U.S. patent application number 12/215694 was filed with the patent office on 2009-12-31 for zero platinum group metal catalysts.
Invention is credited to Stephen J. Golden, Randal Hatfield, Johnny Ngo, Jason Pless, Mann Sakbodin.
Application Number | 20090324468 12/215694 |
Document ID | / |
Family ID | 41444842 |
Filed Date | 2009-12-31 |
United States Patent
Application |
20090324468 |
Kind Code |
A1 |
Golden; Stephen J. ; et
al. |
December 31, 2009 |
Zero platinum group metal catalysts
Abstract
The present invention pertains to catalyst systems for nitrogen
oxide, carbon monoxide, hydrocarbon, and sulfur reactions that are
free or substantially free of platinum group metals. The catalyst
system of the present invention comprise a substrate and a
washcoat, wherein the washcoat comprises at least one oxide solid,
wherein the oxide solid comprises one or more selected from the
group consisting of a carrier material oxide, a catalyst, and
mixtures thereof. The catalyst system may optionally have an
overcoat, wherein the overcoat comprises at least one oxide solid,
wherein the oxide solid comprises one or more selected from the
group consisting of a carrier material oxide, a catalyst, and
mixtures thereof. The catalyst comprises one or more selected from
the group consisting of a ZPGM transition metal catalyst, a mixed
metal oxide catalyst, a zeolite catalysts, or mixtures thereof.
Inventors: |
Golden; Stephen J.; (Santa
Barbara, CA) ; Hatfield; Randal; (Oxnard, CA)
; Pless; Jason; (Ventura, CA) ; Ngo; Johnny;
(Oxnard, CA) ; Sakbodin; Mann; (Thousand Oaks,
CA) |
Correspondence
Address: |
REED SMITH LLP
2500 ONE LIBERTY PLACE, 1650 MARKET STREET
PHILADELPHIA
PA
19103
US
|
Family ID: |
41444842 |
Appl. No.: |
12/215694 |
Filed: |
June 27, 2008 |
Current U.S.
Class: |
423/210 ; 502/1;
502/100; 502/226; 502/232; 502/304; 502/319; 502/320; 502/321;
502/322; 502/324; 502/331; 502/332; 502/335; 502/336; 502/337;
502/338; 502/340; 502/341; 502/346; 502/348; 502/349; 502/350;
502/352; 502/353; 502/354; 502/355; 502/60 |
Current CPC
Class: |
B01J 35/1014 20130101;
Y02T 10/12 20130101; B01J 23/83 20130101; B01J 2523/00 20130101;
B01J 35/1038 20130101; B01J 23/755 20130101; B01D 2255/20715
20130101; Y02T 10/22 20130101; B01J 37/0219 20130101; B01J 21/005
20130101; B01J 23/002 20130101; B01J 35/1042 20130101; B01J 37/0244
20130101; B01J 23/10 20130101; B01D 2255/20761 20130101; B01J 23/08
20130101; B01J 35/0006 20130101; B01D 2257/30 20130101; B01J 23/72
20130101; B01D 2255/50 20130101; B01D 2255/908 20130101; B01D
2255/20707 20130101; B01J 23/75 20130101; B01D 53/945 20130101;
B01J 35/04 20130101; B01D 2255/2092 20130101; Y02C 20/10 20130101;
B01D 2255/405 20130101; B01J 35/002 20130101; B01D 2255/20753
20130101; B01J 2523/00 20130101; B01J 2523/3706 20130101; B01J
2523/3712 20130101; B01J 2523/48 20130101; B01J 2523/00 20130101;
B01J 2523/17 20130101; B01J 2523/3706 20130101; B01J 2523/3712
20130101; B01J 2523/72 20130101; B01J 2523/00 20130101; B01J
2523/3712 20130101; B01J 2523/3718 20130101; B01J 2523/3725
20130101; B01J 2523/48 20130101 |
Class at
Publication: |
423/210 ;
502/355; 502/341; 502/331; 502/100; 502/350; 502/340; 502/304;
502/226; 502/349; 502/352; 502/232; 502/1; 502/319; 502/321;
502/320; 502/322; 502/60; 502/324; 502/332; 502/337; 502/338;
502/335; 502/336; 502/346; 502/353; 502/348; 502/354 |
International
Class: |
B01D 53/86 20060101
B01D053/86; B01J 23/10 20060101 B01J023/10; B01J 23/16 20060101
B01J023/16; B01J 23/20 20060101 B01J023/20; B01J 23/26 20060101
B01J023/26; B01J 23/28 20060101 B01J023/28; B01J 23/30 20060101
B01J023/30; B01J 23/34 20060101 B01J023/34; B01J 23/50 20060101
B01J023/50; B01J 23/755 20060101 B01J023/755; B01J 23/75 20060101
B01J023/75; B01J 23/745 20060101 B01J023/745; B01J 21/08 20060101
B01J021/08; B01J 21/10 20060101 B01J021/10; B01J 21/12 20060101
B01J021/12; B01J 27/12 20060101 B01J027/12 |
Claims
1. A catalyst system, comprising: a substrate; and a washcoat,
wherein the washcoat comprises at least one oxide solid, wherein
the oxide solid is selected from the group consisting of a carrier
material oxide, a catalyst, and a mixture thereof, wherein the
catalyst system is substantially free of platinum group metals.
