U.S. patent application number 14/960837 was filed with the patent office on 2016-03-24 for systems and methods for zero-pgm binary catalyst having cu, mn, and fe for twc applications.
This patent application is currently assigned to Clean Diesel Technologies, Inc.. The applicant listed for this patent is Stephen J. Golden, Zahra Nazarpoor. Invention is credited to Stephen J. Golden, Zahra Nazarpoor.
Application Number | 20160082422 14/960837 |
Document ID | / |
Family ID | 52810146 |
Filed Date | 2016-03-24 |
United States Patent
Application |
20160082422 |
Kind Code |
A1 |
Nazarpoor; Zahra ; et
al. |
March 24, 2016 |
Systems and Methods for Zero-PGM Binary Catalyst Having Cu, Mn, and
Fe For TWC Applications
Abstract
Variations of bulk powder catalyst material including Cu--Mn,
Cu--Fe, and Fe--Mn spinel systems for ZPGM TWC applications are
disclosed. The disclosed bulk powder catalyst samples include
stoichiometric and non-stoichiometric Cu--Mn, Cu--Fe, and Fe--Mn
spinels on Pr.sub.6O.sub.11--ZrO.sub.2 support oxide, prepared
using incipient wetness method. Activity measurements under
isothermal steady state sweep test condition may be performed under
rich to lean condition. Catalytic activity of samples may be
compared to analyze the influence that different binary spinel
system bulk powders may have on TWC performance of ZPGM materials
for a plurality of TWC applications. Stoichiometric Cu--Mn, Cu--Fe,
and Fe--Mn spinel systems exhibit higher catalytic activity than
non-stoichiometric Cu--Mn, Cu--Fe, and Fe--Mn spinel systems. The
influence of prepared Cu--Mn, Cu--Fe, and Fe--Mn spinel systems may
lead into cost effective manufacturing solutions for ZPGM TWC
systems.
Inventors: |
Nazarpoor; Zahra;
(Camarillo, CA) ; Golden; Stephen J.; (Santa
Barbara, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Nazarpoor; Zahra
Golden; Stephen J. |
Camarillo
Santa Barbara |
CA
CA |
US
US |
|
|
Assignee: |
Clean Diesel Technologies,
Inc.
Oxnard
CA
|
Family ID: |
52810146 |
Appl. No.: |
14/960837 |
Filed: |
December 7, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
14530387 |
Oct 31, 2014 |
9216409 |
|
|
14960837 |
|
|
|
|
13849169 |
Mar 22, 2013 |
8858903 |
|
|
14530387 |
|
|
|
|
Current U.S.
Class: |
502/324 ;
502/331 |
Current CPC
Class: |
B01D 2255/20715
20130101; B01J 23/8892 20130101; Y02T 10/12 20130101; B01J 23/745
20130101; B01D 2255/20738 20130101; B01J 23/005 20130101; B01D
2255/405 20130101; Y02T 10/22 20130101; B01D 2255/65 20130101; Y10S
502/52712 20130101; B01D 2255/2066 20130101; B01D 2255/20761
20130101; B01D 53/945 20130101 |
International
Class: |
B01J 23/889 20060101
B01J023/889; B01J 23/745 20060101 B01J023/745 |
Claims
1. A catalytic system, comprising: a catalyst having the general
formula A.sub.XB.sub.3-XO.sub.4, wherein X may be less than or
equal to 1.5 and wherein A and B are selected from the group
consisting of Cu, Mn, and Fe; and wherein the catalyst is
substantially free of platinum group metals.
2. The catalytic system of claim 1, wherein the catalyst is in
spinel form.
3. The catalytic system of claim 1, wherein the catalyst has the
general formula Cu.sub.XMn.sub.3-XO.sub.4 where
1.0.ltoreq.X.ltoreq.1.5.
4. The catalytic system of claim 1, wherein the catalyst has the
general formula Cu.sub.XFe.sub.3-XO.sub.4 where
0.5.ltoreq.X.ltoreq.1.0.
5. A catalytic system, comprising a catalyst having the general
formula A.sub.XB.sub.3-XO.sub.4, wherein A and B are selected from
the group consisting of Cu, Mn, and Fe.
6. The catalytic system of claim 5, wherein the catalyst is in
spinel form.
7. The catalytic system of claim 5, wherein the catalyst has the
general formula Cu.sub.XMn.sub.3-XO.sub.4 where
1.0.ltoreq.X.ltoreq.1.5.
8. The catalytic system of claim 5, wherein the catalyst has the
general formula Cu.sub.XFe.sub.3-XO.sub.4 where
0.5.ltoreq.X.ltoreq.1.0.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 14/530,387, filed Oct. 31, 2014, entitled
"Methods for Oxidation and Two-way and Three-way ZPGM Catalyst
Systems and Apparatus Comprising Same," now U.S. Pat. No.
9,216,409, issued Dec. 22, 2015, which is a continuation-in-part of
U.S. patent application Ser. No. 13/849,169, filed Mar. 23, 2013,
entitled "Methods for Oxidation and Two-way and Three-way ZPGM
Catalyst Systems and Apparatus Comprising Same," now U.S. Pat. No.
