
aluminum oxide particles.
[0464] Embodiment 154. The coated substrate of any one of
embodiments 151-153, wherein the boehmite particles comprise 2% to
5% by weight of the combination of the oxidative catalytically
active Nano-on-Nano-on-micro (NNm) particles, boehmite particles,
and aluminum oxide particles.
[0465] Embodiment 155. The coated substrate of embodiment 151,
wherein the washcoat layer comprising oxidative catalytically
active Nano-on-Nano-on-micro (NNm) particles comprises 50% by
weight of the oxidative catalytically active Nano-on-Nano-on-micro
(NNm) particles, 3% by weight of the boehmite particles, and 47% by
weight of the aluminum oxide particles.
[0466] Embodiment 156. The coated substrate of embodiment 133,
wherein the washcoat layer comprising oxidative catalytically
active Nano-on-Nano-in-Micro (NNiM) particles further comprises
metal oxide particles and boehmite particles.
[0467] Embodiment 157. The coated substrate of embodiment 156,
wherein the metal oxide particles are aluminum oxide particles.
[0468] Embodiment 158. The coated substrate of embodiment 157,
wherein the oxidative catalytically active Nano-on-Nano-in-Micro
(NNiM) particles comprise 35% to 75% by weight of the combination
of the oxidative catalytically active Nano-on-Nano-in-Micro (NNiM)
particles, boehmite particles, and aluminum oxide particles.
[0469] Embodiment 159. The coated substrate of embodiment 157 or
158, wherein the aluminum oxide particles comprise 30% to 70% by
weight of the combination of the oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles, boehmite particles, and
aluminum oxide particles.
[0470] Embodiment 160. The coated substrate of any one of
embodiments 157-159, wherein the boehmite particles comprise 2% to
5% by weight of the combination of the oxidative catalytically
active Nano-on-Nano-in-Micro (NNiM) particles, boehmite particles,
and aluminum oxide particles.
[0471] Embodiment 161. The coated substrate of embodiment 157,
wherein the washcoat layer comprising oxidative catalytically
active Nano-on-Nano-in-Micro (NNiM) particles comprises 50% by
weight of the oxidative catalytically active Nano-on-Nano-in-Micro
(NNiM) particles, 3% by weight of the boehmite particles, and 47%
by weight of the aluminum oxide particles.
[0472] Embodiment 162. The coated substrate of embodiment 142,
wherein the washcoat layer comprising reductive catalytically
active Nano-on-Nano-on-micro (NNm) particles and NO.sub.x trapping
particles further comprises boehmite.
[0473] Embodiment 163. The coated substrate of embodiment 162,
wherein the reductive catalytically active Nano-on-Nano-on-micro
(NNm) particles comprise 3% to 40% by weight of the combination of
the reductive catalytically active Nano-on-Nano-on-micro (NNm)
particles, NO.sub.x trapping particles, and boehmite particles.
[0474] Embodiment 164. The coated substrate of embodiment 162 or
163, wherein the NO.sub.x trapping particles comprise 30% to 98% by
weight of the combination of the reductive catalytically active
Nano-on-Nano-on-micro (NNm) particles, NO.sub.x trapping particles,
and boehmite particles.
[0475] Embodiment 165. The coated substrate of any one of
embodiments 162-164, wherein the boehmite particles comprise 1% to
5% by weight of the combination of the reductive catalytically
active Nano-on-Nano-on-micro (NNm) particles, NO.sub.x trapping
particles, and boehmite particles.
[0476] Embodiment 166. The coated substrate of embodiment 162,
wherein the washcoat layer comprising reductive catalytically
active Nano-on-Nano-on-micro (NNm) particles and NO.sub.x trapping
particles comprises 15% by weight of the reductive catalytically
active Nano-on-Nano-on-micro (NNm) particles, 83% by weight of the
NO.sub.x trapping particles, and 2% by weight of the boehmite
particles.
[0477] Embodiment 167. The coated substrate of embodiment 144,
wherein the washcoat layer comprising reductive catalytically
active Nano-on-Nano-in-Micro (NNiM) particles and NO.sub.x trapping
particles further comprises boehmite.
[0478] Embodiment 168. The coated substrate of embodiment 167,
wherein the reductive catalytically active Nano-on-Nano-in-Micro
(NNiM) particles comprise 3% to 40% by weight of the combination of
the reductive catalytically active Nano-on-Nano-in-Micro (NNiM)
particles, NO.sub.x trapping particles, and boehmite particles.
[0479] Embodiment 169. The coated substrate of embodiment 167 or
168, wherein the cerium oxide particles comprise 30% to 98% by
weight of the combination of the reductive catalytically active
Nano-on-Nano-in-Micro (NNiM) particles, NO.sub.x trapping
particles, and boehmite particles.
[0480] Embodiment 170. The coated substrate of any one of
embodiments 167-169, wherein the boehmite particles comprise 1% to
5% by weight of the combination of the reductive catalytically
active Nano-on-Nano-in-Micro (NNiM) particles, NO.sub.x trapping
particles, and boehmite particles.
[0481] Embodiment 171. The coated substrate of embodiment 167,
wherein the washcoat layer comprising reductive catalytically
active Nano-on-Nano-in-Micro (NNiM) particles and NO.sub.x trapping
particles comprises 15% by weight of the reductive catalytically
active Nano-on-Nano-in-Micro (NNiM) particles, 83% by weight of the
NO.sub.x trapping particles, and 2% by weight of the boehmite
particles.
[0482] Embodiment 172. The coated substrate of any one of
embodiments 113-171, wherein the substrate comprises
cordierite.
[0483] Embodiment 173. The coated substrate of any one of
embodiments 113-172, wherein the substrate comprises a honeycomb
structure.
[0484] Embodiment 174. The coated substrate of embodiment 132,
wherein the washcoat layer comprising oxidative catalytically
active Nano-on-Nano-on-micro (NNm) particles has a thickness of 25
g/L to 150 g/L.
[0485] Embodiment 175. The coated substrate of embodiment 133,
wherein the washcoat layer comprising oxidative catalytically
active Nano-on-Nano-in-Micro (NNiM) particles has a thickness of 25
g/L to 150 g/L.
[0486] Embodiment 176. The coated substrate of embodiment 142,
wherein the washcoat layer comprising reductive catalytically
active Nano-on-Nano-on-micro (NNm) particles and NO.sub.x trapping
particles has a thickness of 100 g/L to 400 g/L.
[0487] Embodiment 177. The coated substrate of embodiment 144,
wherein the washcoat layer comprising reductive catalytically
active Nano-on-Nano-in-Micro (NNiM) particles and NO.sub.x trapping
particles has a thickness of 100 g/L to 400 g/L.
[0488] Embodiment 178. The coated substrate of any one of
embodiments 113-177, wherein the coated substrate has a platinum
group metal loading of 4 g/L or less and a light-off temperature
for carbon monoxide at least 5.degree. C. lower than the light-off
temperature of a substrate with the same platinum group metal
loading deposited by wet-chemistry methods.
[0489] Embodiment 179. The coated substrate of any one of
embodiments 113-177, said coated substrate having a platinum group
metal loading of about 3.0 g/L to about 5.5 g/L, wherein after
125,000 miles of operation in a vehicular catalytic converter, the
coated substrate has a light-off temperature for carbon monoxide at
least 5.degree. C. lower than a coated substrate prepared by
depositing platinum group metals by wet chemical methods having the
same platinum group metal loading after 125,000 miles of operation
in a vehicular catalytic converter.
[0490] Embodiment 180. The coated substrate of any one of
embodiments 113-178, said coated substrate having a platinum group
metal loading of about 3.0 g/L to about 5.5 g/L, wherein after
aging for 16 hours at 800.degree. C., the coated substrate has a
light-off temperature for carbon monoxide at least 5.degree. C.
lower than a coated substrate prepared by depositing platinum group
metals by wet chemical methods having the same platinum group metal
loading after aging for 16 hours at 800.degree. C.
[0491] Embodiment 181. A catalytic converter comprising a coated
substrate of any one of embodiments 113-180.
[0492] Embodiment 182. An exhaust treatment system comprising a
conduit for exhaust gas and a catalytic converter according to
embodiment 181.
[0493] Embodiment 183. A vehicle comprising a catalytic converter
according to embodiment 181.
[0494] Embodiment 184. A method of treating an exhaust gas,
comprising contacting the coated substrate of any one of
embodiments 113-180 with the exhaust gas.
[0495] Embodiment 185. A method of treating an exhaust gas,
comprising contacting the coated substrate of any one of
embodiments 113-180 with the exhaust gas, wherein the substrate is
housed within a catalytic converter configured to receive the
exhaust gas.
[0496] Embodiment 186. A coated substrate comprising: a substrate;
a washcoat layer comprising oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles, the oxidative catalytically
active Nano-on-Nano-on-micro (NNm) particles comprising composite
nanoparticles bonded to a first micron-sized carrier particle, and
the composite nanoparticles comprising a first support nanoparticle
and an oxidative catalytic nanoparticle; a washcoat layer
comprising reductive catalytically active Nano-on-Nano-on-micro
(NNm) particles, the reductive catalytically active
Nano-on-Nano-on-micro (NNm) particles comprising composite
nanoparticles bonded to a second micron-sized carrier particle, and
the composite nanoparticles comprising a second support
nanoparticle and a reductive catalytic nanoparticle; and a washcoat
layer comprising NO.sub.x trapping particles, and the NO.sub.x
trapping particles comprising micron-sized cerium oxide.
[0497] Embodiment 187. The coated substrate of embodiment 186,
wherein the NO.sub.x trapping particles further comprise barium
oxide impregnated in the micron-sized cerium oxide.
[0498] Embodiment 188. The coated substrate of embodiment 186 or
187, wherein the NO.sub.x trapping particles further comprise
platinum and palladium impregnated in the micron-sized cerium
oxide.
[0499] Embodiment 189. The coated substrate of embodiment 187,
wherein the barium oxide is plasma-generated.
[0500] Embodiment 190. The coated substrate of embodiment 187,
wherein the barium oxide is impregnated in the micron-sized cerium
oxide by wet chemistry.
[0501] Embodiment 191. The coated substrate of embodiment 188,
wherein the platinum and palladium are plasma-generated.
[0502] Embodiment 192. The coated substrate of embodiment 188,
wherein the platinum and palladium are impregnated in the
micron-sized cerium oxide by wet chemistry.
[0503] Embodiment 193. The coated substrate of embodiment 186,
wherein the NO.sub.x trapping particles further comprise the
perovskite FeBaO.sub.3 impregnated in the micron-sized cerium
oxide.
[0504] Embodiment 194. The coated substrate of embodiment 186,
wherein the NO.sub.x trapping particles further comprise metal
oxides selected from the group consisting of samarium, zinc,
copper, iron, and silver impregnated in the micron-sized cerium
oxide.
[0505] Embodiment 195. The coated substrate of embodiment 193 or
194, wherein the NO.sub.x trapping particles are prepared by wet
chemistry.
[0506] Embodiment 196. The coated substrate of any one of
embodiments 193-195, wherein the NO.sub.x trapping particles
further comprise barium oxide impregnated in the micron-sized
cerium oxide.
[0507] Embodiment 197. The coated substrate of embodiment 186,
wherein the NO.sub.x trapping particles further comprise
micron-sized aluminum oxide particles.
[0508] Embodiment 198. The coated substrate of embodiment 197,
wherein the micron-sized aluminum oxide particles are
Nano-on-Nano-on-micro (NNm) particles.
[0509] Embodiment 199. The coated substrate of embodiment 198,
wherein the Nano-on-Nano-on-micro (NNm) particles comprise platinum
and/or palladium.
[0510] Embodiment 200. The coated substrate of embodiment 197,
wherein the Nano-on-Nano-on-micro (NNm) particles comprise a
non-platinum group metal.
[0511] Embodiment 201. The coated substrate of embodiment 200,
wherein the non-platinum group metal is selected from the group
consisting of tungsten, molybdenum, niobium, manganese, and
chromium.
[0512] Embodiment 202. The coated substrate of any one of
embodiments 197-201, further comprising barium oxide impregnated in
the micron-sized cerium oxide particles.
[0513] Embodiment 203. The coated substrate of any one of
embodiments 197-202, wherein the Nano-on-Nano-on-micro (NNm)
particles further comprise barium oxide impregnated in the NNm
particles.
[0514] Embodiment 204. The coated substrate of embodiment 202 or
203, wherein the barium oxide is impregnated by wet chemistry.
[0515] Embodiment 205. The coated substrate of any one of
embodiment 186-204, wherein the composite nanoparticles are
plasma-generated.
[0516] Embodiment 206. The coated substrate of any one of
embodiments 186-205, wherein the oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles comprise at least one
platinum group metal.
[0517] Embodiment 207. The coated substrate of any one of
embodiments 186-206, wherein the oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles comprise platinum.
[0518] Embodiment 208. The coated substrate of any one of
embodiments 186-206, wherein the oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles comprise palladium.
[0519] Embodiment 209. The coated substrate of any one of
embodiments 186-208, wherein the oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles comprise platinum and
palladium.
[0520] Embodiment 210. The coated substrate of any one of
embodiments 186-209, wherein the first support nanoparticle
comprises aluminum oxide.
[0521] Embodiment 211. The coated substrate of any one of
embodiments 186-210, wherein the second support nanoparticle
comprises cerium oxide.
[0522] Embodiment 212. The coated substrate of any one of
embodiments 186-211, wherein the first micron-sized carrier
particle comprises aluminum oxide.
[0523] Embodiment 213. The coated substrate of any one of
embodiments 186-212, wherein the second micron-sized carrier
particle comprises cerium oxide.
[0524] Embodiment 214. The coated substrate of any one of
embodiments 186-213, wherein the reductive catalytically active
Nano-on-Nano-on-micro (NNm) particles comprise a platinum group
metal.
[0525] Embodiment 215. The coated substrate of embodiment 214,
wherein the platinum group metal is rhodium.
[0526] Embodiment 216. The coated substrate of any one of
embodiments 186-215, wherein the NO.sub.x trapping particles
further comprise zirconium oxide.
[0527] Embodiment 217. The coated substrate of any one of
embodiments 186-216, wherein the support nanoparticles have an
average diameter of about 10 nm to about 20 nm.
[0528] Embodiment 218. The coated substrate of any one of
embodiments 186-216, wherein the support nanoparticles have an
average diameter of about 1 nm to about 5 nm.
[0529] Embodiment 219. The coated substrate of any one of
embodiments 186-218, wherein the washcoat layer comprising
oxidative catalytically active Nano-on-Nano-on-micro (NNm)
particles further comprises metal oxide particles and boehmite
particles.
[0530] Embodiment 220. The coated substrate of embodiment 219,
wherein the metal oxide particles are aluminum oxide particles.
[0531] Embodiment 221. The coated substrate of embodiment 220,
wherein the oxidative catalytically active Nano-on-Nano-on-micro
(NNm) particles comprise 35% to 75% by weight of the combination of
the oxidative catalytically active Nano-on-Nano-on-micro (NNm)
particles, boehmite particles, and aluminum oxide particles.
[0532] Embodiment 222. The coated substrate of embodiment 220 or
221, wherein the aluminum oxide particles comprise 30% to 70% by
weight of the combination of the oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles, boehmite particles, and
aluminum oxide particles.
[0533] Embodiment 223. The coated substrate of any one of
embodiments 220-222, wherein the beohmite particles comprise 2% to
5% by weight of the combination of the oxidative catalytically
active Nano-on-Nano-on-micro (NNm) particles, boehmite particles,
and aluminum oxide particles.
[0534] Embodiment 224. The coated substrate of embodiment 220,
wherein the washcoat layer comprising oxidative catalytically
active Nano-on-Nano-on-micro (NNm) particles comprises 50% by
weight of the oxidative catalytically active Nano-on-Nano-on-micro
(NNm) particles, 3% by weight of the boehmite particles, and 47% by
weight of the aluminum oxide particles.
[0535] Embodiment 225. The coated substrate of any one of
embodiments 186-224, wherein the washcoat layer comprising
reductive catalytically active Nano-on-Nano-on-micro (NNm)
particles further comprises metal oxide particles and boehmite
particles.
[0536] Embodiment 226. The coated substrate of embodiment 225,
wherein the metal oxide particles are aluminum oxide particles.
[0537] Embodiment 227. The coated substrate of embodiment 226,
wherein the reductive catalytically active Nano-on-Nano-on-micro
(NNm) particles comprise 50% to 95% by weight of the combination of
the reductive catalytically active Nano-on-Nano-on-micro (NNm)
particles, aluminum oxide particles, and boehmite particles.
[0538] Embodiment 228. The coated substrate of embodiment 226 or
227, wherein the aluminum oxide particles comprise 5% to 40% by
weight of the combination of the reductive catalytically active
Nano-on-Nano-on-micro (NNm) particles, aluminum oxide particles,
and boehmite particles.
[0539] Embodiment 229. The coated substrate of any one of
embodiments 226-228, wherein the boehmite particles comprise 2% to
5% by weight of the combination of the reductive catalytically
active Nano-on-Nano-on-micro (NNm) particles, aluminum oxide
particles, and boehmite particles.
[0540] Embodiment 230. The coated substrate of embodiment 226,
wherein the washcoat layer comprising reductive catalytically
active Nano-on-Nano-on-micro (NNm) particles comprises 80% by
weight of the reductive catalytically active Nano-on-Nano-on-micro
(NNm) particles, 17% by weight of the aluminum oxide particles, and
3% by weight of the boehmite particles.
[0541] Embodiment 231. The coated substrate of any one of
embodiments 186-230, wherein the washcoat layer comprising NO.sub.x
trapping particles further comprises Nano-on-Nano-on-micro (NNm)
particles and boehmite particles.
[0542] Embodiment 232. The coated substrate of embodiment 231,
wherein the Nano-on-Nano-on-micro (NNm) particles comprise a
platinum group metal.
[0543] Embodiment 233. The coated substrate of embodiment 232,
wherein the platinum group metal is selected from the group
consisting of ruthenium, platinum, and palladium.
[0544] Embodiment 234. The coated substrate of embodiment 231,
wherein the NO.sub.x trapping Nano-on-Nano-on-micro (NNm) particles
comprise a non-platinum group metal.