2. The catalyst system of claim 1, wherein the carrier material
oxide comprises one or more selected from the group consisting of
an oxygen storage material, aluminum oxide, doped aluminum oxide,
spinel, delafossite, lyonsite, garnet, perovskite, pyrochlore,
doped ceria, fluorite, zirconium oxide, doped zirconia, titanium,
tin oxide, silicon dioxide, and mixtures thereof.
3. The catalyst system of claim 1, wherein the catalyst comprises
one or more selected from the group consisting of a ZPGM transition
metal catalyst, a mixed metal oxide catalyst, a zeolite catalyst,
and mixtures thereof.
4. The catalyst system of claim 2, wherein the catalyst comprises
one or more selected from the group consisting of a ZPGM transition
metal catalyst, a mixed metal oxide catalyst, a zeolite catalyst,
and mixtures thereof.
5. The catalyst system of claim 2, wherein the oxygen storage
material comprises one or more selected from the group consisting
of cerium, zirconium, lanthanum, yttirum, lanthanides, actinides,
and mixtures thereof.
6. The catalyst system of claim 5, wherein the oxygen storage
material comprises one or more selected from the group consisting
of (a) a mixture of ceria and zirconia; (b) a mixture of ceria,
zirconia, and lanthanum; and (c) a mixture of ceria, zirconia,
neodymium, and praseodymium.
7. The catalyst system of claim 1, further comprising an overcoat
comprising at least one oxide solid, wherein the overcoat oxide
solid comprises one or more selected from the group consisting of a
carrier material oxide, a catalyst, and mixtures thereof.
8. The catalyst system of claim 7, wherein the carrier material
oxide comprises one or more selected from the group consisting of
an oxygen storage material, aluminum oxide, doped aluminum oxide,
spinel, delafossite, lyonsite, garnet, perovskite, pyrochlore,
doped ceria, fluorite, zirconium oxide, doped zirconia, titanium,
tin oxide, silicon dioxide, and mixtures thereof.
9. The catalyst system of claim 7, wherein the catalyst comprises
one or more selected from the group consisting of a ZPGM transition
metal catalyst, a mixed metal oxide catalyst, a zeolite catalyst,
and mixtures thereof.
10. The catalyst system of claim 8, wherein the catalyst comprises
one or more selected from the group consisting of a ZPGM transition
metal catalyst, a mixed metal oxide catalyst, a zeolite catalyst,
and mixtures thereof.
11. The catalyst system of claim 8, wherein the oxygen storage
material comprises one or more selected from the group consisting
of cerium, zirconium, lanthanum, yttrium, lanthanides, actinides,
and mixtures thereof.
12. The catalyst system of claim 1, wherein the catalyst system is
completely free of platinum group metals.
13. A catalyst system, comprising: a substrate; a washcoat, wherein
the washcoat comprises one or more selected from the group
consisting of a carrier material oxide, ceramic, and mixtures
thereof; and an overcoat, wherein the overcoat comprises a
catalyst, wherein the catalyst comprises one or more selected from
the group consisting of a ZPGM transition metal catalyst, a mixed
metal oxide catalyst, a zeolite catalyst, and a mixture thereof,
and wherein the catalyst system is substantially free of platinum
group metals.
14. The catalyst system of claim 13, further comprising one or more
selected from the group consisting of a perovskite, a spinel, an
oxygen storage material, alumina, and mixtures thereof.