8,858,903, issued Oct. 14, 2014, the entireties of which are
incorporated herein by reference.
BACKGROUND
[0002] 1. Field of the Disclosure
[0003] This disclosure relates generally to catalyst materials, and
more particularly, to binary spinel systems for ZPGM catalysts for
TWC applications.
[0004] 2. Background Information
[0005] Catalysts can have essential attributes of activity,
stability, selectivity, and regenerability in long-term service.
These attributes can be related to the physical and chemical
properties of the catalyst materials, which in turn can be related
to the variable parameters inherent in the method used for the
preparation of the catalyst.
[0006] Catalysts may include active transition metals that may be
added onto a high surface area. By adding multiple metallic
components on the surface of a catalyst, the performance of the
catalyst can be altered. In particular, bimetallic catalysts may
often exhibit improved properties that are not present on either of
the single metal catalysts.
[0007] Generally, TWC systems may include bimetallic catalysts,
which may be based on Platinum group metals (PGMs), including
Pt--Rh, Pt--Pd, Pd--Rh, among others. Although these PGM catalysts
may be effective for toxic emission control and have been
commercialized in industry, PGM materials are expensive. This high
cost remains a critical factor for wide spread applications of
these catalysts. One possible alternative may be use of Zero-PGM
catalysts, which are abundant and less expensive than PG Ms.
[0008] According to the foregoing reasons, there may be a need to
provide material compositions for Zero-PGM catalyst systems for
cost effective manufacturing, using a plurality of material
compositions for suitable Zero-PGM catalyst, that can be used in a
variety of environments and TWC applications.
SUMMARY
[0009] The present disclosure may provide material compositions
including a plurality of binary spinel compositions on doped
Zirconia support oxide to develop suitable ZPGM catalysts for TWC
applications.
[0010] According to embodiments in present disclosure, catalyst
samples may be prepared using variations of Cu--Mn, Cu--Fe, and
Fe--Mn stoichiometric and non-stoichiometric spinels on doped
Zirconia support oxide, which may be converted into bulk powder
format by incipient wetness (IW) method, as known in the art, of
spinel systems aqueous solution on doped Zirconia support oxide
powder. Stoichiometric and non-stoichiometric binary spinel
structures may be prepared at different molar ratios according to
general formulation A.sub.XB.sub.3-XO.sub.4, where X may be
variable of different molar ratios within a range from about 0 to
about 1.5 and A and B can be Cu, Mn, and Fe. In present disclosure,
disclosed Cu--Mn, Cu--Fe, and Fe--Mn spinel systems may be
supported on Praseodymium-Zirconia support oxide powders, which may
be subsequently dried, calcined, and ground to bulk powder.
[0011] The NO/CO cross over R-value of bulk powder catalyst
samples, per binary spinel systems in present disclosure, may be
determined by performing isothermal steady state sweep test. The
isothermal steady state sweep test may be carried out at a selected
inlet temperature using an 11-point R-value from rich condition to
lean condition at a plurality of space velocities. Results from
isothermal steady state sweep test may be compared to show the
influence that different binary spinel system bulk powders may have
on TWC performance, particularly under rich condition close to
stoichiometric condition. Additionally, catalytic performance of
bulk powder samples including Cu--Mn, Cu--Fe, and Fe--Mn spinels
may be qualitatively compared separately for each group of binary
spinel systems. According to principles in present disclosure, the
binary spinel system in each group, which shows high level of
activity, may be compared with binary spinel systems from other
groups also showing high level of activity to analyze influence on
TWC performance for overall improvements on catalyst
manufacturing.
[0012] According to principles in present disclosure, comparison of
bulk powder catalyst samples showing the most effective TWC
performance may be used for a plurality of TWC applications.
Catalyst samples in the other groups which may show significant TWC
performance, may also be made available for utilization as bulk
powder catalyst materials for the manufacturing of ZPGM catalysts
for TWC applications.
[0013] Numerous other aspects, features, and benefits of the
present disclosure may be made apparent from the following detailed
description taken together with the drawing figures, which may
illustrate the embodiments of the present disclosure, incorporated
herein for reference.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The present disclosure can be better understood by referring
to the following figures. The components in the figures are not
necessarily to scale, emphasis instead being place upon
illustrating the principles of the disclosure. In the figures,
reference numerals designate corresponding parts throughout the
different views.
[0015] FIG. 1 shows catalyst performance for bulk powder catalyst
samples of Cu--Mn spinels on doped Zirconia support oxide, under
isothermal steady state sweep condition, at inlet temperature of
about 450.degree. C. and space velocity (SV) of about 40,000
h.sup.-1, according to an embodiment. FIG. 1A shows TWC activity
for stoichiometric Cu--Mn spinel on doped Zirconia support oxide.
FIG. 1B depicts comparison of NO.sub.X conversion levels for
stoichiometric and non-stoichiometric Cu--Mn spinels on doped
Zirconia support oxide.
[0016] FIG. 2 illustrates catalyst performance for bulk powder
catalyst samples of stoichiometric Cu--Fe spinel on doped Zirconia
support oxide, under isothermal steady state sweep condition, at
inlet temperature of about 450.degree. C. and SV of about 40,000
h.sup.-1, according to an embodiment.