[0545] Embodiment 235. The coated substrate of embodiment 234,
wherein the non-platinum group metal is selected from the group
consisting of tungsten, molybdenum, niobium, manganese, and
chromium.
[0546] Embodiment 236. The coated substrate of any one of
embodiments 231-235, wherein the Nano-on-Nano-on-micro (NNm)
particles comprise 10% to 40% by weight of the combination of the
Nano-on-Nano-on-micro (NNm) particles, NO.sub.x trapping particles,
and boehmite particles.
[0547] Embodiment 237. The coated substrate of any one of
embodiments 231-236, wherein the micron-sized cerium oxide
particles comprise 50% to 90% by weight of the combination of the
Nano-on-Nano-on-micro (NNm) particles, NO.sub.x trapping particles,
and boehmite particles.
[0548] Embodiment 238. The coated substrate of any one of
embodiments 231-237, wherein the boehmite particles comprise 2% to
5% by weight of the combination of the Nano-on-Nano-on-micro (NNm)
particles, NO.sub.x trapping particles, and boehmite particles.
[0549] Embodiment 239. The coated substrate of any one of
embodiments 231-238, wherein the washcoat layer comprising
micron-sized cerium oxide particles comprises 73% by weight of the
NO.sub.x trapping particles, 23% by weight of the
Nano-on-Nano-on-micro (NNm) particles, and 4% by weight of the
boehmite particles.
[0550] Embodiment 240. The coated substrate of any one of
embodiments 186-239, wherein the substrate comprises
cordierite.
[0551] Embodiment 241. The coated substrate of any one of
embodiments 186-240, wherein the substrate comprises a honeycomb
structure.
[0552] Embodiment 242. The coated substrate of any one of
embodiments 186-241, wherein the washcoat layer comprising
oxidative catalytically active Nano-on-Nano-on-micro (NNm)
particles has a thickness of 25 g/L to 150 g/L.
[0553] Embodiment 243. The coated substrate of any one of
embodiments 186-242, wherein the washcoat layer comprising
reductive catalytically active Nano-on-Nano-on-micro (NNm)
particles has a thickness of 25 g/L to 150 g/L.
[0554] Embodiment 244. The coated substrate of any one of
embodiments 186-243, wherein the washcoat layer comprising NO.sub.x
trapping particles has a thickness of 100 g/L to 400 g/L.
[0555] Embodiment 245. The coated substrate of any one of
embodiments 186-244, wherein the coated substrate has a platinum
group metal loading of 4 g/L or less and a light-off temperature
for carbon monoxide at least 5.degree. C. lower than the light-off
temperature of a substrate with the same platinum group metal
loading deposited by wet-chemistry methods.
[0556] Embodiment 246. The coated substrate of any one of
embodiments 186-245, said coated substrate having a platinum group
metal loading of about 3.0 g/L to about 5.5 g/L, wherein after
125,000 miles of operation in a vehicular catalytic converter, the
coated substrate has a light-off temperature for carbon monoxide at
least 5.degree. C. lower than a coated substrate prepared by
depositing platinum group metals by wet chemical methods having the
same platinum group metal loading after 125,000 miles of operation
in a vehicular catalytic converter.
[0557] Embodiment 247. The coated substrate of any one of
embodiments 186-246 said coated substrate having a platinum group
metal loading of about 3.0 g/L to about 5.5 g/L, wherein after
aging for 16 hours at 800.degree. C., the coated substrate has a
light-off temperature for carbon monoxide at least 5.degree. C.
lower than a coated substrate prepared by depositing platinum group
metals by wet chemical methods having the same platinum group metal
loading after aging for 16 hours at 800.degree. C.
[0558] Embodiment 248. A catalytic converter comprising a coated
substrate of any one of embodiments 186-247.
[0559] Embodiment 249. An exhaust treatment system comprising a
conduit for exhaust gas and a catalytic converter according to
embodiment 248.
[0560] Embodiment 250. A vehicle comprising a catalytic converter
according to embodiment 248.
[0561] Embodiment 251. A method of treating an exhaust gas,
comprising contacting the coated substrate of any one of
embodiments 186-247 with the exhaust gas.
[0562] Embodiment 252. A method of treating an exhaust gas,
comprising contacting the coated substrate of any one of
embodiments 186-247 with the exhaust gas, wherein the substrate is
housed within a catalytic converter configured to receive the
exhaust gas.
[0563] Embodiment 253. A coated substrate comprising: a
substrate;
[0564] a washcoat layer comprising oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles, the oxidative catalytically
active Nano-on-Nano-in-Micro (NNiM) particles comprising composite
nanoparticles embedded in a first micron-sized porous carrier, and
the composite nanoparticles comprising a first support nanoparticle
and an oxidative catalytic nanoparticle; a washcoat layer
comprising reductive catalytically active Nano-on-Nano-in-Micro
(NNiM) particles, the reductive catalytically active
Nano-on-Nano-in-Micro (NNiM) particles comprising composite
nanoparticles embedded in a second micron-sized porous carrier, and
the composite nanoparticles comprising a second support
nanoparticle and an oxidative catalytic nanoparticle; and a
washcoat layer comprising NO.sub.x trapping particles, and the
NO.sub.x trapping particles comprising micron-sized cerium
oxide.
[0565] Embodiment 254. The coated substrate of embodiment 253,
wherein the NO.sub.x trapping particles further comprise barium
oxide impregnated in the micron-sized cerium oxide.
[0566] Embodiment 255. The coated substrate of embodiment 253 or
254, wherein the NO.sub.x trapping particles further comprise
platinum and palladium impregnated in the micron-sized cerium
oxide.
[0567] Embodiment 256. The coated substrate of embodiment 254,
wherein the barium oxide is plasma-generated.
[0568] Embodiment 257. The coated substrate of embodiment 254,
wherein the barium oxide is impregnated in the micron-sized cerium
oxide by wet chemistry.
[0569] Embodiment 258. The coated substrate of embodiment 255,
wherein the platinum and palladium are plasma-generated.
[0570] Embodiment 259. The coated substrate of embodiment 255,
wherein the platinum and palladium are impregnated in the
micron-sized cerium oxide by wet chemistry.
[0571] Embodiment 260. The coated substrate of embodiment 253,
wherein the NO.sub.x trapping particles further comprise the
perovskite FeBaO.sub.3 impregnated in the micron-sized cerium
oxide.
[0572] Embodiment 261. The coated substrate of embodiment 253,
wherein the NO.sub.x trapping particles further comprise metal
oxides selected from the group consisting of samarium, zinc,
copper, iron, and silver impregnated in the micron-sized cerium
oxide.
[0573] Embodiment 262. The coated substrate of embodiment 260 or
261, wherein the NO.sub.x trapping particles are prepared by wet
chemistry.
[0574] Embodiment 263. The coated substrate of any one of
embodiments 260-263, wherein the NO.sub.x trapping particles
further comprise barium oxide impregnated in the micron-sized
cerium oxide.
[0575] Embodiment 264. The coated substrate of embodiment 253,
wherein the NO.sub.x trapping particles further comprise
micron-sized aluminum oxide particles.
[0576] Embodiment 265. The coated substrate of embodiment 264,
wherein the micron-sized aluminum oxide particles are
Nano-on-Nano-in-Micro (NNiM) particles.
[0577] Embodiment 266. The coated substrate of embodiment 265,
wherein the Nano-on-Nano-in-Micro (NNiM) particles comprise
platinum and/or palladium.
[0578] Embodiment 267. The coated substrate of embodiment 264,
wherein the Nano-on-Nano-in-Micro (NNiM) particles comprise a
non-platinum group metal.
[0579] Embodiment 268. The coated substrate of embodiment 267,
wherein the non-platinum group metal is selected from the group
consisting of tungsten, molybdenum, niobium, manganese, and
chromium.
[0580] Embodiment 269. The coated substrate of any one of
embodiments 264-268, further comprising barium oxide impregnated in
the micron-sized cerium oxide particles.
[0581] Embodiment 270. The coated substrate of any one of
embodiments 264-269, wherein the Nano-on-Nano-in-Micro (NNiM)
particles further comprise barium oxide impregnated in the NNiM
particles.
[0582] Embodiment 271. The coated substrate of embodiment 269 or
270, wherein the barium oxide is impregnated by wet chemistry.
[0583] Embodiment 272. The coated substrate of any one of
embodiment 253-271, wherein the composite nanoparticles are
plasma-generated.
[0584] Embodiment 273. The coated substrate of any one of
embodiments 253-272, wherein the oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles comprise at least one
platinum group metal.
[0585] Embodiment 274. The coated substrate of any one of
embodiments 253-273, wherein the oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles comprise platinum.
[0586] Embodiment 275. The coated substrate of any one of
embodiments 253-273, wherein the oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles comprise palladium.
[0587] Embodiment 276. The coated substrate of any one of
embodiments 253-275, wherein the oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles comprise platinum and
palladium.
[0588] Embodiment 277. The coated substrate of any one of
embodiments 253-276, wherein the first support nanoparticle
comprises aluminum oxide.
[0589] Embodiment 278. The coated substrate of any one of
embodiments 253-277, wherein the second support nanoparticle
comprises cerium oxide.
[0590] Embodiment 279. The coated substrate of any one of
embodiments 253-278, wherein the first micron-sized porous carrier
comprises aluminum oxide.
[0591] Embodiment 280. The coated substrate of any one of
embodiments 253-279, wherein the second micron-sized porous carrier
comprises cerium oxide.
[0592] Embodiment 281. The coated substrate of any one of
embodiments 253-280, wherein the reductive catalytically active
Nano-on-Nano-in-Micro (NNiM) particles comprise a platinum group
metal.
[0593] Embodiment 282. The coated substrate of embodiment 281,
wherein the platinum group metal is rhodium.
[0594] Embodiment 283. The coated substrate of any one of
embodiments 253-282, wherein the NO.sub.x trapping particles
further comprise zirconium oxide.
[0595] Embodiment 284. The coated substrate of any one of
embodiments 253-283, wherein the support nanoparticles have an
average diameter of about 10 nm to about 20 nm.
[0596] Embodiment 285. The coated substrate of any one of
embodiments 253-283, wherein the support nanoparticles have an
average diameter of about 1 nm to about 5 nm.
[0597] Embodiment 286. The coated substrate of any one of
embodiments 253-285, wherein the washcoat layer comprising
oxidative catalytically active Nano-on-Nano-in-Micro (NNiM)
particles further comprises metal oxide particles and boehmite
particles.
[0598] Embodiment 287. The coated substrate of embodiment 286,
wherein the metal oxide particles are aluminum oxide particles.
[0599] Embodiment 288. The coated substrate of embodiment 287,
wherein the oxidative catalytically active Nano-on-Nano-in-Micro
(NNiM) particles comprise 35% to 75% by weight of the combination
of the oxidative catalytically active Nano-on-Nano-in-Micro (NNiM)
particles, boehmite particles, and aluminum oxide particles.
[0600] Embodiment 289. The coated substrate of embodiment 287 or
288, wherein the aluminum oxide particles comprise 30% to 70% by
weight of the combination of the oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles, boehmite particles, and
aluminum oxide particles.
[0601] Embodiment 290. The coated substrate of any one of
embodiments 287-289, wherein the boehmite particles comprise 2% to
5% by weight of the combination of the oxidative catalytically
active Nano-on-Nano-in-Micro (NNiM) particles, boehmite particles,
and aluminum oxide particles.
[0602] Embodiment 291. The coated substrate of embodiment 287,
wherein the washcoat layer comprising oxidative catalytically
active Nano-on-Nano-in-Micro (NNiM) particles comprises 50% by
weight of the oxidative catalytically active Nano-on-Nano-in-Micro
(NNiM) particles, 3% by weight of the boehmite particles, and 47%
by weight of the aluminum oxide particles.
[0603] Embodiment 292. The coated substrate of any one of
embodiments 253-291, wherein the washcoat layer comprising
reductive catalytically active Nano-on-Nano-in-Micro (NNiM)
particles further comprises metal oxide particles and boehmite
particles.
[0604] Embodiment 293. The coated substrate of embodiment 292,
wherein the metal oxide particles are aluminum oxide particles.
[0605] Embodiment 294. The coated substrate of embodiment 293,
wherein the reductive catalytically active Nano-on-Nano-in-Micro
(NNiM) particles comprise 50% to 95% by weight of the combination
of the reductive catalytically active Nano-on-Nano-in-Micro (NNiM)
particles, aluminum oxide particles, and boehmite particles.
[0606] Embodiment 295. The coated substrate of embodiment 293 or
294, wherein the aluminum oxide particles comprise 5% to 40% by
weight of the combination of the reductive catalytically active
Nano-on-Nano-in-Micro (NNiM) particles, aluminum oxide particles,
and boehmite particles.
[0607] Embodiment 296. The coated substrate of any one of
embodiments 293-295, wherein the boehmite particles comprise 2% to
5% by weight of the combination of the reductive catalytically
active Nano-on-Nano-in-Micro (NNiM) particles, aluminum oxide
particles, and boehmite particles.
[0608] Embodiment 297. The coated substrate of embodiment 293,
wherein the washcoat layer comprising reductive catalytically
active Nano-on-Nano-in-Micro (NNiM) particles comprises 80% by
weight of the reductive catalytically active Nano-on-Nano-in-Micro
(NNiM) particles, 17% by weight of the aluminum oxide particles,
and 3% by weight of the boehmite particles.
[0609] Embodiment 298. The coated substrate of any one of
embodiments 253-297, wherein the washcoat layer comprising NO.sub.x
trapping particles further comprises Nano-on-Nano-in-Micro (NNiM)
particles and boehmite particles.
[0610] Embodiment 299. The coated substrate of embodiment 298,
wherein the Nano-on-Nano-in-Micro (NNiM) particles comprise a
platinum group metal.
[0611] Embodiment 300. The coated substrate of embodiment 299,
wherein the platinum group metal is selected from the group
consisting of ruthenium, platinum, and palladium.
[0612] Embodiment 301. The coated substrate of embodiment 298,
wherein the Nano-on-Nano-in-Micro (NNiM) particles comprise a
non-platinum group metal.
[0613] Embodiment 302. The coated substrate of embodiment 301,
wherein the non-platinum group metal is selected from the group
consisting of tungsten, molybdenum, niobium, manganese, and
chromium.
[0614] Embodiment 303. The coated substrate of any one of
embodiments 298-302, wherein the Nano-on-Nano-in-Micro (NNiM)
particles comprise 10% to 40% by weight of the combination of the
Nano-on-Nano-in-Micro (NNiM) particles, NO.sub.x trapping
particles, and boehmite particles.
[0615] Embodiment 304. The coated substrate of any one of
embodiments 298-303, wherein the NO.sub.x trapping particles
comprise 50% to 90% by weight of the combination of the
Nano-on-Nano-in-Micro (NNiM) particles, NO.sub.x trapping
particles, and boehmite particles.
[0616] Embodiment 305. The coated substrate of any one of
embodiments 298-304, wherein the boehmite particles comprise 2% to
5% by weight of the combination of the Nano-on-Nano-in-Micro (NNiM)
particles, NO.sub.x trapping particles, and boehmite particles.
[0617] Embodiment 306. The coated substrate of any one of
embodiments 298-305, wherein the washcoat layer comprising NO.sub.x
trapping particles comprises 73% by weight of the NO.sub.x trapping
particles, 23% by weight of the Nano-on-Nano-in-Micro (NNiM)
particles, and 4% by weight of the boehmite particles.
[0618] Embodiment 307. The coated substrate of any one of
embodiments 253-306, wherein the substrate comprises
cordierite.
[0619] Embodiment 308. The coated substrate of any one of
embodiments 253-307, wherein the substrate comprises a honeycomb
structure.
[0620] Embodiment 309. The coated substrate of any one of
embodiments 253-308, wherein the washcoat layer comprising
oxidative catalytically active Nano-on-Nano-in-Micro (NNiM)
particles has a thickness of 25 g/L to 150 g/L.
[0621] Embodiment 310. The coated substrate of any one of
embodiments 253-309, wherein the washcoat layer comprising
reductive catalytically active Nano-on-Nano-in-Micro (NNiM)
particles has a thickness of 25 g/L to 150 g/L.
[0622] Embodiment 311. The coated substrate of any one of
embodiments 253-310, wherein the washcoat layer comprising NO.sub.x
trapping particles has a thickness of 100 g/L to 400 g/L.
[0623] Embodiment 312. The coated substrate of any one of
embodiments 253-311, wherein the coated substrate has a platinum
group metal loading of 4 g/L or less and a light-off temperature
for carbon monoxide at least 5.degree. C. lower than the light-off
temperature of a substrate with the same platinum group metal
loading deposited by wet-chemistry methods.
[0624] Embodiment 313. The coated substrate of any one of
embodiments 253-312, said coated substrate having a platinum group
metal loading of about 3.0 g/L to about 5.5 g/L, wherein after
125,000 miles of operation in a vehicular catalytic converter, the
coated substrate has a light-off temperature for carbon monoxide at
least 5.degree. C. lower than a coated substrate prepared by
depositing platinum group metals by wet chemical methods having the
same platinum group metal loading after 125,000 miles of operation
in a vehicular catalytic converter.
[0625] Embodiment 314. The coated substrate of any one of
embodiments 253-313, said coated substrate having a platinum group
metal loading of about 3.0 g/L to about 5.5 g/L, wherein after
aging for 16 hours at 800.degree. C., the coated substrate has a
light-off temperature for carbon monoxide at least 5.degree. C.
lower than a coated substrate prepared by depositing platinum group
metals by wet chemical methods having the same platinum group metal
loading after aging for 16 hours at 800.degree. C.
[0626] Embodiment 315. A catalytic converter comprising a coated
substrate of any one of embodiments 253-314.
[0627] Embodiment 316. An exhaust treatment system comprising a
conduit for exhaust gas and a catalytic converter according to
embodiment 315.
[0628] Embodiment 317. A vehicle comprising a catalytic converter
according to embodiment 315.
[0629] Embodiment 318. A method of treating an exhaust gas,
comprising contacting the coated substrate of any one of
embodiments 253-314 with the exhaust gas.