15. The catalyst system of claim 14, further comprising one or more
selected from the group consisting of a spinel, an oxygen storage
material, alumina, and mixtures thereof.
16. The catalyst system of claim 15, further comprising one or more
selected from the group consisting of a spinel, an oxygen storage
material, alumina, and mixtures thereof.
17. The catalyst system of claim 15 or 16, further comprising one
or more selected from the group consisting of (a) a spinel and at
least one oxygen storage material; and (b) alumina and at least one
oxygen storage material.
18. The catalyst system of claim 1 or 13 wherein the catalyst
comprises at least one transition metal and at least one carrier
material oxide, wherein the transition metal comprises one or more
selected from the group consisting of chromium, manganese, iron,
cobalt, nickel, copper, niobium, molybdenum, silver, and
tungsten.
19. The catalyst system of claim 18, wherein the carrier material
oxide comprises one or more selected from the group consisting of
an oxygen storage material, aluminum oxide, doped aluminum oxide,
spinel, delafossite, lyonsite, garnet, perovskite, pyrochlore,
doped ceria, fluorite, zirconium oxide, doped zirconia, titanium,
tin oxide, silicon dioxide, and mixtures thereof.
20. The catalyst system of claim 19, wherein the oxygen storage
material comprises one or more selected from the group consisting
of cerium, zirconium, lanthanum, yttrium, lanthanides, actinides,
and mixtures thereof.
21. The catalyst system of claim 1 or 13, wherein the catalyst
comprises copper and at least one carrier material oxide.
22. The catalyst system of claim 21, wherein the catalyst is about
5% to about 50% by weight.
23. A catalyst system, comprising: a substrate, wherein the
substrate comprises cordierite; a washcoat, wherein the washcoat
comprises copper, a spinel, and at least one oxygen storage
material, wherein the spinel comprises magnesium aluminum oxide,
wherein the oxygen storage material comprises one or more selected
from the group consisting of cerium, zirconium, and lanthanum; and
an overcoat, wherein the overcoat comprises copper, a spinel, and
at least one oxygen storage material, wherein the spinel comprises
magnesium aluminum oxide, wherein the oxygen storage material
comprises one or more selected from the group consisting of cerium,
zirconium, neodymium, and praseodymium, wherein the catalyst system
is substantially free of platinum group metals.
24. The catalyst system of claim 23, wherein the aluminum oxide and
oxygen storage material of the overcoat is present in a weight
ratio of about 75 to about 25.
25. The catalyst system of claim 23, wherein the copper in the
overcoat is about 5% to about 50% by weight.
26. The catalyst system of claim 25, wherein the copper in the
overcoat is about 10% to about 16% by weight.
27. The catalyst system of claim 23, wherein the catalyst system is
completely free of platinum group metals.
28. A catalyst system, comprising: a substrate, wherein the
substrate comprises cordierite; a washcoat, wherein the washcoat
comprises lanthanum aluminum oxide and at least one oxygen storage
material; and an overcoat, wherein the overcoat comprises copper
oxide, lanthanum aluminum oxide, and at least one oxygen storage
material, wherein the catalyst system is substantially free of
platinum group metals.
29. The catalyst system of claim 28, wherein the oxygen storage
material comprises one or more selected from the group consisting
of cerium, zirconium, lanthanum, yttrium, lanthanides, actinides,
and mixtures thereof.
30. The catalyst system of claim 28, wherein the oxygen storage
material comprises one or more selected from the group consisting
of cerium, zirconium, neodymium, praseodeymium, and mixtures
thereof.
31. The catalyst system of claim 28, wherein the lanthanum aluminum
oxide and oxygen storage material of the overcoat is present in a
weight ratio of about 75 to about 25.
32. The catalyst system of claim 28, wherein the copper is present
in about 5% to about 50% by weight.
33. The catalyst system of claim 28, wherein the aluminum oxide and
the oxygen storage material of the overcoat is present in the
overcoat in a weight ratio of about 75 to about 25.
34. The catalyst system of claim 28, wherein the catalyst system is
completely free of platinum group metals.