[0017] FIG. 3 depicts catalyst performance comparison for bulk
powder catalyst samples of stoichiometric and non-stoichiometric
Cu--Fe spinels on doped Zirconia support oxide, under isothermal
steady state sweep condition, at inlet temperature of about
450.degree. C. and SV of about 40,000 h.sup.4, according to an
embodiment. FIG. 3A shows comparison of HC conversion levels for
stoichiometric and non-stoichiometric Cu--Fe spinels on doped
Zirconia support oxide. FIG. 3B illustrates comparison of NO.sub.X
conversion levels for stoichiometric and non-stoichiometric Cu--Fe
spinels on doped Zirconia support oxide.
[0018] FIG. 4 shows catalyst performance for bulk powder catalyst
samples of stoichiometric Fe--Mn spinel on doped Zirconia support
oxide, under isothermal steady state sweep condition, at inlet
temperature of about 450.degree. C. and SV of about 40,000
h.sup.-1, according to an embodiment.
[0019] FIG. 5 illustrates catalyst performance comparison for bulk
powder catalyst samples of stoichiometric and non-stoichiometric
Fe--Mn spinels on doped Zirconia support oxide, under isothermal
steady state sweep condition, at inlet temperature of about
450.degree. C. and SV of about 40,000 h.sup.-1, according to an
embodiment. FIG. 5A shows comparison of HC conversion levels for
stoichiometric and non-stoichiometric Fe--Mn spinels on doped
Zirconia support oxide. FIG. 5B illustrates comparison of NO.sub.X
conversion levels for stoichiometric and non-stoichiometric Fe--Mn
spinels on doped Zirconia support oxide.
[0020] FIG. 6 depicts catalyst performance comparison for bulk
powder catalyst samples of stoichiometric Cu--Mn, Cu--Fe and Fe--Mn
spinels on doped Zirconia support oxide, under isothermal steady
state sweep condition, at inlet temperature of about 450.degree. C.
and SV of about 40,000 h.sup.-1, according to an embodiment. FIG.
6A shows comparison of HC conversion levels for stoichiometric
Cu--Mn, Cu--Fe and Fe--Mn spinels on doped Zirconia support oxide.
FIG. 6B illustrates comparison of NO.sub.X conversion levels for
stoichiometric Cu--Mn, Cu--Fe and Fe--Mn spinels on doped Zirconia
support oxide.
DETAILED DESCRIPTION
[0021] The present disclosure is here described in detail with
reference to embodiments illustrated in the drawings, which form a
part here. Other embodiments may be used and/or other changes may
be made without departing from the spirit or scope of the present
disclosure. The illustrative embodiments described in the detailed
description are not meant to be limiting of the subject matter
presented here.
DEFINITIONS
[0022] As used here, the following terms may have the following
definitions:
[0023] "Platinum group Metal (PGM)" refers to platinum, palladium,
ruthenium, iridium, osmium, and rhodium.
[0024] "Zero platinum group (ZPGM) catalyst" refers to a catalyst
completely or substantially free of platinum group metals.
[0025] "Catalyst" refers to one or more materials that may be of
use in the conversion of one or more other materials.
[0026] "Incipient wetness (IW)" refers to the process of adding
solution of catalytic material to a dry support oxide powder until
all pore volume of support oxide is filled out with solution and
mixture goes slightly near saturation point.
[0027] "Calcination" refers to a thermal treatment process applied
to solid materials, in presence of air, to bring about a thermal
decomposition, phase transition, or removal of a volatile fraction
at temperatures below the melting point of the solid materials.
[0028] "Milling" refers to the operation of breaking a solid
material into a desired grain or particle size.
[0029] "Treating, treated, or treatment" refers to drying, firing,
heating, evaporating, calcining, or mixtures thereof.
[0030] "Spinel" refers to any of various mineral oxides of
magnesium, iron, zinc, or manganese in combination with aluminum,
chromium, copper or iron with AB.sub.2O.sub.4 structure.
[0031] "Conversion" refers to the chemical alteration of at least
one material into one or more other materials.
[0032] "R-value" refers to the number obtained by dividing the
reducing potential by the oxidizing potential of materials in a
catalyst.
[0033] "Rich condition" refers to exhaust gas condition with an
R-value above 1.
[0034] "Lean condition" refers to exhaust gas condition with an
R-value below 1.
[0035] "Air/Fuel ratio" or "A/F ratio" refers to the weight of air
divided by the weight of fuel.
[0036] "Three-way catalyst (TWC)" refers to a catalyst that may
achieve three simultaneous tasks: reduce nitrogen oxides to
nitrogen and oxygen, oxidize carbon monoxide to carbon dioxide, and
oxidize unburnt hydrocarbons to carbon dioxide and water.
DESCRIPTION OF THE DRAWINGS
[0037] The present disclosure may provide bulk powder material
compositions including Cu--Mn, Cu--Fe, and Fe--Mn spinels on a
plurality of support oxides to develop suitable ZPGM catalyst
materials capable of providing high chemical reactivity and thermal
stability. Aspects that may be treated in present disclosure may
show catalytic conversion capacity or recombination rates of a
plurality of binary spinel system bulk powders and the influence on
TWC performance.