[0630] Embodiment 319. A method of treating an exhaust gas,
comprising contacting the coated substrate of any one of
embodiments 253-314 with the exhaust gas, wherein the substrate is
housed within a catalytic converter configured to receive the
exhaust gas.
[0631] Embodiment 320. A coated substrate comprising: a substrate;
a washcoat layer comprising oxidative catalytically active
composite nanoparticles attached to a first micron-sized support
particle, the oxidative catalytically active composite
nanoparticles being plasma-generated and comprising a first support
nanoparticle and an oxidative catalytic nanoparticle; a washcoat
layer comprising reductive catalytically active composite
nanoparticles attached to a second micron-sized support particle,
the reductive catalytically active composite nanoparticles being
plasma-generated and comprising a second support nanoparticle and a
reductive catalytic nanoparticle; and a washcoat layer comprising
NO.sub.x trapping particles, and the NO.sub.x trapping particles
comprising micron-sized cerium oxide.
[0632] Embodiment 321. The coated substrate of embodiment 320,
wherein the NO.sub.x trapping particles further comprise barium
oxide impregnated in the micron-sized cerium oxide.
[0633] Embodiment 322. The coated substrate of embodiment 320 or
321, wherein the NO.sub.x trapping particles further comprise
platinum and palladium impregnated in the micron-sized cerium
oxide.
[0634] Embodiment 323. The coated substrate of embodiment 321,
wherein the barium oxide is plasma-generated.
[0635] Embodiment 324. The coated substrate of embodiment 321,
wherein the barium oxide is impregnated in the micron-sized cerium
oxide by wet chemistry.
[0636] Embodiment 325. The coated substrate of embodiment 322,
wherein the platinum and palladium are plasma-generated.
[0637] Embodiment 326. The coated substrate of embodiment 322,
wherein the platinum and palladium are impregnated in the
micron-sized cerium oxide by wet chemistry.
[0638] Embodiment 327. The coated substrate of embodiment 320,
wherein the NO.sub.x trapping particles further comprise the
perovskite FeBaO.sub.3 impregnated in the micron-sized cerium
oxide.
[0639] Embodiment 328. The coated substrate of embodiment 320,
wherein the NO.sub.x trapping particles further comprise metal
oxides selected from the group consisting of samarium, zinc,
copper, iron, and silver impregnated in the micron-sized cerium
oxide.
[0640] Embodiment 329. The coated substrate of embodiment 327 or
328, wherein the NO.sub.x trapping particles are prepared by wet
chemistry.
[0641] Embodiment 330. The coated substrate of any one of
embodiments 327-329, wherein the NO.sub.x trapping particles
further comprise barium oxide impregnated in the micron-sized
cerium oxide.
[0642] Embodiment 331. The coated substrate of embodiment 320,
wherein the NO.sub.x trapping particles further comprise
micron-sized aluminum oxide particles.
[0643] Embodiment 332. The coated substrate of embodiment 331,
wherein the micron-sized aluminum oxide particles are
Nano-on-Nano-on-micro (NNm) particles or Nano-on-Nano-in-Micro
(NNiM) particles.
[0644] Embodiment 333. The coated substrate of embodiment 332,
wherein the Nano-on-Nano-on-micro (NNm) particles or
Nano-on-Nano-in-Micro (NNiM) particles comprise platinum and/or
palladium.
[0645] Embodiment 334. The coated substrate of embodiment 331,
wherein the Nano-on-Nano-on-micro (NNm) particles or
Nano-on-Nano-in-Micro (NNiM) particles comprise a non-platinum
group metal.
[0646] Embodiment 335. The coated substrate of embodiment 334,
wherein the non-platinum group metal is selected from the group
consisting of tungsten, molybdenum, niobium, manganese, and
chromium.
[0647] Embodiment 336. The coated substrate of any one of
embodiments 331-335, further comprising barium oxide impregnated in
the micron-sized cerium oxide particles.
[0648] Embodiment 337. The coated substrate of any one of
embodiments 331-335, wherein the Nano-on-Nano-on-micro (NNm)
particles or Nano-on-Nano-in-Micro (NNiM) particles further
comprise barium oxide impregnated in the NNm or NNiM particles.
[0649] Embodiment 338. The coated substrate of embodiment 336 or
337, wherein the barium oxide is impregnated by wet chemistry.
[0650] Embodiment 339. The coated substrate of any one of
embodiment 320-338, wherein the oxidative catalytically active
composite nanoparticles attached to a first micron-sized support
particle comprise oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles.
[0651] Embodiment 340. The coated substrate of any one of
embodiments 320-338, wherein the oxidative catalytically active
composite nanoparticles attached to a first micron-sized support
particle comprise oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles.
[0652] Embodiment 341. The coated substrate of any one of
embodiments 320-340, wherein the oxidative catalytically active
composite nanoparticles comprise at least one platinum group
metal.
[0653] Embodiment 342. The coated substrate of any one of
embodiment 320-341, wherein the oxidative catalytically active
composite nanoparticles comprise platinum.
[0654] Embodiment 343. The coated substrate of any one of
embodiment 320-341, wherein the oxidative catalytically active
composite nanoparticles comprise palladium.
[0655] Embodiment 344. The coated substrate of any one of
embodiments 320-343, wherein the oxidative catalytically active
composite nanoparticles comprise platinum and palladium.
[0656] Embodiment 345. The coated substrate of any one of
embodiments 320-344, wherein the first support nanoparticle
comprises aluminum oxide.
[0657] Embodiment 346. The coated substrate of any one of
embodiments 320-345, wherein the second support nanoparticle
comprises cerium oxide.
[0658] Embodiment 347. The coated substrate of any one of
embodiments 320-346, wherein the first micron-sized support
particle comprises aluminum oxide.
[0659] Embodiment 348. The coated substrate of any one of
embodiments 320-347, wherein the second micron-sized support
particle comprises cerium oxide.
[0660] Embodiment 349. The coated substrate of any one of
embodiments 320-348, wherein the reductive catalytically active
composite nanoparticles comprise reductive catalytically active
Nano-on-Nano-on-micro (NNm) particles.
[0661] Embodiment 350. The coated substrate of embodiment 349,
wherein the reductive catalytically active Nano-on-Nano-on-micro
(NNm) particles comprise a platinum group metal.
[0662] Embodiment 351. The coated substrate of any one of
embodiments 320-348, wherein the reductive catalytically active
composite nanoparticles comprise reductive catalytically active
Nano-on-Nano-in-Micro (NNiM) particles.
[0663] Embodiment 352. The coated substrate of embodiment 351,
wherein the reductive catalytically active Nano-on-Nano-in-Micro
(NNiM) particles comprise a platinum group metal.
[0664] Embodiment 353. The coated substrate of embodiment 350 or
352, wherein the platinum group metal is rhodium.
[0665] Embodiment 354. The coated substrate of any one of
embodiments 320-353, wherein the NO.sub.x trapping particles
further comprise zirconium oxide.
[0666] Embodiment 355. The coated substrate of any one of
embodiments 320-354, wherein the support nanoparticles have an
average diameter of about 10 nm to about 20 nm.
[0667] Embodiment 356. The coated substrate of any one of
embodiments 320-354, wherein the support nanoparticles have an
average diameter of about 1 nm to about 5 nm.
[0668] Embodiment 357. The coated substrate of embodiment 339,
wherein the washcoat layer comprising oxidative catalytically
active Nano-on-Nano-on-micro (NNm) particles further comprises
metal oxide particles and boehmite particles.
[0669] Embodiment 358. The coated substrate of embodiment 357,
wherein the metal oxide particles are aluminum oxide particles.
[0670] Embodiment 359. The coated substrate of embodiment 358,
wherein the oxidative catalytically active Nano-on-Nano-on-micro
(NNm) particles comprise 35% to 75% by weight of the combination of
the oxidative catalytically active Nano-on-Nano-on-micro (NNm)
particles, boehmite particles, and aluminum oxide particles.
[0671] Embodiment 360. The coated substrate of embodiment 358 or
359, wherein the aluminum oxide particles comprise 30% to 70% by
weight of the combination of the oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles, boehmite particles, and
aluminum oxide particles.
[0672] Embodiment 361. The coated substrate of any one of
embodiments 358-360, wherein the boehmite particles comprise 2% to
5% by weight of the combination of the oxidative catalytically
active Nano-on-Nano-on-micro (NNm) particles, boehmite particles,
and aluminum oxide particles.
[0673] Embodiment 362. The coated substrate of embodiment 358,
wherein the washcoat layer comprising oxidative catalytically
active Nano-on-Nano-on-micro (NNm) particles comprises 50% by
weight of the oxidative catalytically active Nano-on-Nano-on-micro
(NNm) particles, 3% by weight of the boehmite particles, and 47% by
weight of the aluminum oxide particles.
[0674] Embodiment 363. The coated substrate of embodiment 340,
wherein the washcoat layer comprising oxidative catalytically
active Nano-on-Nano-in-Micro (NNiM) particles further comprises
metal oxide particles and boehmite particles.
[0675] Embodiment 364. The coated substrate of embodiment 363,
wherein the metal oxide particles are aluminum oxide particles.
[0676] Embodiment 365. The coated substrate of embodiment 364,
wherein the oxidative catalytically active Nano-on-Nano-in-Micro
(NNiM) particles comprise 35% to 75% by weight of the combination
of the oxidative catalytically active Nano-on-Nano-in-Micro (NNiM)
particles, boehmite particles, and aluminum oxide particles.
[0677] Embodiment 366. The coated substrate of embodiment 364 or
365, wherein the aluminum oxide particles comprise 30% to 70% by
weight of the combination of the oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles, boehmite particles, and
aluminum oxide particles.
[0678] Embodiment 367. The coated substrate of any one of
embodiments 364-366, wherein the boehmite particles comprise 2% to
5% by weight of the combination of the oxidative catalytically
active Nano-on-Nano-in-Micro (NNiM) particles, boehmite particles,
and aluminum oxide particles.
[0679] Embodiment 368. The coated substrate of embodiment 364,
wherein the washcoat layer comprising oxidative catalytically
active Nano-on-Nano-in-Micro (NNiM) particles comprises 50% by
weight of the oxidative catalytically active Nano-on-Nano-in-Micro
(NNiM) particles, 3% by weight of the boehmite particles, and 47%
by weight of the aluminum oxide particles.
[0680] Embodiment 369. The coated substrate of embodiment 349,
wherein the washcoat layer comprising reductive catalytically
active Nano-on-Nano-on-micro (NNm) particles further comprises
metal oxide particles and boehmite particles.
[0681] Embodiment 370. The coated substrate of embodiment 369,
wherein the metal oxide particles are aluminum oxide particles.
[0682] Embodiment 371. The coated substrate of embodiment 370,
wherein the reductive catalytically active Nano-on-Nano-on-micro
(NNm) particles comprise 50% to 95% by weight of the combination of
the reductive catalytically active Nano-on-Nano-on-micro (NNm)
particles, aluminum oxide particles, and boehmite particles.
[0683] Embodiment 372. The coated substrate of embodiment 370 or
371, wherein the aluminum oxide particles comprise 5% to 40% by
weight of the combination of the reductive catalytically active
Nano-on-Nano-on-micro (NNm) particles, aluminum oxide particles,
and boehmite particles.
[0684] Embodiment 373. The coated substrate of any one of
embodiments 370-372, wherein the boehmite particles comprise 2% to
5% by weight of the combination of the reductive catalytically
active Nano-on-Nano-on-micro (NNm) particles, aluminum oxide
particles, and boehmite particles.
[0685] Embodiment 374. The coated substrate of embodiment 370,
wherein the washcoat layer comprising reductive catalytically
active Nano-on-Nano-on-micro (NNm) particles comprises 80% by
weight of the reductive catalytically active Nano-on-Nano-on-micro
(NNm) particles, 17% by weight of the aluminum oxide particles, and
3% by weight of the boehmite particles.
[0686] Embodiment 375. The coated substrate of embodiment 351,
wherein the washcoat layer comprising reductive catalytically
active Nano-on-Nano-in-Micro (NNiM) particles further comprises
metal oxide particles and boehmite particles.
[0687] Embodiment 376. The coated substrate of embodiment 375,
wherein the metal oxide particles are aluminum oxide particles.
[0688] Embodiment 377. The coated substrate of embodiment 376,
wherein the reductive catalytically active Nano-on-Nano-in-Micro
(NNiM) particles comprise 50% to 95% by weight of the combination
of the reductive catalytically active Nano-on-Nano-in-Micro (NNiM)
particles, aluminum oxide particles, and boehmite particles.
[0689] Embodiment 378. The coated substrate of embodiment 376 or
377, wherein the aluminum oxide particles comprise 5% to 40% by
weight of the combination of the reductive catalytically active
Nano-on-Nano-in-Micro (NNiM) particles, aluminum oxide particles,
and boehmite particles.
[0690] Embodiment 379. The coated substrate of any one of
embodiments 376-378, wherein the boehmite particles comprise 2% to
5% by weight of the combination of the reductive catalytically
active Nano-on-Nano-in-Micro (NNiM) particles, aluminum oxide
particles, and boehmite particles.
[0691] Embodiment 380. The coated substrate of embodiment 376,
wherein the washcoat layer comprising reductive catalytically
active Nano-on-Nano-in-Micro (NNiM) particles comprises 80% by
weight of the reductive catalytically active Nano-on-Nano-in-Micro
(NNiM) particles, 17% by weight of the aluminum oxide particles,
and 3% by weight of the boehmite particles.
[0692] Embodiment 381. The coated substrate of any one of
embodiments 320-380, wherein the washcoat layer comprising NO.sub.x
trapping particles further comprises Nano-on-Nano-on-micro (NNm)
particles and boehmite particles.
[0693] Embodiment 382. The coated substrate of embodiment 381,
wherein the Nano-on-Nano-on-micro (NNm) particles comprise at least
one platinum group metal.
[0694] Embodiment 383. The coated substrate of embodiment 382,
wherein the platinum group metal is selected from the group
consisting of ruthenium, platinum, and palladium.
[0695] Embodiment 384. The coated substrate of embodiment 381,
wherein the Nano-on-Nano-on-micro (NNm) particles comprise a
non-platinum group metal.
[0696] Embodiment 385. The coated substrate of embodiment 384,
wherein the non-platinum group metal is selected from the group
consisting of tungsten, molybdenum, niobium, manganese, and
chromium.
[0697] Embodiment 386. The coated substrate of any one of
embodiments 381-385, wherein the Nano-on-Nano-on-micro (NNm)
particles comprise 10% to 40% by weight of the combination of the
Nano-on-Nano-on-micro (NNm) particles, NO.sub.x trapping particles,
and boehmite particles.
[0698] Embodiment 387. The coated substrate of any one of
embodiments 381-386, wherein the NO.sub.x trapping particles
comprise 50% to 90% by weight of the combination of the
Nano-on-Nano-on-micro (NNm) particles, NO.sub.x trapping particles,
and boehmite particles.
[0699] Embodiment 388. The coated substrate of any one of
embodiments 381-387, wherein the boehmite particles comprise 2% to
5% by weight of the combination of the Nano-on-Nano-on-micro (NNm)
particles, NO.sub.x trapping particles, and boehmite particles.
[0700] Embodiment 389. The coated substrate of any one of
embodiments 381-388, wherein the washcoat layer comprising NO.sub.x
trapping particles comprises 73% by weight of the NO.sub.x trapping
particles, 23% by weight of the Nano-on-Nano-on-micro (NNm)
particles, and 4% by weight of the boehmite particles.
[0701] Embodiment 390. The coated substrate of any one of
embodiments 320-389, wherein the substrate comprises
cordierite.
[0702] Embodiment 391. The coated substrate of any one of
embodiments 320-390, wherein the substrate comprises a honeycomb
structure.
[0703] Embodiment 392. The coated substrate of embodiment 339,
wherein the washcoat layer comprising oxidative catalytically
active Nano-on-Nano-on-micro (NNm) particles has a thickness of 25
g/L to 150 g/L.
[0704] Embodiment 393. The coated substrate of embodiment 340,
wherein the washcoat layer comprising oxidative catalytically
active Nano-on-Nano-in-Micro (NNiM) particles has a thickness of 25
g/L to 150 g/L.
[0705] Embodiment 394. The coated substrate of embodiment 349,
wherein the washcoat layer comprising reductive catalytically
active Nano-on-Nano-on-micro (NNm) particles has a thickness of 100
g/L to 400 g/L.
[0706] Embodiment 395. The coated substrate of embodiment 351,
wherein the washcoat layer comprising reductive catalytically
active Nano-on-Nano-in-Micro (NNiM) particles has a thickness of
100 g/L to 400 g/L.
[0707] Embodiment 396. The coated substrate of any one of
embodiments 320-395, wherein the washcoat layer comprising NO.sub.x
trapping particles particles has a thickness of 100 g/L to 400
g/L.
[0708] Embodiment 397. The coated substrate of any one of
embodiments 320-396, wherein the coated substrate has a platinum
group metal loading of 4 g/L or less and a light-off temperature
for carbon monoxide at least 5.degree. C. lower than the light-off
temperature of a substrate with the same platinum group metal
loading deposited by wet-chemistry methods.
[0709] Embodiment 398. The coated substrate of any one of
embodiments 320-397, said coated substrate having a platinum group
metal loading of about 3.0 g/L to about 5.5 g/L, wherein after
125,000 miles of operation in a vehicular catalytic converter, the
coated substrate has a light-off temperature for carbon monoxide at
least 5.degree. C. lower than a coated substrate prepared by
depositing platinum group metals by wet chemical methods having the
same platinum group metal loading after 125,000 miles of operation
in a vehicular catalytic converter.
[0710] Embodiment 399. The coated substrate of any one of
embodiments 320-398, said coated substrate having a platinum group
metal loading of about 3.0 g/L to about 5.5 g/L, wherein after
aging for 16 hours at 800.degree. C., the coated substrate has a
light-off temperature for carbon monoxide at least 5.degree. C.
lower than a coated substrate prepared by depositing platinum group
metals by wet chemical methods having the same platinum group metal
loading after aging for 16 hours at 800.degree. C.
[0711] Embodiment 400. A catalytic converter comprising a coated
substrate of any one of embodiments 320-399.