35. A catalyst system, comprising: a substrate; a washcoat, wherein
the washcoat comprises tin aluminum oxide, copper, cerium,
zirconium, lanthanum, and at least one oxygen storage material,
wherein the oxygen storage material comprises a mixture of cerium,
zirconium, neodymium, and praseodymium; and an overcoat, wherein
the overcoat comprises aluminum, copper, and at least one oxygen
storage material, wherein the catalyst system is substantially free
of platinum group metals.
36. The catalyst system of claim 35, wherein the oxygen storage
material of the overcoat comprises one or more selected from the
group consisting of cerium, zirconium, lanthanum, yttrium,
lanthanides, actinides, and mixtures thereof.
37. The catalyst system of claim 35, wherein the aluminum oxide and
oxygen storage material are present in the washcoat in a weight
ratio of 25:75 to about 75:25.
38. The catalyst system of claim 35, wherein the aluminum oxide and
oxygen storage material are present in the washcoat in a weight
ratio of about 60 to about 40.
39. The catalyst system of claim 35, wherein the aluminum and at
least one oxygen storage material are present in the overcoat in a
weight ratio of about 60 to about 40.
40. The catalyst system of claim 35, wherein the copper present in
the overcoat is about 5% to about 20% by weight.
41. The catalyst system of claim 35, wherein the catalyst system is
completely free of platinum group metals.
42. A catalyst system, comprising: a substrate; and a washcoat,
wherein the washcoat comprises copper, tin aluminum oxide, and at
least one oxygen storage material, wherein the catalyst system is
substantially free of platinum group metals.
43. The catalyst system of claim 42, wherein the oxygen storage
material comprises one or more selected from the group consisting
of cerium, zirconium, lanthanum, neodymium, and praseodymium, and
mixtures thereof.
44. The catalyst system of claim 43, wherein the oxygen storage
material comprises a mixture of cerium, zirconium, and
lanthanum.
45. The catalyst system of claim 44, wherein the cerium, zirconium,
and lanthanum is present in the washcoat in a weight ratio of about
60 to about 30 to about 10.
46. The catalyst system of claim 42, wherein the washcoat further
comprises at least one transition metal.
47. The catalyst system of claim 42, wherein the copper present in
the washcoat is about 5% to about 30% by weight.
48. The catalyst system of claim 42, wherein the catalyst system is
completely free of platinum group metals.
49. A catalyst system, comprising: a substrate; and a washcoat,
wherein the washcoat comprises aluminum oxide, copper, and at least
one oxygen storage material, wherein the oxygen storage material
comprises a mixture of cerium, zirconium, and lanthanum, wherein
the catalyst system is substantially free of platinum group
metals.
50. The catalyst system of claim 49, wherein the aluminum oxide and
the oxygen storage material are present in the washcoat in a weight
ratio of about 60 to about 40.
51. The catalyst system of claim 49, wherein the copper present in
the washcoat is about 5% to about 20% by weight.
52. The catalyst system of claim 49, wherein the washcoat further
comprises one or more selected from the group consisting of a
transition metal, ceria, and a mixture thereof.
53. The catalyst system of claim 49, wherein the catalyst system is
completely free of platinum group metals.
54. A catalyst system, comprising: a substrate; and a washcoat,
wherein the washcoat comprises at least one carrier material oxide
and a perovskite, wherein the perovskite comprises
Ce.sub.0.6La.sub.0.4Mn.sub.0.6Cu.sub.0.4O.sub.3, wherein the
catalyst system is substantially free of platinum group metals.
55. The catalyst system of claim 54, wherein the carrier material
oxide comprises one or more oxygen storage material.
56. The catalyst system of claim 55, wherein the oxygen storage
material comprises one or more selected from the group consisting
of cerium, zirconium, lanthanum, neodymium, praseodymium, and
mixtures thereof.
57. The catalyst system of claim 1 or 13, wherein the catalyst
comprises at least one transition metal, at least one alkaline
earth metal, cerium, and a carrier material oxide, wherein the
transition metal comprises one or more selected from the group
consisting of chromium, manganese, iron, cobalt, nickel, copper,
niobium, molybdenum, tungsten, silver, and mixtures thereof, and
wherein the alkaline earth metal comprises one or more selected
from the group consisting of magnesium, calcium, barium, strontium,
and mixtures thereof.
58. The catalyst system of claim 57, wherein the alkaline earth
metal and cerium are present in about 5% to about 50% by
weight.