[0038] Bulk Powder ZPGM Catalyst Material Composition and
Preparation
[0039] The disclosed Zero-PGM material compositions in form of bulk
powder in the present disclosure may be prepared from
stoichiometric and non-stoichiometric binary spinels of Cu--Mn,
Cu--Fe, and Fe--Mn at different molar ratios. All binary spinels
may be supported on a plurality of support oxides, in present
disclosure preferably on doped Zirconia support oxide, via
incipient wetness (IW) method as known in the art.
[0040] Preparation of bulk powder catalyst samples may begin by
preparing the binary solution for Cu--Mn, Cu--Fe, and Fe--Mn
spinels to make aqueous solution. Binary solutions of Cu--Mn,
Cu--Fe, and Fe--Mn may be prepared by mixing the appropriate amount
of Mn nitrate solution (Mn(NO.sub.3).sub.2), Cu nitrate solution
(CuNO.sub.3), and Fe nitrate solution (Fe(NO.sub.3).sub.3) with
water to make solution at different molar ratios according to
general formulations in Table 1, where disclosed binary spinel
systems in present disclosure are shown. Accordingly, solution of
Cu--Mn, Cu--Fe, and Fe--Mn nitrates may be subsequently added
drop-wise to doped Zirconia support oxide powder via IW method.
Then, mixtures of Cu--Mn, Cu--Fe, and Fe--Mn binary spinels on
doped Zirconia may be dried at 120.degree. C. over night and
calcined at a plurality of temperatures. In present disclosure,
calcination may be performed at about 800.degree. C. for about 5
hours. Subsequently, calcined materials of Cu--Mn, Cu--Fe, and
Fe--Mn binary spinels on doped Zirconia may be ground to fine grain
bulk powder.
TABLE-US-00001 TABLE 1 System Elements Composition Binary Cu--Mn
Cu.sub.XMn.sub.3-XO.sub.4 1 .ltoreq. X .ltoreq. 1.5 Cu--Fe
Cu.sub.XFe.sub.3-XO.sub.4 0.5 .ltoreq. X .ltoreq. 1 Fe--Mn
Fe.sub.XMn.sub.3-XO.sub.4 0 .ltoreq. X .ltoreq. 1.5
[0041] Bulk powder catalyst samples may be then prepared for
testing under isothermal steady state sweep condition to determine
and analyze TWC performance resulting for each catalyst sample
including stoichiometric and non-stoichiometric Cu--Mn, Cu--Fe,
Fe--Mn binary spinels on doped Zirconia support oxide.
[0042] The NO/CO cross over R-value of bulk powder catalyst
samples, per disclosed binary spinels, may be determined by
performing isothermal steady state sweep test.
[0043] Results from isothermal steady state sweep test may be
compared to show the influence that different binary spinel system
bulk powders may have on TWC performance, particularly under rich
condition close to stoichiometric condition. Additionally,
catalytic performance of bulk powder samples including
stoichiometric and non-stoichiometric Cu--Mn, Cu--Fe, and Fe--Mn
spinels on doped Zirconia support oxide may be qualitatively
compared.
[0044] According to principles in present disclosure, the binary
spinel system in each group, which shows high level of activity,
may be compared with binary spinel systems from other groups also
showing high level of activity to analyze influence on TWC
performance for overall improvements that may be developed in the
preparation of bulk powder catalyst material to use for ZPGM
catalyst for TWC applications.
[0045] Isothermal Steady State Sweep Test Procedure
[0046] The isothermal steady state sweep test may be done employing
a flow reactor at inlet temperature of about 450.degree. C., and
testing a gas stream at 11-point R-values from about 2.0 (rich
condition) to about 0.8 (lean condition) to measure the CO, NO, and
HC conversions. In present disclosure, gas stream may be tested at
R-values from about 1.6 (rich condition) to about 0.9 (lean
condition) to measure the CO, NO, and HC conversions.
[0047] The space velocity (SV) in the isothermal steady state sweep
test may be adjusted at about 40,000 h.sup.-1. The gas feed
employed for the test may be a standard TWC gas composition, with
variable O.sub.2 concentration in order to adjust R-value from rich
condition to lean condition during testing. The standard TWC gas
composition may include about 8,000 ppm of CO, about 400 ppm of
C.sub.3H.sub.6, about 100 ppm of C.sub.3H.sub.8, about 1,000 ppm of
NO.sub.X, about 2,000 ppm of H.sub.2, about 10% of CO.sub.2, and
about 10% of H.sub.2O. The quantity of O.sub.2 in the gas mix may
be varied to adjust Air/Fuel (A/F) ratio within the range of
R-values to test the gas stream.
[0048] The following examples are intended to illustrate the scope
of the disclosure. It is to be understood that other procedures
known to those skilled in the art may alternatively be used.
EXAMPLES
Example #1
Stoichiometric and Non-Stoichiometric Cu--Mn Spinels on
Pr.sub.6O.sub.11--ZrO.sub.2 Support Oxide
[0049] Example #1 may illustrate preparation of bulk powder
catalyst samples from stoichiometric and non-stoichiometric Cu--Mn
spinels supported on Pr.sub.6O.sub.11--ZrO.sub.2 support oxide via
IW method with general formulation of Cu.sub.XMn.sub.3-XO.sub.4
where 1.0.ltoreq.X.ltoreq.1.5.