[0712] Embodiment 401. An exhaust treatment system comprising a
conduit for exhaust gas and a catalytic converter according to
embodiment 400.
[0713] Embodiment 402. A vehicle comprising a catalytic converter
according to embodiment 400.
[0714] Embodiment 403. A method of treating an exhaust gas,
comprising contacting the coated substrate of any one of
embodiments 320-399 with the exhaust gas.
[0715] Embodiment 404. A method of treating an exhaust gas,
comprising contacting the coated substrate of any one of
embodiments 320-399 with the exhaust gas, wherein the substrate is
housed within a catalytic converter configured to receive the
exhaust gas.
[0716] Embodiment 405. A method of forming a coated substrate, the
method comprising: a) coating a substrate with a washcoat
composition comprising oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles, the oxidative catalytically
active Nano-on-Nano-on-micro (NNm) particles comprising composite
nanoparticles bonded to a first micron-sized carrier particle, and
the composite nanoparticles comprising a first support nanoparticle
and an oxidative catalytic nanoparticle; and b) coating the
substrate with a washcoat composition comprising reductive
catalytically active Nano-on-Nano-on-micro (NNm) particles and
NO.sub.x trapping particles, the reductive catalytically active
Nano-on-Nano-on-micro (NNm) particles comprising composite
nanoparticles bonded to second micron-sized carrier particle, and
the composite nanoparticles comprising a second support
nanoparticle and a reductive catalytic nanoparticle, and the
NO.sub.x trapping particles comprising micron-sized cerium
oxide.
[0717] Embodiment 406. The method of embodiment 405, wherein the
NO.sub.x trapping particles further comprise barium oxide
impregnated in the micron-sized cerium oxide.
[0718] Embodiment 407. The method of embodiment 405 or 406, wherein
the NO.sub.x trapping particles further comprise platinum and
palladium impregnated in the micron-sized cerium oxide.
[0719] Embodiment 408. The method of embodiment 406, wherein the
barium oxide is plasma-generated.
[0720] Embodiment 409. The method of embodiment 406, wherein the
barium oxide is impregnated in the micron-sized cerium oxide by wet
chemistry.
[0721] Embodiment 410. The method of embodiment 407, wherein the
platinum and palladium are plasma-generated.
[0722] Embodiment 411. The method of embodiment 407, wherein the
platinum and palladium are impregnated in the micron-sized cerium
oxide by wet chemistry.
[0723] Embodiment 412. The method of embodiment 405, wherein the
NO.sub.x trapping particles further comprise the perovskite
FeBaO.sub.3 impregnated in the micron-sized cerium oxide.
[0724] Embodiment 413. The method of embodiment 405, wherein the
NO.sub.x trapping particles further comprise metal oxides selected
from the group consisting of samarium, zinc, copper, iron, and
silver impregnated in the micron-sized cerium oxide.
[0725] Embodiment 414. The method of embodiment 412 or 413, wherein
the NO.sub.x trapping particles are prepared by wet chemistry.
[0726] Embodiment 415. The method of any one of embodiments
412-414, wherein the NO.sub.x trapping particles further comprise
barium oxide impregnated in the micron-sized cerium oxide.
[0727] Embodiment 416. The method of embodiment 405, wherein the
NO.sub.x trapping particles further comprise micron-sized aluminum
oxide particles.
[0728] Embodiment 417. The method of embodiment 416, wherein the
micron-sized aluminum oxide particles are Nano-on-Nano-on-micro
(NNm) particles.
[0729] Embodiment 418. The method of embodiment 417, wherein the
Nano-on-Nano-on-micro (NNm) particles comprise platinum and/or
palladium.
[0730] Embodiment 419. The method of embodiment 416, wherein the
Nano-on-Nano-on-micro (NNm) particles comprise a non-platinum group
metal.
[0731] Embodiment 420. The method of embodiment 419, wherein the
non-platinum group metal is selected from the group consisting of
tungsten, molybdenum, niobium, manganese, and chromium.
[0732] Embodiment 421. The method of any one of embodiments
416-420, further comprising barium oxide impregnated in the
micron-sized cerium oxide particles.
[0733] Embodiment 422. The method of any one of embodiments
416-421, wherein the Nano-on-Nano-on-micro (NNm) particles further
comprise barium oxide impregnated in the NNm particles.
[0734] Embodiment 423. The method of embodiment 421 or 422, wherein
the barium oxide is impregnated by wet chemistry.
[0735] Embodiment 424. The method of any one of embodiments
405-423, wherein the composite nanoparticles are
plasma-generated.
[0736] Embodiment 425. The method of any one of embodiments
405-424, wherein the oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles comprise at least one
platinum group metal.
[0737] Embodiment 426. The method of any one of embodiments
405-425, wherein the oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles comprise platinum.
[0738] Embodiment 427. The method of any one of embodiments
405-425, wherein the oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles comprise palladium.
[0739] Embodiment 428. The method of any one of embodiments
405-427, wherein the oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles comprise platinum and
palladium.
[0740] Embodiment 429. The method of any one of embodiments
405-428, wherein the first support nanoparticle comprises aluminum
oxide.
[0741] Embodiment 430. The method of any one of embodiments
405-429, wherein the second support nanoparticle comprises cerium
oxide.
[0742] Embodiment 431. The method of any one of embodiments
405-430, wherein the first micron-sized carrier particle comprises
aluminum oxide.
[0743] Embodiment 432. The method of any one of embodiments
405-431, wherein the second micron-sized carrier particle comprises
cerium oxide.
[0744] Embodiment 433. The method of any one of embodiments
405-432, wherein the reductive catalytically active
Nano-on-Nano-on-micro (NNm) particles comprise a platinum group
metal.
[0745] Embodiment 434. The method of embodiment 433, wherein the
platinum group metal is rhodium.
[0746] Embodiment 435. The method of any one of embodiments
405-434, wherein the NO.sub.x trapping particles comprising
micron-sized cerium oxide further comprise zirconium oxide.
[0747] Embodiment 436. The method of any one of embodiments
405-435, wherein the support nanoparticles have an average diameter
of about 10 nm to about 20 nm.
[0748] Embodiment 437. The method of any one of embodiments
405-435, wherein the support nanoparticles have an average diameter
of about 1 nm to about 5 nm.
[0749] Embodiment 438. The method of any one of embodiments
405-437, wherein the washcoat layer comprising oxidative
catalytically active Nano-on-Nano-on-micro (NNm) particles further
comprises metal oxide particles and boehmite particles.
[0750] Embodiment 439. The method of embodiment 438, wherein the
metal oxide particles are aluminum oxide particles.
[0751] Embodiment 440. The method of embodiment 439, wherein the
oxidative catalytically active Nano-on-Nano-on-micro (NNm)
particles comprise 35% to 75% by weight of the combination of the
oxidative catalytically active Nano-on-Nano-on-micro (NNm)
particles, boehmite particles, and aluminum oxide particles.
[0752] Embodiment 441. The method of embodiment 439 or 440, wherein
the aluminum oxide particles comprise 30% to 70% by weight of the
combination of the oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles, boehmite particles, and
aluminum oxide particles.
[0753] Embodiment 442. The method of any one of embodiments
439-441, wherein the boehmite particles comprise 2% to 5% by weight
of the combination of the oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles, boehmite particles, and
aluminum oxide particles.
[0754] Embodiment 443. The method of embodiment 439, wherein the
washcoat layer comprising oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles comprises 50% by weight of
the oxidative catalytically active Nano-on-Nano-on-micro (NNm)
particles, 3% by weight of the boehmite particles, and 47% by
weight of the aluminum oxide particles.
[0755] Embodiment 444. The method of any one of embodiments
405-443, wherein the washcoat layer comprising reductive
catalytically active Nano-on-Nano-on-micro (NNm) particles and
NO.sub.x trapping particles further comprises boehmite.
[0756] Embodiment 445. The method of embodiment 444, wherein the
reductive catalytically active Nano-on-Nano-on-micro (NNm)
particles comprise 3% to 40% by weight of the combination of the
reductive catalytically active Nano-on-Nano-on-micro (NNm)
particles, NO.sub.x trapping particles, and boehmite particles.
[0757] Embodiment 446. The method of embodiment 444 or 445, wherein
the NO.sub.x trapping particles comprise 30% to 98% by weight of
the combination of the reductive catalytically active
Nano-on-Nano-on-micro (NNm) particles, NO.sub.x trapping particles,
and boehmite particles.
[0758] Embodiment 447. The method of any one of embodiments
444-446, wherein the boehmite particles comprise 1% to 5% by weight
of the combination of the reductive catalytically active
Nano-on-Nano-on-micro (NNm) particles, NO.sub.x trapping particles,
and boehmite particles.
[0759] Embodiment 448. The method of embodiment 444, wherein the
washcoat layer comprising reductive catalytically active
Nano-on-Nano-on-micro (NNm) particles and NO.sub.x trapping
particles comprises 15% by weight of the reductive catalytically
active Nano-on-Nano-on-micro (NNm) particles, 83% by weight of the
NO.sub.x trapping particles, and 2% by weight of the boehmite
particles.
[0760] Embodiment 449. The method of any one of embodiments
405-448, wherein the substrate comprises cordierite.
[0761] Embodiment 450. The method of any one of embodiments
405-449, wherein the substrate comprises a honeycomb structure.
[0762] Embodiment 451. The method of any one of embodiments
405-450, wherein the washcoat layer comprising oxidative
catalytically active Nano-on-Nano-on-micro (NNm) particles has a
thickness of 25 g/L to 150 g/L.
[0763] Embodiment 452. The method of any one of embodiments
405-451, wherein the washcoat layer comprising reductive
catalytically active Nano-on-Nano-on-micro (NNm) particles and
NO.sub.x trapping particles has a thickness of 100 g/L to 400
g/L.
[0764] Embodiment 453. The method of any one of embodiments
405-452, wherein the coated substrate has a platinum group metal
loading of 4 g/L or less and a light-off temperature for carbon
monoxide at least 5.degree. C. lower than the light-off temperature
of a substrate with the same platinum group metal loading deposited
by wet-chemistry methods.
[0765] Embodiment 454. The method of any one of embodiments
405-453, said coated substrate having a platinum group metal
loading of about 3.0 g/L to about 5.5 g/L, wherein after 125,000
miles of operation in a vehicular catalytic converter, the coated
substrate has a light-off temperature for carbon monoxide at least
5.degree. C. lower than a coated substrate prepared by depositing
platinum group metals by wet chemical methods having the same
platinum group metal loading after 125,000 miles of operation in a
vehicular catalytic converter.
[0766] Embodiment 455. The method of any one of embodiments 1-50,
said coated substrate having a platinum group metal loading of
about 3.0 g/L to about 5.5 g/L, wherein after aging for 16 hours at
800.degree. C., the coated substrate has a light-off temperature
for carbon monoxide at least 5.degree. C. lower than a coated
substrate prepared by depositing platinum group metals by wet
chemical methods having the same platinum group metal loading after
aging for 16 hours at 800.degree. C.
[0767] Embodiment 456. A method of forming a coated substrate, the
method comprising: a) coating a substrate with a washcoat
composition comprising oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles, the oxidative catalytically
active Nano-on-Nano-in-Micro (NNiM) particles comprising composite
nanoparticles embedded in a first micron-sized porous carrier, and
the composite nanoparticles comprising a first support nanoparticle
and an oxidative catalytic nanoparticle; and b) coating a substrate
with a washcoat composition comprising reductive catalytically
active Nano-on-Nano-in-Micro (NNiM) particles and NO.sub.x trapping
particles, the reductive catalytically active Nano-on-Nano-in-Micro
(NNiM) particles comprising composite nanoparticles embedded in a
second micron-sized porous carrier, and the composite nanoparticles
comprising a second support nanoparticle and an oxidative catalytic
nanoparticle, and the NO.sub.x trapping particles comprising
micron-sized cerium oxide.
[0768] Embodiment 457. The method of embodiment 456, wherein the
NO.sub.x trapping particles further comprise barium oxide
impregnated in the micron-sized cerium oxide.
[0769] Embodiment 458. The method of embodiment 456 or 457, wherein
the NO.sub.x trapping particles further comprise platinum and
palladium impregnated in the micron-sized cerium oxide.
[0770] Embodiment 459. The method of embodiment 457, wherein the
barium oxide is plasma-generated.
[0771] Embodiment 460. The method of embodiment 457, wherein the
barium oxide is impregnated in the micron-sized cerium oxide by wet
chemistry.
[0772] Embodiment 461. The method of embodiment 458, wherein the
platinum and palladium are plasma-generated.
[0773] Embodiment 462. The method of embodiment 458, wherein the
platinum and palladium are impregnated in the micron-sized cerium
oxide by wet chemistry.
[0774] Embodiment 463. The method of embodiment 456, wherein the
NO.sub.x trapping particles further comprise the perovskite
FeBaO.sub.3 impregnated in the micron-sized cerium oxide.
[0775] Embodiment 464. The method of embodiment 456, wherein the
NO.sub.x trapping particles further comprise metal oxides selected
from the group consisting of samarium, zinc, copper, iron, and
silver impregnated in the micron-sized cerium oxide.
[0776] Embodiment 465. The method of embodiment 463 or 464, wherein
the NO.sub.x trapping particles are prepared by wet chemistry.
[0777] Embodiment 466. The method of any one of embodiments
463-465, wherein the NO.sub.x trapping particles further comprise
barium oxide impregnated in the micron-sized cerium oxide.
[0778] Embodiment 467. The method of embodiment 456, wherein the
NO.sub.x trapping particles further comprise micron-sized aluminum
oxide particles.
[0779] Embodiment 468. The method of embodiment 467, wherein the
micron-sized aluminum oxide particles are Nano-on-Nano-in-Micro
(NNiM) particles.
[0780] Embodiment 469. The method of embodiment 468, wherein the
Nano-on-Nano-in-Micro (NNiM) particles comprise platinum and/or
palladium.
[0781] Embodiment 470. The method of embodiment 467, wherein the
Nano-on-Nano-in-Micro (NNiM) particles comprise a non-platinum
group metal.
[0782] Embodiment 471. The method of embodiment 470, wherein the
non-platinum group metal is selected from the group consisting of
tungsten, molybdenum, niobium, manganese, and chromium.
[0783] Embodiment 472. The method of any one of embodiments
467-471, further comprising barium oxide impregnated in the
micron-sized cerium oxide particles.
[0784] Embodiment 473. The method of any one of embodiments
467-472, wherein the Nano-on-Nano-in-Micro (NNiM) particles further
comprise barium oxide impregnated in the NNiM particles.
[0785] Embodiment 474. The method of embodiment 472 or 473, wherein
the barium oxide is impregnated by wet chemistry.
[0786] Embodiment 475. The method of any one of embodiments
456-474, wherein the composite nanoparticles are
plasma-generated.
[0787] Embodiment 476. The method of any one of embodiments
456-475, wherein the oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles comprise at least one
platinum group metal.
[0788] Embodiment 477. The method of any one of embodiments
456-476, wherein the oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles comprise platinum.
[0789] Embodiment 478. The method of any one of embodiments
456-476, wherein the oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles comprise palladium.
[0790] Embodiment 479. The method of any one of embodiments
456-478, wherein the oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles comprise platinum and
palladium.
[0791] Embodiment 480. The method of any one of embodiments
456-479, wherein the first support nanoparticle comprises aluminum
oxide.
[0792] Embodiment 481. The method of any one of embodiments
456-480, wherein the second support nanoparticle comprises cerium
oxide.
[0793] Embodiment 482. The method of any one of embodiments
456-481, wherein the first micron-sized carrier particle comprises
aluminum oxide.
[0794] Embodiment 483. The method of any one of embodiments
456-482, wherein the second micron-sized carrier particle comprises
cerium oxide.
[0795] Embodiment 484. The method of any one of embodiments
456-483, wherein the reductive catalytically active
Nano-on-Nano-in-Micro (NNiM) particles comprise a platinum group
metal.
[0796] Embodiment 485. The method of embodiment 484, wherein the
platinum group metal is rhodium.
[0797] Embodiment 486. The method of any one of embodiments
456-485, wherein the NO.sub.x trapping particles comprising
micron-sized cerium oxide further comprise zirconium oxide.
[0798] Embodiment 487. The method of any one of embodiments
456-486, wherein the support nanoparticles have an average diameter
of about 10 nm to about 20 nm.
[0799] Embodiment 488. The method of any one of embodiments
456-486, wherein the support nanoparticles have an average diameter
of about 1 nm to about 5 nm.
[0800] Embodiment 489. The method of any one of embodiments
456-488, wherein the washcoat layer comprising oxidative
catalytically active Nano-on-Nano-in-Micro (NNiM) particles further
comprises metal oxide particles and boehmite particles.
[0801] Embodiment 490. The method of embodiment 489, wherein the
metal oxide particles are aluminum oxide particles.
[0802] Embodiment 491. The method of embodiment 490, wherein the
oxidative catalytically active Nano-on-Nano-in-Micro (NNiM)
particles comprise 35% to 75% by weight of the combination of the
oxidative catalytically active Nano-on-Nano-in-Micro (NNiM)
particles, boehmite particles, and aluminum oxide particles.
[0803] Embodiment 492. The method of embodiment 490 or 491, wherein
the aluminum oxide particles comprise 30% to 70% by weight of the
combination of the oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles, boehmite particles, and
aluminum oxide particles.
[0804] Embodiment 493. The method of any one of embodiments
490-492, wherein the boehmite particles comprise 2% to 5% by weight
of the combination of the oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles, boehmite particles, and
aluminum oxide particles.
[0805] Embodiment 494. The method of embodiment 490, wherein the
washcoat layer comprising oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles comprises 50% by weight of
the oxidative catalytically active Nano-on-Nano-in-Micro (NNiM)
particles, 3% by weight of the boehmite particles, and 47% by
weight of the aluminum oxide particles.
[0806] Embodiment 495. The method of any one of embodiments
456-494, wherein the washcoat layer comprising reductive
catalytically active Nano-on-Nano-in-Micro (NNiM) particles and
NO.sub.x trapping particles further comprises boehmite.