59. The catalyst system of claim 1 or 13, wherein the catalyst
comprises at least one transition metal, at least one alkaline
earth metal, and a carrier material oxide, wherein the transition
metal comprises one or more selected from the group consisting of
chromium, manganese, iron, cobalt, nickel, copper, niobium,
molybdenum, tungsten, silver, and mixtures thereof, and wherein the
alkaline earth metal comprises one or more selected from the group
consisting of magnesium, calcium, barium, strontium, and mixtures
thereof.
60. The catalyst system of claim 59, wherein the transition metal
comprises one or more selected from the group consisting of copper,
nickel, cobalt, and mixtures thereof.
61. The catalyst system of claim 59, wherein the alkaline earth
metal comprises one or more selected from the group consisting of
barium, strontium, and mixtures thereof.
62. The catalyst system of claim 59, wherein the alkaline earth
metal and the transition metal are present in a molar ratio of
about 1:10 to 1:1.
63. The catalyst system of claim 59, wherein the alkaline earth
metal and the transition metal is about 2% to about 50% weight.
64. The catalyst system of claim 1 or 13, wherein the catalyst
comprises at least one transition metal and a perovskite having the
formula ABO.sub.3, wherein A comprises one or more selected from
the group consisting of lanthanum, cerium, magnesium, calcium,
barium, strontium, lanthanides, actinides, and mixtures thereof,
wherein B comprises one or more selected from the group consisting
of iron, manganese, copper, nickel, cobalt, cerium, and mixtures
thereof.
65. The catalyst system of claim 64, wherein the transition metal
comprises one or more selected from the group consisting of copper,
nickel, cobalt, manganese, iron, chromium, niobium, molybdenum,
tungsten, silver, and mixtures thereof.
66. The catalyst system of claim 65, wherein the transition metal
comprises one or more selected from the group consisting of copper,
nickel, cobalt, and mixtures thereof.
67. The catalyst system of claim 64, wherein the transition metal
is present in about 2% to about 30% by weight.
68. The catalyst system of claim 1 or 13, wherein the catalyst
comprises a perovskite, at least one transition metal, and at least
one carrier material oxide.
69. The catalyst system of claim 68, wherein the transition metal
comprises one or more selected from the group consisting of
chromium, manganese, iron, cobalt, nickel, copper, niobium,
molybdenum, tungsten, and mixtures thereof.
70. The catalyst system of claim 68, wherein the carrier material
oxide comprises one or more selected from the group consisting of
an oxygen storage material, aluminum oxide, doped aluminum oxide,
spinel, delafossite, lyonsite, garnet, perovskite, pyrochlore,
doped ceria, fluorite, zirconium oxide, doped zirconia, titanium,
tin oxide, silicon dioxide, and mixtures thereof.
71. The catalyst system of claim 70, wherein the oxygen storage
material comprises one or more selected from the group consisting
of cerium, zirconium, lanthanum, yttrium, lanthanides, actinides,
and mixtures thereof.
72. The catalyst system of claim 68, wherein the perovskite and
transition metal are present in about 5% to about 50% by
weight.
73. The catalyst system of claim 1 or 13, wherein the catalyst
comprises at least one transition metal and a spinel having the
formula AB.sub.2O.sub.4, wherein A comprises one or more selected
from the group consisting of aluminum, magnesium, manganese,
gallium, nickel, copper, cobalt, iron, chromium, niobium, titanium,
tin, and mixtures thereof; and wherein B comprises one or more
selected from the group consisting of aluminum, magnesium,
manganese, gallium, nickel, copper, cobalt, iron, chromium,
niobium, titanium, tin, and mixtures thereof, wherein A and B are
different.
74. The catalyst system of claim 73, wherein the transition metal
comprises one or more selected from the group consisting of
manganese, iron, cobalt, nickel, copper, niobium, molybdenum,
tungsten, silver, and mixtures thereof.
75. The catalyst system of claim 73, wherein the spinel has the
formula MgAl.sub.2O.sub.4.
76. The catalyst system of claim 73, wherein the transition metal
is present in about 2% to about 30% by weight.
77. The catalyst system of claim 73, further comprising a carrier
material oxide.
78. The catalyst system of claim 77, wherein the carrier material
oxide comprises one or more selected from the group consisting of
an oxygen storage material, aluminum oxide, doped aluminum oxide,
spinel, delafossite, lyonsite, garnet, perovskite, pyrochlore,
doped ceria, fluorite, zirconium oxide, doped zirconia, titanium,
tin oxide, silicon dioxide, and mixtures thereof.