[0050] Preparation of bulk powder catalyst samples may begin by
preparing the Cu--Mn solution by mixing the appropriate amount of
Cu nitrate solution (CuNO.sub.3) and Mn nitrate solution
(Mn(NO.sub.3).sub.2) with water to make solution at different molar
ratios according to formulation in Table 2, where disclosed
stoichiometric and non-stoichiometric Cu--Mn spinel systems are
shown. Then, solution of Cu--Mn nitrates may be added drop-wise to
Pr.sub.6O.sub.11--ZrO.sub.2 support oxide powder via IW method.
Subsequently, mixture of Cu--Mn spinel on
Pr.sub.6O.sub.11--ZrO.sub.2 support oxide may be dried at
120.degree. C. over night and calcined at about 800.degree. C. for
5 hours, and then ground to fine grain bulk powder.
TABLE-US-00002 TABLE 2 Binary spinel Composition Cu--Mn
CuMn.sub.2O.sub.4 Cu.sub.1.5Mn.sub.1.5O.sub.4
[0051] In example #1, the performance of bulk powder catalyst
samples may be determined by performing isothermal steady state
sweep test at about 450.degree. C., and testing a gas stream at
R-values from about 2.0 (rich condition) to about 0.8 (lean
condition) to measure the CO, NO, and HC conversions. SV in the
isothermal steady state sweep test may be adjusted at about 40,000
h.sup.-1. In present disclosure, NO conversion, CO conversion, and
HC conversion from prepared bulk powder samples of stoichiometric
and non-stoichiometric Cu--Mn spinels may be measured/analyzed from
about 1.6 (rich condition) to about 0.9 (lean condition).
[0052] FIG. 1 shows catalyst performance 100 for bulk powder
catalyst samples prepared per example #1, under isothermal steady
state sweep condition, at inlet temperature of about 450.degree. C.
and SV of about 40,000 h.sup.-1, according to an embodiment.
[0053] In FIG. 1A, conversion curve 102 (solid line with square),
conversion curve 104 (solid line with triangle), and conversion
curve 106 (solid line with circle) respectively show isothermal
steady state sweep test results for NO conversion, CO conversion,
and HC conversion for bulk powder catalyst samples including
stoichiometric Cu.sub.1.0Mn.sub.2.0O.sub.4 spinel.
[0054] As may be seen in FIG. 1A, for bulk powder catalyst samples
including stoichiometric Cu.sub.1.0Mn.sub.2.0O.sub.4 spinel, NO/CO
cross over R-value takes place at the specific R-value of 1.4,
where NO.sub.X and CO conversions are about 100%, respectively.
Activity for bulk powder catalyst samples including stoichiometric
Cu.sub.1.0Mn.sub.2.0O.sub.4 spinel may be observed at R-value of
1.1. At this R-value, HC and NO.sub.X conversions are about 94.3%
and 81.1%, respectively. CO conversion is 100% at entire R-value
region.
[0055] In FIG. 1B, conversion curve 108 (long dash line) and
conversion curve 110 (solid line) respectively show steady state
sweep test results for NO conversion comparison for bulk powder
catalyst samples including Cu.sub.1.0Mn.sub.2.0O.sub.4 and
Cu.sub.15Mn.sub.15O.sub.4 spinels. As may be seen, comparison of
results of NO.sub.X conversion indicates that bulk powder catalyst
samples including stoichiometric Cu.sub.1.0Mn.sub.2.0O.sub.4 spinel
show higher catalytic activity than bulk powder catalyst samples
including non-stoichiometric Cu.sub.15Mn.sub.15O.sub.4 spinel.
Example #2
Stoichiometric and Non-Stoichiometric Cu--Fe Spinels on
Pr.sub.6O.sub.11--ZrO.sub.2 Support Oxide
[0056] Example #2 may illustrate preparation of bulk powder
catalyst samples from stoichiometric and non-stoichiometric Cu--Fe
spinels supported on Pr.sub.6O.sub.11--ZrO.sub.2 support oxide via
IW method with general formulation of Cu.sub.XFe.sub.3-XO.sub.4
where 0.5.ltoreq.X.ltoreq.1.0.
[0057] Preparation of bulk powder catalyst samples may begin by
preparing the Cu--Fe solution by mixing the appropriate amount of
Cu nitrate solution (CuNO.sub.3) and Fe nitrate solution
(Fe(NO.sub.3).sub.3) with water to make solution at different molar
ratios according to formulation in Table 3, where disclosed
stoichiometric and non-stoichiometric Cu--Fe spinel systems are
shown. Then, solution of Cu--Fe nitrates may be added drop-wise to
Pr.sub.6O.sub.11--ZrO.sub.2 support oxide powder via IW method.
Subsequently, mixture of Cu--Fe spinel on
Pr.sub.6O.sub.11--ZrO.sub.2 support oxide may be dried at
120.degree. C. over night and calcined at about 800.degree. C. for
5 hours, and then ground to fine grain bulk powder.