[0807] Embodiment 496. The method of embodiment 495, wherein the
reductive catalytically active Nano-on-Nano-in-Micro (NNiM)
particles comprise 3% to 40% by weight of the combination of the
reductive catalytically active Nano-on-Nano-in-Micro (NNiM)
particles, NO.sub.x trapping particles, and boehmite particles.
[0808] Embodiment 497. The method of embodiment 495 or 496, wherein
the NO.sub.x trapping particles comprise 30% to 98% by weight of
the combination of the reductive catalytically active
Nano-on-Nano-in-Micro (NNiM) particles, NO.sub.x trapping
particles, and boehmite particles.
[0809] Embodiment 498. The method of any one of embodiments
495-497, wherein the boehmite particles comprise 1% to 5% by weight
of the combination of the reductive catalytically active
Nano-on-Nano-in-Micro (NNiM) particles, NO.sub.x trapping
particles, and boehmite particles.
[0810] Embodiment 499. The method of embodiment 495, wherein the
washcoat layer comprising reductive catalytically active
Nano-on-Nano-in-Micro (NNiM) particles and NO.sub.x trapping
particles comprises 15% by weight of the reductive catalytically
active Nano-on-Nano-in-Micro (NNiM) particles, 83% by weight of the
NO.sub.x trapping particles, and 2% by weight of the boehmite
particles.
[0811] Embodiment 500. The method of any one of embodiments
456-499, wherein the substrate comprises cordierite.
[0812] Embodiment 501. The method of any one of embodiments
456-500, wherein the substrate comprises a honeycomb structure.
[0813] Embodiment 502. The method of any one of embodiments
456-501, wherein the washcoat layer comprising oxidative
catalytically active Nano-on-Nano-in-Micro (NNiM) particles has a
thickness of 25 g/L to 150 g/L.
[0814] Embodiment 503. The method of any one of embodiments
456-502, wherein the washcoat layer comprising reductive
catalytically active Nano-on-Nano-in-Micro (NNiM) particles and
NO.sub.x trapping particles has a thickness of 100 g/L to 400
g/L.
[0815] Embodiment 504. The method of any one of embodiments
456-503, wherein the coated substrate has a platinum group metal
loading of 4 g/L or less and a light-off temperature for carbon
monoxide at least 5.degree. C. lower than the light-off temperature
of a substrate with the same platinum group metal loading deposited
by wet-chemistry methods.
[0816] Embodiment 505. The method of any one of embodiments
456-504, said coated substrate having a platinum group metal
loading of about 3.0 g/L to about 5.5 g/L, wherein after 125,000
miles of operation in a vehicular catalytic converter, the coated
substrate has a light-off temperature for carbon monoxide at least
5.degree. C. lower than a coated substrate prepared by depositing
platinum group metals by wet chemical methods having the same
platinum group metal loading after 125,000 miles of operation in a
vehicular catalytic converter.
[0817] Embodiment 506. The method of any one of embodiments
456-505, said coated substrate having a platinum group metal
loading of about 3.0 g/L to about 5.5 g/L, wherein after aging for
16 hours at 800.degree. C., the coated substrate has a light-off
temperature for carbon monoxide at least 5.degree. C. lower than a
coated substrate prepared by depositing platinum group metals by
wet chemical methods having the same platinum group metal loading
after aging for 16 hours at 800.degree. C.
[0818] Embodiment 507. A method of forming a coated substrate, the
method comprising: a) coating a substrate with a washcoat
composition comprising oxidative catalytically active composite
nanoparticles attached to a first micron-sized support particle,
the oxidative catalytically active composite nanoparticles being
plasma-generated and comprising a first support nanoparticle and an
oxidative catalytic nanoparticle; and b) coating a substrate with a
washcoat composition comprising NO.sub.x trapping particles and
reductive catalytically active composite nanoparticles attached to
a second micron-sized support particle, the reductive catalytically
active composite nanoparticles being plasma-generated and
comprising a second support nanoparticle and a reductive catalytic
nanoparticle, and the NO.sub.x trapping particles comprising
micron-sized cerium oxide.
[0819] Embodiment 508. The method of embodiment 507, wherein the
NO.sub.x trapping particles further comprise barium oxide
impregnated in the micron-sized cerium oxide.
[0820] Embodiment 509. The method of embodiment 507 or 508, wherein
the NO.sub.x trapping particles further comprise platinum and
palladium impregnated in the micron-sized cerium oxide.
[0821] Embodiment 510. The method of embodiment 508, wherein the
barium oxide is plasma-generated.
[0822] Embodiment 511. The method of embodiment 508, wherein the
barium oxide is impregnated in the micron-sized cerium oxide by wet
chemistry.
[0823] Embodiment 512. The method of embodiment 509, wherein the
platinum and palladium are plasma-generated.
[0824] Embodiment 513. The method of embodiment 509, wherein the
platinum and palladium are impregnated in the micron-sized cerium
oxide by wet chemistry.
[0825] Embodiment 514. The method of embodiment 507, wherein the
NO.sub.x trapping particles further comprise the perovskite
FeBaO.sub.3 impregnated in the micron-sized cerium oxide.
[0826] Embodiment 515. The method of embodiment 507, wherein the
NO.sub.x trapping particles further comprise metal oxides selected
from the group consisting of samarium, zinc, copper, iron, and
silver impregnated in the micron-sized cerium oxide.
[0827] Embodiment 516. The method of embodiment 514 or 515, wherein
the NO.sub.x trapping particles are prepared by wet chemistry.
[0828] Embodiment 517. The method of any one of embodiments
514-516, wherein the NO.sub.x trapping particles further comprise
barium oxide impregnated in the micron-sized cerium oxide.
[0829] Embodiment 518. The method of embodiment 507, wherein the
NO.sub.x trapping particles further comprise micron-sized aluminum
oxide particles.
[0830] Embodiment 519. The method of embodiment 518, wherein the
micron-sized aluminum oxide particles are Nano-on-Nano-on-micro
(NNm) particles or Nano-on-Nano-in-Micro (NNiM) particles.
[0831] Embodiment 520. The method of embodiment 519, wherein the
Nano-on-Nano-on-micro (NNm) particles or Nano-on-Nano-in-Micro
(NNiM) particles comprise platinum and/or palladium.
[0832] Embodiment 521. The method of embodiment 518, wherein the
Nano-on-Nano-on-micro (NNm) particles or Nano-on-Nano-in-Micro
(NNiM) particles comprise a non-platinum group metal.
[0833] Embodiment 522. The method of embodiment 521, wherein the
non-platinum group metal is selected from the group consisting of
tungsten, molybdenum, niobium, manganese, and chromium.
[0834] Embodiment 523. The method of any one of embodiments
518-522, further comprising barium oxide impregnated in the
micron-sized cerium oxide particles.
[0835] Embodiment 524. The method of any one of embodiments
518-522, wherein the Nano-on-Nano-on-micro (NNm) particles or
Nano-on-Nano-in-Micro (NNiM) particles further comprise barium
oxide impregnated in the NNm or NNiM particles.
[0836] Embodiment 525. The method of embodiment 523 or 524, wherein
the barium oxide is impregnated by wet chemistry.
[0837] Embodiment 526. The method of any one of embodiments
507-525, wherein the oxidative catalytically active composite
nanoparticles attached to a first micron-sized support particle
comprise oxidative catalytically active Nano-on-Nano-on-micro (NNm)
particles.
[0838] Embodiment 527. The method of any one of embodiments
507-525, wherein the oxidative catalytically active composite
nanoparticles attached to a first micron-sized support particle
comprise oxidative catalytically active Nano-on-Nano-in-Micro
(NNiM) particles.
[0839] Embodiment 528. The method of any one of embodiments
507-527, wherein the oxidative catalytically active composite
nanoparticles comprise at least one platinum group metal.
[0840] Embodiment 529. The method of any one of embodiments
507-528, wherein the oxidative catalytically active composite
nanoparticles comprise platinum.
[0841] Embodiment 530. The method of any one of embodiments
507-528, wherein the oxidative catalytically active composite
nanoparticles comprise palladium.
[0842] Embodiment 531. The method of any one of embodiments
507-530, wherein the oxidative catalytically active composite
nanoparticles comprise platinum and palladium.
[0843] Embodiment 532. The method of any one of embodiments
507-531, wherein the first support nanoparticle comprises aluminum
oxide.
[0844] Embodiment 533. The method of any one of embodiments
507-532, wherein the second support nanoparticle comprises cerium
oxide.
[0845] Embodiment 534. The method of any one of embodiments
507-533, wherein the first micron-sized support particle comprises
aluminum oxide.
[0846] Embodiment 535. The method of any one of embodiments
507-534, wherein the second micron-sized support particle comprises
cerium oxide.
[0847] Embodiment 536. The method of any one of embodiments
507-535, wherein the reductive catalytically active composite
nanoparticles comprise reductive catalytically active
Nano-on-Nano-on-micro (NNm) particles.
[0848] Embodiment 537. The method of embodiment 536, wherein the
reductive catalytically active Nano-on-Nano-on-micro (NNm)
particles comprise a platinum group metal.
[0849] Embodiment 538. The method of any one of embodiments
507-535, wherein the reductive catalytically active composite
nanoparticles comprise reductive catalytically active
Nano-on-Nano-in-Micro (NNiM) particles.
[0850] Embodiment 539. The method of embodiment 538, wherein the
reductive catalytically active Nano-on-Nano-in-Micro (NNiM)
particles comprise a platinum group metal.
[0851] Embodiment 540. The method of embodiment 537 or 539, wherein
the platinum group metal is rhodium.
[0852] Embodiment 541. The method of any one of embodiments
507-540, wherein the NO.sub.x trapping particles further comprise
zirconium oxide.
[0853] Embodiment 542. The method of any one of embodiments
507-541, wherein the support nanoparticles have an average diameter
of about 10 nm to about 20 nm.
[0854] Embodiment 543. The method of any one of embodiments
507-541, wherein the support nanoparticles have an average diameter
of about 1 nm to about 5 nm.
[0855] Embodiment 544. The method of embodiment 526, wherein the
washcoat layer comprising oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles further comprises metal oxide
particles and boehmite particles.
[0856] Embodiment 545. The method of embodiment 544, wherein the
metal oxide particles are aluminum oxide particles.
[0857] Embodiment 546. The method of embodiment 545, wherein the
oxidative catalytically active Nano-on-Nano-on-micro (NNm)
particles comprise 35% to 75% by weight of the combination of the
oxidative catalytically active Nano-on-Nano-on-micro (NNm)
particles, boehmite particles, and aluminum oxide particles.
[0858] Embodiment 547. The method of embodiment 545 or 546, wherein
the aluminum oxide particles comprise 30% to 70% by weight of the
combination of the oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles, boehmite particles, and
aluminum oxide particles.
[0859] Embodiment 548. The method of any one of embodiments
545-547, wherein the boehmite particles comprise 2% to 5% by weight
of the combination of the oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles, boehmite particles, and
aluminum oxide particles.
[0860] Embodiment 549. The method of embodiment 545, wherein the
washcoat layer comprising oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles comprises 50% by weight of
the oxidative catalytically active Nano-on-Nano-on-micro (NNm)
particles, 3% by weight of the boehmite particles, and 47% by
weight of the aluminum oxide particles.
[0861] Embodiment 550. The method of embodiment 527, wherein the
washcoat layer comprising oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles further comprises metal
oxide particles and boehmite particles.
[0862] Embodiment 551. The method of embodiment 550, wherein the
metal oxide particles are aluminum oxide particles.
[0863] Embodiment 552. The method of embodiment 551, wherein the
oxidative catalytically active Nano-on-Nano-in-Micro (NNiM)
particles comprise 35% to 75% by weight of the combination of the
oxidative catalytically active Nano-on-Nano-in-Micro (NNiM)
particles, boehmite particles, and aluminum oxide particles.
[0864] Embodiment 553. The method of embodiment 551 or 552, wherein
the aluminum oxide particles comprise 30% to 70% by weight of the
combination of the oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles, boehmite particles, and
aluminum oxide particles.
[0865] Embodiment 554. The method of any one of embodiments
551-553, wherein the boehmite particles comprise 2% to 5% by weight
of the combination of the oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles, boehmite particles, and
aluminum oxide particles.
[0866] Embodiment 555. The method of embodiment 551, wherein the
washcoat layer comprising oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles comprises 50% by weight of
the oxidative catalytically active Nano-on-Nano-in-Micro (NNiM)
particles, 3% by weight of the boehmite particles, and 47% by
weight of the aluminum oxide particles.
[0867] Embodiment 556. The method of embodiment 536, wherein the
washcoat layer comprising reductive catalytically active
Nano-on-Nano-on-micro (NNm) particles and NO.sub.x trapping
particles further comprises boehmite.
[0868] Embodiment 557. The method of embodiment 556, wherein the
reductive catalytically active Nano-on-Nano-on-micro (NNm)
particles comprise 3% to 40% by weight of the combination of the
reductive catalytically active Nano-on-Nano-on-micro (NNm)
particles, NO.sub.x trapping particles, and boehmite particles.
[0869] Embodiment 558. The method of embodiment 556 or 557, wherein
the NO.sub.x trapping particles comprise 30% to 98% by weight of
the combination of the reductive catalytically active
Nano-on-Nano-on-micro (NNm) particles, NO.sub.x trapping particles,
and boehmite particles.
[0870] Embodiment 559. The method of any one of embodiments
556-558, wherein the boehmite particles comprise 1% to 5% by weight
of the combination of the reductive catalytically active
Nano-on-Nano-on-micro (NNm) particles, NO.sub.x trapping particles,
and boehmite particles.
[0871] Embodiment 560. The method of embodiment 556, wherein the
washcoat layer comprising reductive catalytically active
Nano-on-Nano-on-micro (NNm) particles and NO.sub.x trapping
particles comprises 15% by weight of the reductive catalytically
active Nano-on-Nano-on-micro (NNm) particles, 83% by weight of the
NO.sub.x trapping particles, and 2% by weight of the boehmite
particles.
[0872] Embodiment 561. The method of embodiment 538, wherein the
washcoat layer comprising reductive catalytically active
Nano-on-Nano-in-Micro (NNiM) particles and NO.sub.x trapping
particles further comprises boehmite.
[0873] Embodiment 562. The method of embodiment 561, wherein the
reductive catalytically active Nano-on-Nano-in-Micro (NNiM)
particles comprise 3% to 40% by weight of the combination of the
reductive catalytically active Nano-on-Nano-in-Micro (NNiM)
particles, NO.sub.x trapping particles, and boehmite particles.
[0874] Embodiment 563. The method of embodiment 561 or 562, wherein
the cerium oxide particles comprise 30% to 98% by weight of the
combination of the reductive catalytically active
Nano-on-Nano-in-Micro (NNiM) particles, NO.sub.x trapping
particles, and boehmite particles.
[0875] Embodiment 564. The method of any one of embodiments
561-563, wherein the boehmite particles comprise 1% to 5% by weight
of the combination of the reductive catalytically active
Nano-on-Nano-in-Micro (NNiM) particles, NO.sub.x trapping
particles, and boehmite particles.
[0876] Embodiment 565. The method of embodiment 561, wherein the
washcoat layer comprising reductive catalytically active
Nano-on-Nano-in-Micro (NNiM) particles and NO.sub.x trapping
particles comprises 15% by weight of the reductive catalytically
active Nano-on-Nano-in-Micro (NNiM) particles, 83% by weight of the
NO.sub.x trapping particles, and 2% by weight of the boehmite
particles.
[0877] Embodiment 566. The method of any one of embodiments
507-565, wherein the substrate comprises cordierite.
[0878] Embodiment 567. The method of any one of embodiments
507-566, wherein the substrate comprises a honeycomb structure.
[0879] Embodiment 568. The method of embodiment 526, wherein the
washcoat layer comprising oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles has a thickness of 25 g/L to
150 g/L.
[0880] Embodiment 569. The method of embodiment 527, wherein the
washcoat layer comprising oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles has a thickness of 25 g/L to
150 g/L.
[0881] Embodiment 570. The method of embodiment 536, wherein the
washcoat layer comprising reductive catalytically active
Nano-on-Nano-on-micro (NNm) particles and NO.sub.x trapping
particles has a thickness of 100 g/L to 400 g/L.
[0882] Embodiment 571. The method of embodiment 538, wherein the
washcoat layer comprising reductive catalytically active
Nano-on-Nano-in-Micro (NNiM) particles and NO.sub.x trapping
particles has a thickness of 100 g/L to 400 g/L.
[0883] Embodiment 572. The method of any one of embodiments
507-571, wherein the coated substrate has a platinum group metal
loading of 4 g/L or less and a light-off temperature for carbon
monoxide at least 5.degree. C. lower than the light-off temperature
of a substrate with the same platinum group metal loading deposited
by wet-chemistry methods.
[0884] Embodiment 573. The method of any one of embodiments
507-572, said coated substrate having a platinum group metal
loading of about 3.0 g/L to about 5.5 g/L, wherein after 125,000
miles of operation in a vehicular catalytic converter, the coated
substrate has a light-off temperature for carbon monoxide at least
5.degree. C. lower than a coated substrate prepared by depositing
platinum group metals by wet chemical methods having the same
platinum group metal loading after 125,000 miles of operation in a
vehicular catalytic converter.
[0885] Embodiment 574. The method of any one of embodiments
507-573, said coated substrate having a platinum group metal
loading of about 3.0 g/L to about 5.5 g/L, wherein after aging for
16 hours at 800.degree. C., the coated substrate has a light-off
temperature for carbon monoxide at least 5.degree. C. lower than a
coated substrate prepared by depositing platinum group metals by
wet chemical methods having the same platinum group metal loading
after aging for 16 hours at 800.degree. C.
[0886] Embodiment 575. A method of forming a coated substrate, the
method comprising: a) coating the substrate with a washcoat layer
comprising oxidative catalytically active particles comprising
Nano-on-Nano-on-micro (NNm) particles, the oxidative catalytically
active Nano-on-Nano-on-micro (NNm) particles comprising composite
nanoparticles bonded to a first micron-sized carrier particle, and
the composite nanoparticles comprising a first support nanoparticle
and an oxidative catalytic nanoparticle; b) coating a substrate
with a washcoat layer comprising reductive catalytically active
Nano-on-Nano-on-micro (NNm) particles, the reductive catalytically
active Nano-on-Nano-on-micro (NNm) particles comprising composite
nanoparticles bonded to a second micron-sized carrier particle, and
the composite nanoparticles comprising a second support
nanoparticle and a reductive catalytic nanoparticle; and c) coating
the substrate with a washcoat layer comprising NO.sub.x trapping
particles, and the NO.sub.x trapping particles comprising
micron-sized cerium oxide.
[0887] Embodiment 576. The method of embodiment 575, wherein the
NO.sub.x trapping particles further comprise barium oxide
impregnated in the micron-sized cerium oxide.
[0888] Embodiment 577. The method of embodiment 575 or 576 wherein
the NO.sub.x trapping particles further comprise platinum and
palladium impregnated in the micron-sized cerium oxide.
[0889] Embodiment 578. The method of embodiment 576, wherein the
barium oxide is plasma-generated.
[0890] Embodiment 579. The method of embodiment 576, wherein the
barium oxide is impregnated in the micron-sized cerium oxide by wet
chemistry.
[0891] Embodiment 580. The method of embodiment 577, wherein the
platinum and palladium are plasma-generated.
[0892] Embodiment 581. The method of embodiment 577, wherein the
platinum and palladium are impregnated in the micron-sized cerium
oxide by wet chemistry.
[0893] Embodiment 582. The method of embodiment 575, wherein the
NO.sub.x trapping particles further comprise the perovskite
FeBaO.sub.3 impregnated in the micron-sized cerium oxide.
[0894] Embodiment 583. The method of embodiment 575, wherein the
NO.sub.x trapping particles further comprise metal oxides selected
from the group consisting of samarium, zinc, copper, iron, and
silver impregnated in the micron-sized cerium oxide.
[0895] Embodiment 584. The method of embodiment 582 or 583, wherein
the NO.sub.x trapping particles are prepared by wet chemistry.
[0896] Embodiment 585. The method of any one of embodiments
582-584, wherein the NO.sub.x trapping particles further comprise
barium oxide impregnated in the micron-sized cerium oxide.
[0897] Embodiment 586. The method of embodiment 575, wherein the
NO.sub.x trapping particles further comprise micron-sized aluminum
oxide particles.
[0898] Embodiment 587. The method of embodiment 586, wherein the
micron-sized aluminum oxide particles are Nano-on-Nano-on-micro
(NNm) particles.
[0899] Embodiment 588. The method of embodiment 587, wherein the
Nano-on-Nano-on-micro (NNm) particles comprise platinum and/or
palladium.
[0900] Embodiment 589. The method of embodiment 586, wherein the
Nano-on-Nano-on-micro (NNm) particles comprise a non-platinum group
metal.
[0901] Embodiment 590. The method of embodiment 589, wherein the
non-platinum group metal is selected from the group consisting of
tungsten, molybdenum, niobium, manganese, and chromium.
[0902] Embodiment 591. The method of any one of embodiments
586-590, further comprising barium oxide impregnated in the
micron-sized cerium oxide particles.
[0903] Embodiment 592. The method of any one of embodiments
586-591, wherein the Nano-on-Nano-on-micro (NNm) particles further
comprise barium oxide impregnated in the NNm particles.
[0904] Embodiment 593. The method of embodiment 591 or 592, wherein
the barium oxide is impregnated by wet chemistry.
[0905] Embodiment 594. The method of any one of embodiment 575-593,
wherein the composite nanoparticles are plasma-generated.
[0906] Embodiment 595. The method of any one of embodiments
575-594, wherein the oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles comprise at least one
platinum group metal.
[0907] Embodiment 596. The method of any one of embodiments
575-595, wherein the oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles comprise platinum.
[0908] Embodiment 597. The method of any one of embodiments
575-595, wherein the oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles comprise palladium.
[0909] Embodiment 598. The method of any one of embodiments
575-597, wherein the oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles comprise platinum and
palladium.
[0910] Embodiment 599. The method of any one of embodiments
575-598, wherein the first support nanoparticle comprises aluminum
oxide.
[0911] Embodiment 600. The method of any one of embodiments
575-599, wherein the second support nanoparticle comprises cerium
oxide.
[0912] Embodiment 601. The method of any one of embodiments
575-600, wherein the first micron-sized carrier particle comprises
aluminum oxide.
[0913] Embodiment 602. The method of any one of embodiments
575-601, wherein the second micron-sized carrier particle comprises
cerium oxide.
[0914] Embodiment 603. The method of any one of embodiments
575-602, wherein the reductive catalytically active
Nano-on-Nano-on-micro (NNm) particles comprise a platinum group
metal.
[0915] Embodiment 604. The method of embodiment 603, wherein the
platinum group metal is rhodium.
[0916] Embodiment 605. The method of any one of embodiments
575-604, wherein the NO.sub.x trapping particles further comprise
zirconium oxide.
[0917] Embodiment 606. The method of any one of embodiments
575-605, wherein the support nanoparticles have an average diameter
of about 10 nm to about 20 nm.
[0918] Embodiment 607. The method of any one of embodiments
575-605, wherein the support nanoparticles have an average diameter
of about 1 nm to about 5 nm.
[0919] Embodiment 608. The method of any one of embodiments
575-607, wherein the washcoat layer comprising oxidative
catalytically active Nano-on-Nano-on-micro (NNm) particles further
comprises metal oxide particles and boehmite particles.
[0920] Embodiment 609. The method of embodiment 608, wherein the
metal oxide particles are aluminum oxide particles.
[0921] Embodiment 610. The method of embodiment 609, wherein the
oxidative catalytically active Nano-on-Nano-on-micro (NNm)
particles comprise 35% to 75% by weight of the combination of the
oxidative catalytically active Nano-on-Nano-on-micro (NNm)
particles, boehmite particles, and aluminum oxide particles.
[0922] Embodiment 611. The method of embodiment 609 or 610, wherein
the aluminum oxide particles comprise 30% to 70% by weight of the
combination of the oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles, boehmite particles, and
aluminum oxide particles.
[0923] Embodiment 612. The method of any one of embodiments
609-611, wherein the beohmite particles comprise 2% to 5% by weight
of the combination of the oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles, boehmite particles, and
aluminum oxide particles.
[0924] Embodiment 613. The method of embodiment 609, wherein the
washcoat layer comprising oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles comprises 50% by weight of
the oxidative catalytically active Nano-on-Nano-on-micro (NNm)
particles, 3% by weight of the boehmite particles, and 47% by
weight of the aluminum oxide particles.
[0925] Embodiment 614. The method of any one of embodiments
575-613, wherein the washcoat layer comprising reductive
catalytically active Nano-on-Nano-on-micro (NNm) particles further
comprises metal oxide particles and boehmite particles.
[0926] Embodiment 615. The method of embodiment 614, wherein the
metal oxide particles are aluminum oxide particles.
[0927] Embodiment 616. The method of embodiment 615, wherein the
reductive catalytically active Nano-on-Nano-on-micro (NNm)
particles comprise 50% to 95% by weight of the combination of the
reductive catalytically active Nano-on-Nano-on-micro (NNm)
particles, aluminum oxide particles, and boehmite particles.
[0928] Embodiment 617. The method of embodiment 615 or 616, wherein
the aluminum oxide particles comprise 5% to 40% by weight of the
combination of the reductive catalytically active
Nano-on-Nano-on-micro (NNm) particles, aluminum oxide particles,
and boehmite particles.
[0929] Embodiment 618. The method of any one of embodiments
615-617, wherein the boehmite particles comprise 2% to 5% by weight
of the combination of the reductive catalytically active
Nano-on-Nano-on-micro (NNm) particles, aluminum oxide particles,
and boehmite particles.
[0930] Embodiment 619. The method of embodiment 615, wherein the
washcoat layer comprising reductive catalytically active
Nano-on-Nano-on-micro (NNm) particles comprises 80% by weight of
the reductive catalytically active Nano-on-Nano-on-micro (NNm)
particles, 17% by weight of the aluminum oxide particles, and 3% by
weight of the boehmite particles.
[0931] Embodiment 620. The method of any one of embodiments
575-619, wherein the washcoat layer comprising NO.sub.x trapping
particles further comprises Nano-on-Nano-on-micro (NNm) particles
and boehmite particles.
[0932] Embodiment 621. The method of embodiment 620, wherein the
Nano-on-Nano-on-micro (NNm) particles comprise a platinum group
metal.
[0933] Embodiment 622. The method of embodiment 621, wherein the
platinum group metal is selected from the group consisting of
ruthenium, platinum, and palladium.
[0934] Embodiment 623. The method of embodiment 620, wherein the
NO.sub.x trapping Nano-on-Nano-on-micro (NNm) particles comprise a
non-platinum group metal.
[0935] Embodiment 624. The method of embodiment 623, wherein the
non-platinum group metal is selected from the group consisting of
tungsten, molybdenum, niobium, manganese, and chromium.
[0936] Embodiment 625. The method of any one of embodiments
620-624, wherein the Nano-on-Nano-on-micro (NNm) particles comprise
10% to 40% by weight of the combination of the
Nano-on-Nano-on-micro (NNm) particles, NO.sub.x trapping particles,
and boehmite particles.
[0937] Embodiment 626. The method of any one of embodiments
620-625, wherein the micron-sized cerium oxide particles comprise
50% to 90% by weight of the combination of the
Nano-on-Nano-on-micro (NNm) particles, NO.sub.x trapping particles,
and boehmite particles.
[0938] Embodiment 627. The method of any one of embodiments
620-626, wherein the boehmite particles comprise 2% to 5% by weight
of the combination of the Nano-on-Nano-on-micro (NNm) particles,
NO.sub.x trapping particles, and boehmite particles.
[0939] Embodiment 628. The method of any one of embodiments
620-627, wherein the washcoat layer comprising micron-sized cerium
oxide particles comprises 73% by weight of the NO.sub.x trapping
particles, 23% by weight of the Nano-on-Nano-on-micro (NNm)
particles, and 4% by weight of the boehmite particles.
[0940] Embodiment 629. The method of any one of embodiments
575-628, wherein the substrate comprises cordierite.
[0941] Embodiment 630. The method of any one of embodiments
575-629, wherein the substrate comprises a honeycomb structure.
[0942] Embodiment 631. The method of any one of embodiments
575-630, wherein the washcoat layer comprising oxidative
catalytically active Nano-on-Nano-on-micro (NNm) particles has a
thickness of 25 g/L to 150 g/L.
[0943] Embodiment 632. The method of any one of embodiments
575-631, wherein the washcoat layer comprising reductive
catalytically active Nano-on-Nano-on-micro (NNm) particles has a
thickness of 25 g/L to 150 g/L.
[0944] Embodiment 633. The method of any one of embodiments
575-632, wherein the washcoat layer comprising NO.sub.x trapping
particles has a thickness of 100 g/L to 400 g/L.
[0945] Embodiment 634. The method of any one of embodiments
575-633, wherein the coated substrate has a platinum group metal
loading of 4 g/L or less and a light-off temperature for carbon
monoxide at least 5.degree. C. lower than the light-off temperature
of a substrate with the same platinum group metal loading deposited
by wet-chemistry methods.
[0946] Embodiment 635. The method of any one of embodiments
575-634, said coated substrate having a platinum group metal
loading of about 3.0 g/L to about 5.5 g/L, wherein after 125,000
miles of operation in a vehicular catalytic converter, the coated
substrate has a light-off temperature for carbon monoxide at least
5.degree. C. lower than a coated substrate prepared by depositing
platinum group metals by wet chemical methods having the same
platinum group metal loading after 125,000 miles of operation in a
vehicular catalytic converter.
[0947] Embodiment 636. The method of any one of embodiments 575-635
said coated substrate having a platinum group metal loading of
about 3.0 g/L to about 5.5 g/L, wherein after aging for 16 hours at
800.degree. C., the coated substrate has a light-off temperature
for carbon monoxide at least 5.degree. C. lower than a coated
substrate prepared by depositing platinum group metals by wet
chemical methods having the same platinum group metal loading after
aging for 16 hours at 800.degree. C.
[0948] Embodiment 637. A method of forming a coated substrate, the
method comprising: a) coating a substrate with a washcoat
composition comprising oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles, the oxidative catalytically
active Nano-on-Nano-in-Micro (NNiM) particles comprising composite
nanoparticles embedded in a first micron-sized porous carrier, and
the composite nanoparticles comprising a first support nanoparticle
and an oxidative catalytic nanoparticle; b) coating a substrate
with a washcoat composition comprising reductive catalytically
active Nano-on-Nano-in-Micro (NNiM) particles, the reductive
catalytically active Nano-on-Nano-in-Micro (NNiM) particles
comprising composite nanoparticles embedded in a second
micron-sized porous carrier, and the composite nanoparticles
comprising a second support nanoparticle and an oxidative catalytic
nanoparticle; and c) coating the substrate with a washcoat
composition comprising NO.sub.x trapping particles, and the
NO.sub.x trapping particles comprising micron-sized cerium
oxide.
[0949] Embodiment 638. The method of embodiment 637, wherein the
NO.sub.x trapping particles further comprise barium oxide
impregnated in the micron-sized cerium oxide.
[0950] Embodiment 639. The method of embodiment 637 or 638, wherein
the NO.sub.x trapping particles further comprise platinum and
palladium impregnated in the micron-sized cerium oxide.
[0951] Embodiment 640. The method of embodiment 638, wherein the
barium oxide is plasma-generated.
[0952] Embodiment 641. The method of embodiment 638, wherein the
barium oxide is impregnated in the micron-sized cerium oxide by wet
chemistry.
[0953] Embodiment 642. The method of embodiment 639, wherein the
platinum and palladium are plasma-generated.
[0954] Embodiment 643. The method of embodiment 639, wherein the
platinum and palladium are impregnated in the micron-sized cerium
oxide by wet chemistry.
[0955] Embodiment 644. The method of embodiment 637, wherein the
NO.sub.x trapping particles further comprise the perovskite
FeBaO.sub.3 impregnated in the micron-sized cerium oxide.
[0956] Embodiment 645. The method of embodiment 637, wherein the
NO.sub.x trapping particles further comprise metal oxides selected
from the group consisting of samarium, zinc, copper, iron, and
silver impregnated in the micron-sized cerium oxide.
[0957] Embodiment 646. The method of embodiment 644 or 645, wherein
the NO.sub.x trapping particles are prepared by wet chemistry.
[0958] Embodiment 647. The method of any one of embodiments
644-646, wherein the NO.sub.x trapping particles further comprise
barium oxide impregnated in the micron-sized cerium oxide.
[0959] Embodiment 648. The method of embodiment 637, wherein the
NO.sub.x trapping particles further comprise micron-sized aluminum
oxide particles.
[0960] Embodiment 649. The method of embodiment 648, wherein the
micron-sized aluminum oxide particles are Nano-on-Nano-in-Micro
(NNiM) particles.
[0961] Embodiment 650. The method of embodiment 649, wherein the
Nano-on-Nano-in-Micro (NNiM) particles comprise platinum and/or
palladium.
[0962] Embodiment 651. The method of embodiment 648, wherein the
Nano-on-Nano-in-Micro (NNiM) particles comprise a non-platinum
group metal.
[0963] Embodiment 652. The method of embodiment 651, wherein the
non-platinum group metal is selected from the group consisting of
tungsten, molybdenum, niobium, manganese, and chromium.
[0964] Embodiment 653. The method of any one of embodiments
648-652, further comprising barium oxide impregnated in the
micron-sized cerium oxide particles.
[0965] Embodiment 654. The method of any one of embodiments
648-653, wherein the Nano-on-Nano-in-Micro (NNiM) particles further
comprise barium oxide impregnated in the NNiM particles.
[0966] Embodiment 655. The method of embodiment 653 or 654, wherein
the barium oxide is impregnated by wet chemistry.
[0967] Embodiment 656. The method of any one of embodiment 637-655,
wherein the composite nanoparticles are plasma-generated.
[0968] Embodiment 657. The method of any one of embodiments
637-656, wherein the oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles comprise at least one
platinum group metal.
[0969] Embodiment 658. The method of any one of embodiments
637-657, wherein the oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles comprise platinum.
[0970] Embodiment 659. The method of any one of embodiments
637-657, wherein the oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles comprise palladium.
[0971] Embodiment 660. The method of any one of embodiments
637-659, wherein the oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles comprise platinum and
palladium.
[0972] Embodiment 661. The method of any one of embodiments
637-660, wherein the first support nanoparticle comprises aluminum
oxide.
[0973] Embodiment 662. The method of any one of embodiments
637-661, wherein the second support nanoparticle comprises cerium
oxide.
[0974] Embodiment 663. The method of any one of embodiments
637-662, wherein the first micron-sized porous carrier comprises
aluminum oxide.
[0975] Embodiment 664. The method of any one of embodiments
637-663, wherein the second micron-sized porous carrier comprises
cerium oxide.
[0976] Embodiment 665. The method of any one of embodiments
637-664, wherein the reductive catalytically active
Nano-on-Nano-in-Micro (NNiM) particles comprise a platinum group
metal.
[0977] Embodiment 666. The method of embodiment 665, wherein the
platinum group metal is rhodium.
[0978] Embodiment 667. The method of any one of embodiments
637-666, wherein the NO.sub.x trapping particles further comprise
zirconium oxide.
[0979] Embodiment 668. The method of any one of embodiments
637-667, wherein the support nanoparticles have an average diameter
of about 10 nm to about 20 nm.
[0980] Embodiment 669. The method of any one of embodiments
637-667, wherein the support nanoparticles have an average diameter
of about 1 nm to about 5 nm.
[0981] Embodiment 670. The method of any one of embodiments
637-669, wherein the washcoat layer comprising oxidative
catalytically active Nano-on-Nano-in-Micro (NNiM) particles further
comprises metal oxide particles and boehmite particles.
[0982] Embodiment 671. The method of embodiment 670, wherein the
metal oxide particles are aluminum oxide particles.
[0983] Embodiment 672. The method of embodiment 671, wherein the
oxidative catalytically active Nano-on-Nano-in-Micro (NNiM)
particles comprise 35% to 75% by weight of the combination of the
oxidative catalytically active Nano-on-Nano-in-Micro (NNiM)
particles, boehmite particles, and aluminum oxide particles.