TABLE-US-00003 TABLE 3 Binary spinel Composition Cu--Fe
CuFe.sub.2O.sub.4 Cu.sub.1.5Fe.sub.2.5O.sub.4
Cu.sub.0.5Fe.sub.2.5O.sub.4
[0058] In example #2, the performance of bulk powder catalyst
samples may be determined by performing isothermal steady state
sweep test at about 450.degree. C., and testing a gas stream at
R-values from about 2.0 (rich condition) to about 0.8 (lean
condition) to measure the CO, NO, and HC conversions. SV in the
isothermal steady state sweep test may be adjusted at about 40,000
h.sup.-1. In present disclosure, NO conversion, CO conversion, and
HC conversion from prepared bulk powder samples of stoichiometric
and non-stoichiometric Cu--Fe spinels may be measured/analyzed from
about 1.6 (rich condition) to about 0.9 (lean condition).
[0059] FIG. 2 illustrates catalyst performance 200 for bulk powder
catalyst samples prepared per example #2, under isothermal steady
state sweep condition, at inlet temperature of about 450.degree. C.
and SV of about 40,000 h.sup.-1, according to an embodiment.
[0060] In FIG. 2, conversion curve 202 (solid line with square),
conversion curve 204 (solid line with triangle), and conversion
curve 206 (line with solid circle) respectively illustrate
isothermal steady state sweep test results for NO conversion, CO
conversion, and HC conversion for bulk powder catalyst samples
including stoichiometric Cu.sub.1.0Fe.sub.2.0O.sub.4 spinel.
[0061] As may be seen in FIG. 2, for bulk powder catalyst samples
including stoichiometric Cu.sub.1.0Fe.sub.2.0O.sub.4 spinel, NO/CO
cross over R-value takes place at the specific R-value of 1.60,
where NO.sub.X and CO conversions are about 100%, respectively.
Activity for bulk powder catalyst samples including stoichiometric
Cu.sub.1.0Fe.sub.2.0O.sub.4 spinel may be observed at R-value of
1.1. At this R-value, HC and NO.sub.X conversions are about 86.2%
and about 56.8%, respectively. CO conversion is 100% at entire
R-value region.
[0062] FIG. 3 depicts catalyst performance comparison 300 for bulk
powder catalyst samples per example #2, under isothermal steady
state sweep condition, at inlet temperature of about 450.degree. C.
and SV of about 40,000 h.sup.-1, according to an embodiment.
[0063] In FIG. 3A, conversion curve 302 (dot line), conversion
curve 304 (solid line), and conversion curve 306 (long dash line)
respectively depict steady state sweep test results for HC
conversion comparison for bulk powder catalyst samples including
Cu.sub.1.0Fe.sub.2.0O.sub.4, Cu.sub.1.5Fe.sub.1.5O.sub.4, and
Cu.sub.0.5Fe.sub.2.5O.sub.4 spinels. As may be seen, comparison of
results of HC conversion indicates that bulk powder catalyst
samples including stoichiometric Cu.sub.1.0Fe.sub.2.0O.sub.4 spinel
show higher HC conversion than bulk powder catalyst samples
including non-stoichiometric Cu.sub.1.5Fe.sub.1.5O.sub.4 and
Cu.sub.0.5Fe.sub.2.5O.sub.4 spinels under lean and rich
condition.
[0064] In FIG. 3B, conversion curve 308 (dot line), conversion
curve 310 (solid line), and conversion curve 312 (long dash line)
respectively depict steady state sweep test results for NO
conversion comparison for bulk powder catalyst samples including
Cu.sub.1.0Fe.sub.2.0O.sub.4, Cu.sub.1.5Fe.sub.1.5O.sub.4, and
Cu.sub.0.5Fe.sub.2.5O.sub.4 spinels. A comparison of results of
NO.sub.X conversion for bulk powder catalyst samples including
Cu.sub.1.0Fe.sub.2.0O.sub.4, Cu.sub.1.5Fe.sub.1.5O.sub.4, and
Cu.sub.0.5Fe.sub.2.5O.sub.4 spinels indicates that decreasing Cu
concentration in the spinel structure to X<1.0 may reduce
NO.sub.X conversion as may be seen in FIG. 3B with significant
lower NO.sub.X conversion for Cu.sub.0.5Fe.sub.2.5O.sub.4.
Example #3
Stoichiometric and Non-Stoichiometric Fe--Mn Spinels on
Pr.sub.6O.sub.11--ZrO.sub.2 Support Oxide
[0065] Example #3 may illustrate preparation of bulk powder
catalyst samples from stoichiometric and non-stoichiometric Fe--Mn
spinels supported on Pr.sub.6O.sub.11--ZrO.sub.2 support oxide via
IW method with general formulation of Fe.sub.XMn.sub.3-XO.sub.4
where 0.ltoreq.X.ltoreq.1.5.