[0984] Embodiment 673. The method of embodiment 671 or 672, wherein
the aluminum oxide particles comprise 30% to 70% by weight of the
combination of the oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles, boehmite particles, and
aluminum oxide particles.
[0985] Embodiment 674. The method of any one of embodiments
671-673, wherein the boehmite particles comprise 2% to 5% by weight
of the combination of the oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles, boehmite particles, and
aluminum oxide particles.
[0986] Embodiment 675. The method of embodiment 671, wherein the
washcoat layer comprising oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles comprises 50% by weight of
the oxidative catalytically active Nano-on-Nano-in-Micro (NNiM)
particles, 3% by weight of the boehmite particles, and 47% by
weight of the aluminum oxide particles.
[0987] Embodiment 676. The method of any one of embodiments
637-675, wherein the washcoat layer comprising reductive
catalytically active Nano-on-Nano-in-Micro (NNiM) particles further
comprises metal oxide particles and boehmite particles.
[0988] Embodiment 677. The method of embodiment 676, wherein the
metal oxide particles are aluminum oxide particles.
[0989] Embodiment 678. The method of embodiment 677, wherein the
reductive catalytically active Nano-on-Nano-in-Micro (NNiM)
particles comprise 50% to 95% by weight of the combination of the
reductive catalytically active Nano-on-Nano-in-Micro (NNiM)
particles, aluminum oxide particles, and boehmite particles.
[0990] Embodiment 679. The method of embodiment 677 or 678, wherein
the aluminum oxide particles comprise 5% to 40% by weight of the
combination of the reductive catalytically active
Nano-on-Nano-in-Micro (NNiM) particles, aluminum oxide particles,
and boehmite particles.
[0991] Embodiment 680. The method of any one of embodiments
677-679, wherein the boehmite particles comprise 2% to 5% by weight
of the combination of the reductive catalytically active
Nano-on-Nano-in-Micro (NNiM) particles, aluminum oxide particles,
and boehmite particles.
[0992] Embodiment 681. The method of embodiment 677, wherein the
washcoat layer comprising reductive catalytically active
Nano-on-Nano-in-Micro (NNiM) particles comprises 80% by weight of
the reductive catalytically active Nano-on-Nano-in-Micro (NNiM)
particles, 17% by weight of the aluminum oxide particles, and 3% by
weight of the boehmite particles.
[0993] Embodiment 682. The method of any one of embodiments
637-681, wherein the washcoat layer comprising NO.sub.x trapping
particles further comprises Nano-on-Nano-in-Micro (NNiM) particles
and boehmite particles.
[0994] Embodiment 683. The method of embodiment 682, wherein the
Nano-on-Nano-in-Micro (NNiM) particles comprise at least one
platinum group metal.
[0995] Embodiment 684. The method of embodiment 683, wherein the
platinum group metal is selected from the group consisting of
ruthenium, platinum, and palladium.
[0996] Embodiment 685. The method of embodiment 682, wherein the
Nano-on-Nano-in-Micro (NNiM) particles comprise a non-platinum
group metal.
[0997] Embodiment 686. The method of embodiment 685, wherein the
non-platinum group metal is selected from the group consisting of
tungsten, molybdenum, niobium, manganese, and chromium.
[0998] Embodiment 687. The method of any one of embodiments
682-686, wherein the Nano-on-Nano-in-Micro (NNiM) particles
comprise 10% to 40% by weight of the combination of the
Nano-on-Nano-in-Micro (NNiM) particles, NO.sub.x trapping
particles, and boehmite particles.
[0999] Embodiment 688. The method of any one of embodiments
682-687, wherein the NO.sub.x trapping particles comprise 50% to
90% by weight of the combination of the Nano-on-Nano-in-Micro
(NNiM) particles, NO.sub.x trapping particles, and boehmite
particles.
[1000] Embodiment 689. The method of any one of embodiments
682-688, wherein the boehmite particles comprise 2% to 5% by weight
of the combination of the Nano-on-Nano-in-Micro (NNiM) particles,
NO.sub.x trapping particles, and boehmite particles.
[1001] Embodiment 690. The method of any one of embodiments
682-689, wherein the washcoat layer comprising NO.sub.x trapping
particles comprises 73% by weight of the NO.sub.x trapping
particles, 23% by weight of the Nano-on-Nano-in-Micro (NNiM)
particles, and 4% by weight of the boehmite particles.
[1002] Embodiment 691. The method of any one of embodiments
637-690, wherein the substrate comprises cordierite.
[1003] Embodiment 692. The method of any one of embodiments
637-691, wherein the substrate comprises a honeycomb structure.
[1004] Embodiment 693. The method of any one of embodiments
637-692, wherein the washcoat layer comprising oxidative
catalytically active Nano-on-Nano-in-Micro (NNiM) particles has a
thickness of 25 g/L to 150 g/L.
[1005] Embodiment 694. The method of any one of embodiments
637-693, wherein the washcoat layer comprising reductive
catalytically active Nano-on-Nano-in-Micro (NNiM) particles has a
thickness of 25 g/L to 150 g/L.
[1006] Embodiment 695. The method of any one of embodiments
637-694, wherein the washcoat layer comprising NO.sub.x trapping
particles has a thickness of 100 g/L to 400 g/L.
[1007] Embodiment 696. The method of any one of embodiments
637-695, wherein the coated substrate has a platinum group metal
loading of 4 g/L or less and a light-off temperature for carbon
monoxide at least 5.degree. C. lower than the light-off temperature
of a substrate with the same platinum group metal loading deposited
by wet-chemistry methods.
[1008] Embodiment 697. The method of any one of embodiments
637-696, said coated substrate having a platinum group metal
loading of about 3.0 g/L to about 5.5 g/L, wherein after 125,000
miles of operation in a vehicular catalytic converter, the coated
substrate has a light-off temperature for carbon monoxide at least
5.degree. C. lower than a coated substrate prepared by depositing
platinum group metals by wet chemical methods having the same
platinum group metal loading after 125,000 miles of operation in a
vehicular catalytic converter.
[1009] Embodiment 698. The method of any one of embodiments
637-697, said coated substrate having a platinum group metal
loading of about 3.0 g/L to about 5.5 g/L, wherein after aging for
16 hours at 800.degree. C., the coated substrate has a light-off
temperature for carbon monoxide at least 5.degree. C. lower than a
coated substrate prepared by depositing platinum group metals by
wet chemical methods having the same platinum group metal loading
after aging for 16 hours at 800.degree. C.
[1010] Embodiment 699. A method of forming a coated substrate, the
method comprising: a) coating a substrate with a washcoat
composition comprising oxidative catalytically active composite
nanoparticles attached to a first micron-sized support particle,
the oxidative catalytically active composite nanoparticles being
plasma-generated and comprising a first support nanoparticle and an
oxidative catalytic nanoparticle; b) coating a substrate with a
washcoat composition comprising reductive catalytically active
composite nanoparticles attached to a second micron-sized support
particle, the reductive catalytically active composite
nanoparticles being plasma-generated and comprising a second
support nanoparticle and a reductive catalytic nanoparticle; and c)
coating the substrate with a washcoat composition comprising
NO.sub.x trapping particles, and the NO.sub.x trapping particles
comprising micron-sized cerium oxide.
[1011] Embodiment 700. The method of embodiment 699, wherein the
NO.sub.x trapping particles further comprise barium oxide
impregnated in the micron-sized cerium oxide.
[1012] Embodiment 701. The method of embodiment 699 or 700, wherein
the NO.sub.x trapping particles further comprise platinum and
palladium impregnated in the micron-sized cerium oxide.
[1013] Embodiment 702. The method of embodiment 700, wherein the
barium oxide is plasma-generated.
[1014] Embodiment 703. The method of embodiment 700, wherein the
barium oxide is impregnated in the micron-sized cerium oxide by wet
chemistry.
[1015] Embodiment 704. The method of embodiment 701, wherein the
platinum and palladium are plasma-generated.
[1016] Embodiment 705. The method of embodiment 701, wherein the
platinum and palladium are impregnated in the micron-sized cerium
oxide by wet chemistry.
[1017] Embodiment 706. The method of embodiment 699, wherein the
NO.sub.x trapping particles further comprise the perovskite
FeBaO.sub.3 impregnated in the micron-sized cerium oxide.
[1018] Embodiment 707. The method of embodiment 699, wherein the
NO.sub.x trapping particles further comprise metal oxides selected
from the group consisting of samarium, zinc, copper, iron, and
silver impregnated in the micron-sized cerium oxide.
[1019] Embodiment 708. The method of embodiment 706 or 707, wherein
the NO.sub.x trapping particles are prepared by wet chemistry.
[1020] Embodiment 709. The method of any one of embodiments
706-708, wherein the NO.sub.x trapping particles further comprise
barium oxide impregnated in the micron-sized cerium oxide.
[1021] Embodiment 710. The method of embodiment 699, wherein the
NO.sub.x trapping particles further comprise micron-sized aluminum
oxide particles.
[1022] Embodiment 711. The method of embodiment 710, wherein the
micron-sized aluminum oxide particles are Nano-on-Nano-on-micro
(NNm) particles or Nano-on-Nano-in-Micro (NNiM) particles.
[1023] Embodiment 712. The method of embodiment 711, wherein the
Nano-on-Nano-on-micro (NNm) particles or Nano-on-Nano-in-Micro
(NNiM) particles comprise platinum and/or palladium.
[1024] Embodiment 713. The method of embodiment 710, wherein the
Nano-on-Nano-on-micro (NNm) particles or Nano-on-Nano-in-Micro
(NNiM) particles comprise a non-platinum group metal.
[1025] Embodiment 714. The method of embodiment 713, wherein the
non-platinum group metal is selected from the group consisting of
tungsten, molybdenum, niobium, manganese, and chromium.
[1026] Embodiment 715. The method of any one of embodiments
699-714, further comprising barium oxide impregnated in the
micron-sized cerium oxide particles.
[1027] Embodiment 716. The method of any one of embodiments
699-714, wherein the Nano-on-Nano-on-micro (NNm) particles or or
Nano-on-Nano-in-Micro (NNiM) particles further comprise barium
oxide impregnated in the NNm or NNiM particles.
[1028] Embodiment 717. The method of embodiment 715 or 716, wherein
the barium oxide is impregnated by wet chemistry.
[1029] Embodiment 718. The method of any one of embodiment 699-717,
wherein the oxidative catalytically active composite nanoparticles
attached to a first micron-sized support particle comprise
oxidative catalytically active Nano-on-Nano-on-micro (NNm)
particles.
[1030] Embodiment 719. The method of any one of embodiments
699-717, wherein the oxidative catalytically active composite
nanoparticles attached to a first micron-sized support particle
comprise oxidative catalytically active Nano-on-Nano-in-Micro
(NNiM) particles.
[1031] Embodiment 720. The method of any one of embodiments
699-719, wherein the oxidative catalytically active composite
nanoparticles comprise at least one platinum group metal.
[1032] Embodiment 721. The method of any one of embodiment 699-720,
wherein the oxidative catalytically active composite nanoparticles
comprise platinum.
[1033] Embodiment 722. The method of any one of embodiment 699-720,
wherein the oxidative catalytically active composite nanoparticles
comprise palladium.
[1034] Embodiment 723. The method of any one of embodiments
699-722, wherein the oxidative catalytically active composite
nanoparticles comprise platinum and palladium.
[1035] Embodiment 724. The method of any one of embodiments
699-723, wherein the first support nanoparticle comprises aluminum
oxide.
[1036] Embodiment 725. The method of any one of embodiments
699-724, wherein the second support nanoparticle comprises cerium
oxide.
[1037] Embodiment 726. The method of any one of embodiments
699-725, wherein the first micron-sized support particle comprises
aluminum oxide.
[1038] Embodiment 727. The method of any one of embodiments
699-726, wherein the second micron-sized support particle comprises
cerium oxide.
[1039] Embodiment 728. The method of any one of embodiments
699-727, wherein the reductive catalytically active composite
nanoparticles comprise reductive catalytically active
Nano-on-Nano-on-micro (NNm) particles.
[1040] Embodiment 729. The method of embodiment 728, wherein the
reductive catalytically active Nano-on-Nano-on-micro (NNm)
particles comprise a platinum group metal.
[1041] Embodiment 730. The method of any one of embodiments
699-727, wherein the reductive catalytically active composite
nanoparticles comprise reductive catalytically active
Nano-on-Nano-in-Micro (NNiM) particles.
[1042] Embodiment 731. The method of embodiment 730, wherein the
reductive catalytically active Nano-on-Nano-in-Micro (NNiM)
particles comprise a platinum group metal.
[1043] Embodiment 732. The method of embodiment 729 or 731, wherein
the platinum group metal is rhodium.
[1044] Embodiment 733. The method of any one of embodiments
699-732, wherein the NO.sub.x trapping particles further comprise
zirconium oxide.
[1045] Embodiment 734. The method of any one of embodiments
699-733, wherein the support nanoparticles have an average diameter
of about 10 nm to about 20 nm.
[1046] Embodiment 735. The method of any one of embodiments
699-733, wherein the support nanoparticles have an average diameter
of about 1 nm to about 5 nm.
[1047] Embodiment 736. The method of embodiment 718, wherein the
washcoat layer comprising oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles further comprises metal oxide
particles and boehmite particles.
[1048] Embodiment 737. The method of embodiment 736, wherein the
metal oxide particles are aluminum oxide particles.
[1049] Embodiment 738. The method of embodiment 737, wherein the
oxidative catalytically active Nano-on-Nano-on-micro (NNm)
particles comprise 35% to 75% by weight of the combination of the
oxidative catalytically active Nano-on-Nano-on-micro (NNm)
particles, boehmite particles, and aluminum oxide particles.
[1050] Embodiment 739. The method of embodiment 737 or 738, wherein
the aluminum oxide particles comprise 30% to 70% by weight of the
combination of the oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles, boehmite particles, and
aluminum oxide particles.
[1051] Embodiment 740. The method of any one of embodiments
737-739, wherein the boehmite particles comprise 2% to 5% by weight
of the combination of the oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles, boehmite particles, and
aluminum oxide particles.
[1052] Embodiment 741. The method of embodiment 737, wherein the
washcoat layer comprising oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles comprises 50% by weight of
the oxidative catalytically active Nano-on-Nano-on-micro (NNm)
particles, 3% by weight of the boehmite particles, and 47% by
weight of the aluminum oxide particles.
[1053] Embodiment 742. The method of embodiment 719, wherein the
washcoat layer comprising oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles further comprises metal
oxide particles and boehmite particles.
[1054] Embodiment 743. The method of embodiment 742, wherein the
metal oxide particles are aluminum oxide particles.
[1055] Embodiment 744. The method of embodiment 743, wherein the
oxidative catalytically active Nano-on-Nano-in-Micro (NNiM)
particles comprise 35% to 75% by weight of the combination of the
oxidative catalytically active Nano-on-Nano-in-Micro (NNiM)
particles, boehmite particles, and aluminum oxide particles.
[1056] Embodiment 745. The method of embodiment 743 or 744, wherein
the aluminum oxide particles comprise 30% to 70% by weight of the
combination of the oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles, boehmite particles, and
aluminum oxide particles.
[1057] Embodiment 746. The method of any one of embodiments
743-745, wherein the boehmite particles comprise 2% to 5% by weight
of the combination of the oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles, boehmite particles, and
aluminum oxide particles.
[1058] Embodiment 747. The method of embodiment 743, wherein the
washcoat layer comprising oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles comprises 50% by weight of
the oxidative catalytically active Nano-on-Nano-in-Micro (NNiM)
particles, 3% by weight of the boehmite particles, and 47% by
weight of the aluminum oxide particles.
[1059] Embodiment 748. The method of embodiment 728, wherein the
washcoat layer comprising reductive catalytically active
Nano-on-Nano-on-micro (NNm) particles further comprises metal oxide
particles and boehmite particles.
[1060] Embodiment 749. The method of embodiment 748, wherein the
metal oxide particles are aluminum oxide particles.
[1061] Embodiment 750. The method of embodiment 749, wherein the
reductive catalytically active Nano-on-Nano-on-micro (NNm)
particles comprise 50% to 95% by weight of the combination of the
reductive catalytically active Nano-on-Nano-on-micro (NNm)
particles, aluminum oxide particles, and boehmite particles.
[1062] Embodiment 751. The method of embodiment 749 or 750, wherein
the aluminum oxide particles comprise 5% to 40% by weight of the
combination of the reductive catalytically active
Nano-on-Nano-on-micro (NNm) particles, aluminum oxide particles,
and boehmite particles.
[1063] Embodiment 752. The method of any one of embodiments
749-751, wherein the boehmite particles comprise 2% to 5% by weight
of the combination of the reductive catalytically active
Nano-on-Nano-on-micro (NNm) particles, aluminum oxide particles,
and boehmite particles.
[1064] Embodiment 753. The method of embodiment 749, wherein the
washcoat layer comprising reductive catalytically active
Nano-on-Nano-on-micro (NNm) particles comprises 80% by weight of
the reductive catalytically active Nano-on-Nano-on-micro (NNm)
particles, 17% by weight of the aluminum oxide particles, and 3% by
weight of the boehmite particles.
[1065] Embodiment 754. The method of embodiment 730, wherein the
washcoat layer comprising reductive catalytically active
Nano-on-Nano-in-Micro (NNiM) particles further comprises metal
oxide particles and boehmite particles.
[1066] Embodiment 755. The method of embodiment 754, wherein the
metal oxide particles are aluminum oxide particles.
[1067] Embodiment 756. The method of embodiment 755, wherein the
reductive catalytically active Nano-on-Nano-in-Micro (NNiM)
particles comprise 50% to 95% by weight of the combination of the
reductive catalytically active Nano-on-Nano-in-Micro (NNiM)
particles, aluminum oxide particles, and boehmite particles.
[1068] Embodiment 757. The method of embodiment 755 or 756, wherein
the aluminum oxide particles comprise 5% to 40% by weight of the
combination of the reductive catalytically active
Nano-on-Nano-in-Micro (NNiM) particles, aluminum oxide particles,
and boehmite particles.
[1069] Embodiment 758. The method of any one of embodiments
755-757, wherein the boehmite particles comprise 2% to 5% by weight
of the combination of the reductive catalytically active
Nano-on-Nano-in-Micro (NNiM) particles, aluminum oxide particles,
and boehmite particles.
[1070] Embodiment 759. The method of embodiment 755, wherein the
washcoat layer comprising reductive catalytically active
Nano-on-Nano-in-Micro (NNiM) particles comprises 80% by weight of
the reductive catalytically active Nano-on-Nano-in-Micro (NNiM)
particles, 17% by weight of the aluminum oxide particles, and 3% by
weight of the boehmite particles.
[1071] Embodiment 760. The method of any one of embodiments
699-759, wherein the washcoat layer comprising NO.sub.x trapping
particles further comprises Nano-on-Nano-on-micro (NNm) particles
and boehmite particles.
[1072] Embodiment 761. The method of embodiment 760, wherein the
Nano-on-Nano-on-micro (NNm) particles comprise at least one
platinum group metal.
[1073] Embodiment 762. The method of embodiment 761, wherein the
platinum group metal is selected from the group consisting of
ruthenium, platinum, and palladium.
[1074] Embodiment 763. The method of embodiment 760, wherein the
Nano-on-Nano-on-micro (NNm) particles comprise a non-platinum group
metal.
[1075] Embodiment 764. The method of embodiment 763, wherein the
non-platinum group metal is selected from the group consisting of
tungsten, molybdenum, niobium, manganese, and chromium.
[1076] Embodiment 765. The method of any one of embodiments
760-764, wherein the Nano-on-Nano-on-micro (NNm) particles comprise
10% to 40% by weight of the combination of the
Nano-on-Nano-on-micro (NNm) particles, NO.sub.x trapping particles,
and boehmite particles.
[1077] Embodiment 766. The method of any one of embodiments
760-765, wherein the NO.sub.x trapping particles comprise 50% to
90% by weight of the combination of the Nano-on-Nano-on-micro (NNm)
particles, NO.sub.x trapping particles, and boehmite particles.
[1078] Embodiment 767. The method of any one of embodiments
760-766, wherein the boehmite particles comprise 2% to 5% by weight
of the combination of the Nano-on-Nano-on-micro (NNm) particles,
NO.sub.x trapping particles, and boehmite particles.
[1079] Embodiment 768. The method of any one of embodiments
760-767, wherein the washcoat layer comprising NO.sub.x trapping
particles comprises 73% by weight of the NO.sub.x trapping
particles, 23% by weight of the Nano-on-Nano-on-micro (NNm)
particles, and 4% by weight of the boehmite particles.
[1080] Embodiment 769. The method of any one of embodiments
699-768, wherein the substrate comprises cordierite.
[1081] Embodiment 770. The method of any one of embodiments
699-769, wherein the substrate comprises a honeycomb structure.
[1082] Embodiment 771. The method of embodiment 718, wherein the
washcoat layer comprising oxidative catalytically active
Nano-on-Nano-on-micro (NNm) particles has a thickness of 25 g/L to
150 g/L.
[1083] Embodiment 772. The method of embodiment 719, wherein the
washcoat layer comprising oxidative catalytically active
Nano-on-Nano-in-Micro (NNiM) particles has a thickness of 25 g/L to
150 g/L.
[1084] Embodiment 773. The method of embodiment 728, wherein the
washcoat layer comprising reductive catalytically active
Nano-on-Nano-on-micro (NNm) particles has a thickness of 100 g/L to
400 g/L.
[1085] Embodiment 774. The method of embodiment 730, wherein the
washcoat layer comprising reductive catalytically active
Nano-on-Nano-in-Micro (NNiM) particles has a thickness of 100 g/L
to 400 g/L.
[1086] Embodiment 775. The method of any one of embodiments
699-774, wherein the washcoat layer comprising NO.sub.x trapping
particles particles has a thickness of 100 g/L to 400 g/L.
[1087] Embodiment 776. The method of any one of embodiments
699-775, wherein the coated substrate has a platinum group metal
loading of 4 g/L or less and a light-off temperature for carbon
monoxide at least 5.degree. C. lower than the light-off temperature
of a substrate with the same platinum group metal loading deposited
by wet-chemistry methods.
[1088] Embodiment 777. The method of any one of embodiments
699-776, said coated substrate having a platinum group metal
loading of about 3.0 g/L to about 5.5 g/L, wherein after 125,000
miles of operation in a vehicular catalytic converter, the coated
substrate has a light-off temperature for carbon monoxide at least
5.degree. C. lower than a coated substrate prepared by depositing
platinum group metals by wet chemical methods having the same
platinum group metal loading after 125,000 miles of operation in a
vehicular catalytic converter.
[1089] Embodiment 778. The method of any one of embodiments
699-777, said coated substrate having a platinum group metal
loading of about 3.0 g/L to about 5.5 g/L, wherein after aging for
16 hours at 800.degree. C., the coated substrate has a light-off
temperature for carbon monoxide at least 5.degree. C. lower than a
coated substrate prepared by depositing platinum group metals by
wet chemical methods having the same platinum group metal loading
after aging for 16 hours at 800.degree. C.
EXAMPLES
[1090] As discussed above, the washcoat compositions can be
configured and applied in a variety of different ways. The
configurations provide examples of preparing substrates coated with
the washcoats.
General Procedure for Preparation of Washcoats
[1091] The washcoats are made by mixing the solid ingredients with
water. Acetic acid is added to adjust the pH to about 4. The
washcoat slurry is then milled to arrive at an average particle
size of about 4 .mu.m to about 15 .mu.m. The viscosity of the
washcoat is adjusted by mixing with a cellulose solution or with
corn starch to the desired viscosity, typically between about 300
cP to about 1200 cP. The washcoat is aged for about 24 hours to
about 48 hours after cellulose or corn starch addition. The
washcoat is coated onto the substrate by either dip-coating or
vacuum coating. The part(s) to be coated can be optionally
pre-wetted prior to coating. Excess washcoat is blown off and
recycled. The washcoat-coated substrate is then dried at about
25.degree. C. to about 95.degree. C. by flowing air over the coated
part, until the weight levels off. The washcoat-coated substrate is
then calcined at about 450.degree. C. to about 650.degree. C. for
about 1 hour to about 2 hours.
[1092] In one of these configurations, a first washcoat composition
applied to a substrate comprises 3% (or approximately 3%) boehmite,
47% (or approximately 47%) porous alumina (e.g., MI-386 or the
like), and 50% (or approximately 50%) catalytic powder (i.e., the
powder containing the catalytic material), wherein the porous
alumina is impregnated with 15% (or approximately 15%) barium oxide
and the catalytic powder is NNm powder (catalytic nanoparticle on
support nanoparticle on support micro-particle), and a second
washcoat composition comprises 2% (or approximately 2%) boehmite,
83% (or approximately 83%) cerium oxide particles (e.g., HSAS or
the like), and 15% (or approximately 15%) catalytic powder (i.e.,
the powder containing the catalytic material), wherein the cerium
oxide particles are impregnated with 8% (or approximately 8%) BaO
and a mixture of 10:1 (or approximately 10:1) platinum and
palladium, and the catalytic powder is NNm Powder (catalytic
nanoparticle on support nanoparticle on support
micro-particle),
[1093] The ingredients discussed above for the first washcoat
composition are mixed with water and acid, such as acetic acid, and
the pH is adjusted to about 4. After adjusting the viscosity to the
proper levels, this first washcoat is coated onto the substrate.
This first washcoat layer is then dried and calcined. Following
this first washcoating step, a second washcoating step is applied,
where the ingredients discussed above for the second washcoat
composition are mixed with water and acid, such as acetic acid, and
the pH is adjusted to about 4. After adjusting the viscosity to the
proper levels, this second washcoat is coated onto the substrate.
This second washcoat layer is then dried and calcined.
[1094] In another advantageous configuration, a first washcoat
composition applied to a substrate comprises 3% (or approximately
3%) boehmite, 47% (or approximately 47%) porous alumina (e.g.,
MI-386 or the like), and 50% (or approximately 50%) catalytic
powder (i.e., the powder containing the catalytic material),
wherein the porous alumina is impregnated with 15% (or
approximately 15%) barium oxide and the catalytic powder is NNm
powder (catalytic nanoparticle on support nanoparticle on support
micro-particle), a second washcoat composition comprises 3% (or
approximately 3%) boehmite, 17% (or approximately 17%) porous
alumina (e.g., MI-386 or the like), and 80% (or approximately 80%)
catalytic powder (i.e., the powder containing the catalytic
material), wherein the catalytic powder is NNm powder (catalytic
nanoparticle on support nanoparticle on support micro-particle),
and a third washcoat composition comprises 4% (or approximately 4%)
boehmite, 73% (or approximately 73%) cerium oxide particles (e.g.,
HSAS or the like) and 23% (or approximately 23%) catalytic powder
(i.e., the powder containing the catalytic material), wherein the
cerium oxide particles are impregnated with 8% (or approximately
8%) barium oxide and the catalytic powder is NNm powder (catalytic
nanoparticle on support nanoparticle on support
micro-particle).
[1095] The ingredients discussed above for the first washcoat
composition are mixed with water and acid, such as acetic acid, and
the pH is adjusted to about 4. After adjusting the viscosity to the
proper levels, this first washcoat is coated onto the substrate.
This first washcoat layer is then dried and calcined. Following
this first washcoating step, a second washcoating step is applied,
where the ingredients discussed above for the second washcoat
composition are mixed with water and acid, such as acetic acid, and
the pH is adjusted to about 4. After adjusting the viscosity to the
proper levels, this second washcoat is coated onto the substrate.
This second washcoat layer is then dried and calcined. Following
this second washcoating step, a third washcoating step is applied,
where the ingredients discussed above for the third washcoat
composition are mixed with water and acid, such as acetic acid, and
the pH is adjusted to about 4. After adjusting the viscosity to the
proper levels, this third washcoat is coated onto the substrate.
This third washcoat layer is then dried and calcined.
Example 1
Two-Layer Washcoat Configuration-Separate Oxidation and Reduction
Washcoat Layers, Combined Reduction and NO.sub.x Storage Layer
[1096] (a) First Washcoat Composition: Approx. 85 g/L as follows:
[1097] 3% Boehmite; [1098] 47% Porous alumina (MI-386 or the like),
impregnated with 15% BaO; [1099] 50% NNm powder
(nano-on-nano-on-micro particle), the powder that contains Pt, Pd,
or a mixture of Pt/Pd. [1100] (b) Second Washcoat Composition:
Approx. 326 g/L as follows: [1101] 2% Boehmite; [1102] 83% Cerium
oxide (HSAS or the like), impregnated with 8% BaO and 0.6% Pt, Pd,
or a mixture of Pt/Pd; [1103] 15% NNm powder (nano-on-nano-on-micro
particle), the powder that contains Rh.
[1104] Mix the washcoat ingredients from (a) with water and acetic
acid and adjust the pH to about 4. After adjusting the viscosity to
the proper levels, the washcoat is coated onto the substrate with
an approximate layer thickness of 85 g/L. Excess washcoat is blown
off and recycled. This first washcoat layer is then dried and
calcined. Following this first washcoating step, a second
washcoating step is performed: the ingredients from (b) are mixed
with water and acetic acid and the pH adjusted to about 4. After
adjusting the viscosity to the proper levels, the washcoat is
coated onto the substrate with an approximate layer thickness of
326 g/L. Again, excess washcoat is blown off and recycled. This
second washcoat layer is then dried and calcined.
Example 2
Three-layer Washcoat Configuration-Separate Oxidation and Reduction
Washcoat Layers, Separate Reduction and NO.sub.x Storage Layer
[1105] (a) First Washcoat Composition: Approx. 85 g/L as follows:
[1106] 3% Boehmite; [1107] 47% Porous alumina (MI-386 or the like),
impregnated with 15% BaO; [1108] 50% NNm powder
(nano-on-nano-on-micro particle), the powder that contains Pt, Pd,
or a mixture of Pt/Pd. [1109] (b) Second Washcoat Composition:
Approx. 75 g/L as follows: [1110] 3% Boehmite; [1111] 17% Porous
alumina (MI-386 or the like); [1112] 80% NNm powder
(nano-on-nano-on-micro particle), the powder that contains Rh.
[1113] (c) Third Washcoat Composition: Approx. 275 g/L as follows:
[1114] 4% Boehmite; [1115] 73% Cerium oxide (HSAS or the like),
impregnated with 8% BaO; [1116] 23% NNm powder
(nano-on-nano-on-micro particle), the powder that contains Pt, Pd,
or Pt/Pd.
[1117] Mix the washcoat ingredients from (a) with water and acetic
acid and adjust the pH to about 4. After adjusting the viscosity to
the proper levels, the washcoat is coated onto the substrate with
an approximate layer thickness of 85 g/L. Excess washcoat is blown
off and recycled. This first washcoat layer is then dried and
calcined. Following this first washcoating step, a second
washcoating step is performed: the ingredients from (b) are mixed
with water and acetic acid and the pH adjusted to about 4. After
adjusting the viscosity to the proper levels, the washcoat is
coated onto the substrate with an approximate layer thickness of 75
g/L. Again, excess washcoat is blown off and recycled. This second
washcoat layer is then dried and calcined. Following this second
washcoating step, a second washcoating step is performed: the
ingredients from (c) are mixed with water and acetic acid and the
pH adjusted to about 4. After adjusting the viscosity to the proper
levels, the washcoat is coated onto the substrate with an
approximate layer thickness of 275 g/L. Again, excess washcoat is
blown off and recycled. This third washcoat layer is then dried and
calcined.
Example 3
Comparison of Catalytic Converter Performance Described Herein to
Commercially Available Catalytic Converters
[1118] FIG. 4 illustrates the performance of a coated substrate
with reduced PGM in the NO.sub.x storage layer component of a
catalytic converter (indicated as "PGM-reduced LNT"), and a coated
substrate with no PGM in the NO.sub.x storage layer component of a
catalytic converter (indicated as "PGM-free LNT"), where the coated
substrates are prepared according to embodiments of the present
invention, compared to a commercially available catalytic converter
(indicated as "reference"). The catalysts were artificially aged at
750.degree. C. for 25 hours to simulate operation after 125,000
miles in a car.
[1119] The commercially available coated substrate displays a CO
light-off temperature of 113.degree. C. The coated substrate with
the reduced PGM loading in the NO.sub.x storage layer washcoat
displays a CO light-off temperature of 107.degree. C., or about
6.degree. C. lower than the commercially available coated
substrate. The coated substrate with no PGM in the NO.sub.x storage
layer washcoat displays a CO light-off temperature of 121.degree.
C., slightly higher (about 8.degree. C.) than the commercially
available coated substrate.
[1120] The commercially available coated substrate displays a
hydrocarbon light-off temperature of 301.degree. C. The coated
substrate with the reduced PGM loading in the NO.sub.x storage
layer washcoat displays a hydrocarbon light-off temperature of
301.degree. C., comparable to the commercially available coated
substrate. The coated substrate with no PGM in the NO.sub.x storage
layer washcoat displays a hydrocarbon light-off temperature of
282.degree. C., or about 19.degree. C. lower than the commercially
available coated substrate.
Example 4
Comparison of a Coated Substrate with a Three-Layer Washcoat
Configuration to the Euro 6 Standard
[1121] A coated substrate was prepared using a three-layer washcoat
configuration. The composition of the oxidation washcoat layer,
reduction washcoat layer, and NO.sub.x storage layer is detailed
below: [1122] (a) Reductive Washcoat Composition: 75 g/L as
follows: [1123] 20% MI-386 (15 g/L); [1124] 80% NNm powder: Rh
nanoparticles (at a loading of 0.25%) on nano-sized cerium oxide
particles and micron-sized cerium-zirconium-lanthanum oxide
particles (equivalent to a weight percent of 86% cerium oxide, 10%
zirconium oxide and 4% lanthanum oxide) (60 g/L); [1125] (b)
Oxidative Washcoat Composition: 57 g/L as follows: [1126] 26%
MI-386 (15 g/L); [1127] 74% NNm powder: Pt/Pd nanoparticles (10:1
Pt:Pd at a loading of 2.4%) on nano-sized aluminum oxide particles
and micron-sized aluminum oxide particles (MI-386) (42 g/L); [1128]
(c) Storage Layer Washcoat Composition: 263 g/L as follows: [1129]
76% Cerium oxide (HSAS), impregnated with 8% barium acetate (200
g/L); [1130] 24% NNm powder: Pt/Pd nanoparticles (10:1 Pt:Pd at a
loading of 2.4%) on nano-sized aluminum oxide particles and
micron-sized aluminum oxide particles (MI-386) (63 g/L).
[1131] Each washcoat layer additional contained about 3% of
boehmite particles. The three washcoat layers were prepared and
coated on the substrate as described above in Example 2.
[1132] The coated substrate was evaluated using a driving test
(length of 11 km). The total hydrocarbon content (THC) and NO.sub.x
emissions were measured and are presented in FIG. 5 and below in
Table 2. The corresponding THC and NO.sub.x emissions for a
standard commercially available material and the Euro 6 standard
for light-duty diesel are provided for comparison.
TABLE-US-00002 TABLE 2 Comparison of Substrate Coated with
Three-Layer Washcoat Configuration to Euro 6 Light-Duty Diesel
Standard THC NO.sub.x (% relative (% relative THC to Euro 6
NO.sub.x to Euro 6 (mg) standard) (mg) standard) coated substrate
of 462 47 550 63 present example commercial 418 42 506 58 reference
Euro 6 standard 990 100 880 100
[1133] The disclosures of all publications, patents, patent
applications, and published patent applications referred to herein
by an identifying citation are hereby incorporated herein by
reference in their entirety.
[1134] The present invention has been described in terms of
specific embodiments incorporating details to facilitate the
understanding of principles of construction and operation of the
invention. Such reference herein to specific embodiments and
details thereof is not intended to limit the scope of the claims
appended hereto. It will be readily apparent to one skilled in the
art that other various modifications can be made in the embodiments
chosen for illustration without departing from the spirit and scope
of the invention. Therefore, the description and examples should
not be construed as limiting the scope of the invention.
* * * * *