[0066] Preparation of bulk powder catalyst samples may begin by
preparing the Fe--Mn solution by mixing the appropriate amount of
Fe nitrate solution (Fe(NO.sub.3).sub.3) and Mn nitrate solution
(Mn(NO.sub.3).sub.2) with water to make solution at different molar
ratios according to formulation in Table 4, where disclosed
stoichiometric and non-stoichiometric Fe--Mn spinel systems are
shown. Then, solution of Fe--Mn nitrates may be added drop-wise to
Pr.sub.6O.sub.11--ZrO.sub.2 support oxide powder via IW method.
Subsequently, mixture of Fe--Mn spinel on
Pr.sub.6O.sub.11--ZrO.sub.2 support oxide may be dried at
120.degree. C. over night and calcined at about 800.degree. C. for
5 hours, and then ground to fine grain bulk powder.
TABLE-US-00004 TABLE 4 Binary spinel Composition Fe--Mn
FeMn.sub.2O.sub.4 Fe.sub.0.5Mn.sub.2.4O.sub.4
Fe.sub.1.2Mn.sub.1.8O.sub.4 Mn.sub.3O.sub.4
[0067] In example #3, the performance of bulk powder catalyst
samples may be determined by performing isothermal steady state
sweep test at about 450.degree. C., and testing a gas stream at
R-values from about 2.0 (rich condition) to about 0.8 (lean
condition) to measure the CO, NO, and HC conversions. SV in the
isothermal steady state sweep test may be adjusted at about 40,000
h.sup.-1. In present disclosure, NO conversion, CO conversion, and
HC conversion from prepared bulk powder samples of stoichiometric
and non-stoichiometric Fe--Mn spinels may be measured/analyzed from
about 1.6 (rich condition) to about 0.9 (lean condition).
[0068] FIG. 4 shows catalyst performance 400 for bulk powder
catalyst samples prepared per example #3, under isothermal steady
state sweep condition, at inlet temperature of about 450.degree. C.
and SV of about 40,000 h.sup.-1, according to an embodiment.
[0069] In FIG. 4, conversion curve 402 (solid line with square),
conversion curve 404 (solid line with triangle), and conversion
curve 406 (solid line with circle) respectively show isothermal
steady state sweep test results for NO conversion, CO conversion,
and HC conversion for bulk powder catalyst samples including
stoichiometric Fe.sub.1.0Mn.sub.2.0O.sub.4 spinel.
[0070] As may be seen in FIG. 4, for bulk powder catalyst samples
including stoichiometric Fe.sub.1.0Mn.sub.2.0O.sub.4 spinel, NO/CO
cross over R-value does not occur. Activity for bulk powder samples
including stoichiometric Fe.sub.1.0Mn.sub.2.0O.sub.4 spinel may be
observed at R-value of 1.1. At this R-value, HC and NO.sub.X
conversions are about 92.9% and 13.8%, respectively. CO conversion
is 100% at entire R-value region. It may be also noted that lower
NO.sub.X conversion may be due to the absence of Cu in the spinel
structure.
[0071] FIG. 5 illustrate catalyst performance comparison 500 for
bulk powder catalyst samples per example #3, under isothermal
steady state sweep condition, at inlet temperature of about
450.degree. C. and SV of about 40,000 h.sup.-1, according to an
embodiment.
[0072] In FIG. 5A, conversion curve 502 (solid line), conversion
curve 504 (long dash dot line), conversion curve 506 (dot line),
and conversion curve 508 (dash line) respectively illustrate
isothermal steady state sweep test results for HC conversion
comparison for bulk powder catalyst samples including
Fe.sub.1.0Mn.sub.2.0O.sub.4, Fe.sub.0.6Mn.sub.2.4O.sub.4,
Fe.sub.1.2Mn.sub.1.8O.sub.4, and Mn.sub.3O.sub.4 spinels.
[0073] As may be seen in FIG. 5A, bulk powder catalyst samples
including stoichiometric Fe.sub.1.0Mn.sub.2.0O.sub.4 spinel may
show higher catalytic activity in HC conversion than bulk powder
catalyst samples including non-stoichiometric
Fe.sub.0.6Mn.sub.2.4O.sub.4, Fe.sub.1.2Mn.sub.1.8O.sub.4, and
Mn.sub.3O.sub.4 spinels.
[0074] In FIG. 5B, conversion curve 510 (solid line), conversion
curve 512 (long dash dot line), conversion curve 514 (dot line),
and conversion curve 516 (dash line) respectively depict isothermal
steady state sweep test results for NO conversion comparison for
bulk powder samples including Fe.sub.1.0Mn.sub.2.0O.sub.4,
Fe.sub.0.6Mn.sub.2.4O.sub.4, Fe.sub.1.2Mn.sub.1.8O.sub.4, and
Mn.sub.3O.sub.4 spinels.
[0075] As may be seen in FIG. 5B, bulk powder catalyst samples
including stoichiometric and non-stoichiometric Fe--Mn spinel
systems may show in overall low NO.sub.X activity. Additionally, no
NO.sub.X conversion occurs when Fe is zero as shown in conversion
curve 516, which corresponds to Mn.sub.3O.sub.4 spinel. By
increasing Fe content, NO.sub.X conversion improves.
[0076] Results observed for NO.sub.X and HC conversions indicate
that bulk powder catalyst samples including stoichiometric
Fe.sub.1.0Mn.sub.2.0O.sub.4 spinel show higher catalytic activity
than bulk powder catalyst samples including non-stoichiometric
Fe.sub.0.6Mn.sub.2.4O.sub.4, Fe.sub.1.2Mn.sub.1.8O.sub.4, and
Mn.sub.3O.sub.4 spinels. Additionally, bulk powder catalyst
materials including stoichiometric and non-stoichiometric Fe--Mn
spinel systems may be employed as oxidation catalyst materials for
HC/CO activity since low NO.sub.X activity may be observed.
[0077] Comparison of Stoichiometric Cu--Mn, Cu--Fe, and Fe--Mn
Spinels on Pr.sub.6O.sub.11--ZrO.sub.2 Support Oxide
[0078] FIG. 6 depicts catalyst performance comparison 600 for bulk
powder catalyst samples of stoichiometric Cu--Mn, Cu--Fe and Fe--Mn
spinels supported on ZrO.sub.2--Pr.sub.6O.sub.11, under isothermal
steady state sweep condition, at inlet temperature of about
450.degree. C. and SV of about 40,000 h.sup.-1, according to an
embodiment.
[0079] In FIG. 6A, conversion curve 602 (solid line), conversion
curve 604 (long dash dot line), and conversion curve 606 (dot line)
respectively show isothermal steady state sweep test results for HC
conversion comparison for bulk powder catalyst samples including
stoichiometric Cu.sub.1.0Mn.sub.2.0O.sub.4,
Cu.sub.1.0Fe.sub.2.0O.sub.4, and Fe.sub.1.0Mn.sub.2O.sub.4
spinels.
[0080] As may be seen in FIG. 6A, bulk powder catalyst samples
including stoichiometric Fe.sub.1.0Mn.sub.2.0O.sub.4 spinels show
highest catalytic activity in HC conversion than bulk powder
catalyst samples including stoichiometric
Cu.sub.1.0Mn.sub.2.0O.sub.4 and Cu.sub.1.0Fe.sub.2.0O.sub.4
spinels, while Cu.sub.1.0Fe.sub.2.0O.sub.4 spinel shows lowest HC
conversion. CO conversion is 100% for all samples under entire
R-value region.
[0081] In FIG. 6B, conversion curve 608 (solid line), conversion
curve 610 (long dash dot line), and conversion curve 612 (dot line)
respectively illustrate isothermal steady state sweep test results
for NO conversion comparison for bulk powder samples including
stoichiometric Cu.sub.1.0Mn.sub.2.0O.sub.4,
Cu.sub.1.0Fe.sub.2.0O.sub.4, and Fe.sub.1.0Mn.sub.2.0O.sub.4
spinels.
[0082] As may be seen in FIG. 6B, bulk powder catalyst samples
including stoichiometric Cu.sub.1.0Mn.sub.2.0O.sub.4 show highest
catalytic performance in NO.sub.X conversion than bulk powder
catalyst samples including stoichiometric Cu.sub.1.0Fe.sub.2O.sub.4
and Fe.sub.1.0Mn.sub.2O.sub.4 spinels, while
Fe.sub.1.0Mn.sub.2.0O.sub.4 spinel shows lowest NO.sub.X
conversion, thus indicating the presence of Cu as key element for
improvement of NO.sub.X conversion.
[0083] In present disclosure, all stoichiometric Cu--Mn, Cu--Fe,
and Fe--Mn spinel systems show higher activity than
non-stoichiometric Cu--Mn, Cu--Fe, and Fe--Mn spinel systems. As
may be observed, stoichiometric and non-stoichiometric binary
spinel systems not including Cu may show low or no NO.sub.X
activity. Cu may be the main element influencing NO.sub.X
conversion. Additionally, bulk powder catalyst material including
Mn.sub.3O.sub.4 oxide may show no influence in NO.sub.X conversion
when not in composition with another non-PGM material. Bulk powder
catalyst materials including stoichiometric and non-stoichiometric
Fe--Mn spinel systems may be employed as oxidation catalyst
materials for HC/CO activity. Also, bulk powder catalyst samples
including stoichiometric Cu--Mn spinel system exhibits higher
NO.sub.X conversion than bulk powder catalyst samples including
stoichiometric Cu--Fe spinel system, which shows NO.sub.X
conversion level higher than bulk powder catalyst samples including
stoichiometric Fe--Mn spinel system. It may also be noted in
present disclosure that CO conversion is about 100% for all
disclosed stoichiometric and non-stoichiometric binary spinel
systems.
[0084] Bulk powder catalyst samples including stoichiometric and
non-stoichiometric Cu--Mn, Cu--Fe, and Fe--Mn spinel systems on
Pr.sub.6O.sub.11--ZrO.sub.2 support oxide powder may exhibit
suitable TWC performance when employed in ZPGM catalysts for a
plurality of TWC applications, leading to a more effective
utilization of ZPGM catalyst materials in TWC converters.
[0085] While various aspects and embodiments have been disclosed,
other aspects and embodiments may be contemplated. The various
aspects and embodiments disclosed here are for purposes of
illustration and are not intended to be limiting, with the true
scope and spirit being indicated by the following claims.
* * * * *