79. The catalyst system of claim 78, wherein the oxygen storage
material comprises one or more selected from the group consisting
of cerium, zirconium, lanthanum, yttrium, lanthanides, actinides,
and mixtures thereof.
80. The catalyst system of claim 73, wherein the spinel and
transition metal are present in about 5% to about 50% by
weight.
81. The catalyst system of claim 1 or 13, wherein the catalyst
comprises a mixed metal oxide and at least one transition metal,
wherein the mixed metal oxide comprises one or more selected from
the group consisting of alkali metals, alkaline earth metals,
lanthanides, actinides, and mixtures thereof.
82. The catalyst system of claim 81, wherein the mixed metal oxide
comprises one or more selected from the group consisting of a
spinel, a perovskite, a delafossite, a lyonsite, a garnet, and a
pyrochlore.
83. The catalyst system of claims 1 or 13, wherein the catalyst
comprises a perovskite having the formula ABO.sub.3, wherein A
comprises one or more selected from the group consisting lanthanum,
lanthanides, actinides, cerium, magnesium, calcium, barium,
strontium, and mixtures thereof, and wherein B comprises at least
one transition metal.
84. The catalyst system of claim 83, wherein the transition metal
comprises one or more selected from the group consisting of iron,
manganese, copper, nickel, cobalt, cerium, and mixtures
thereof.
85. The catalyst system of claim 1 or 13, wherein the catalyst
comprises a perovskite having the formula A.sub.a-xB.sub.xMO.sub.b,
wherein A comprises one or more selected from the group consisting
lanthanum, lanthanides, actinides, cerium, magnesium, calcium,
barium, strontium, and mixtures thereof, wherein B comprises one or
more transition metal, wherein a is selected from the group
consisting of 1 and 2, wherein b is selected from the group consist
of 3, when a is 1, and 4 when a is 2, and wherein z is a number
defined by 0.1.ltoreq.x<0.7.
86. The catalyst system of claim 85, wherein the transition metal
comprises one or more selected from the group consisting of iron,
manganese, copper, nickel, cobalt, cerium, and mixtures
thereof.
87. The catalyst system of claim 1 or 13, wherein the catalyst
comprises a perovskite having the formula
AMn.sub.1-xCu.sub.xO.sub.3, wherein A comprises one or more
selected from the group consisting of lanthanum, cerium, barium,
strontium, lanthanides, actinides, and mixtures thereof, and
wherein x is 0 to 1.
88. The catalyst system of claim 1 or 13, wherein the catalyst
comprises a perovskite having the formula
ACe.sub.1-xCu.sub.xO.sub.3, wherein A comprises one or more
selected from the group consisting of barium, strontium, calcium,
and mixtures thereof, and wherein x is 0 to 1.
89. The catalyst system of claim 1 or 13, wherein the catalyst
comprises a spinel having the formula AB.sub.2O.sub.4, wherein A
comprises one or more selected from the group consisting of
aluminum, magnesium, manganese, gallium, nickel, copper, cobalt,
iron, chromium, titanium, tin, and mixtures thereof; and wherein B
comprises one or more selected from the group consisting of
aluminum, magnesium, manganese, gallium, nickel, copper, cobalt,
iron, chromium, titanium, tin, and mixtures thereof, wherein A and
B are different.
90. The catalyst system of claim 89, further comprising a carrier
material oxide.
91. The catalyst system of claim 90, wherein the carrier material
oxide comprises one or more selected from the group consisting of
an oxygen storage material, aluminum oxide, doped aluminum oxide,
spinel, delafossite, lyonsite, garnet, perovskite, pyrochlore,
doped ceria, fluorite, zirconium oxide, doped zirconia, titanium,
tin oxide, silicon dioxide, and mixtures thereof.
92. The catalyst system of claim 91, wherein the oxygen storage
material comprises one or more selected from the group consisting
of cerium, zirconium, lanthanum, yttrium, lanthanides, actinides,
and mixtures thereof.
93. The catalyst system of claim 89, wherein the spinel is present
in the catalyst in about 5% to about 50% by weight.
94. The catalyst system of claim 1 or 13, wherein the catalyst
comprises at least one zeolite and at least one transition
metal.
95. The catalyst system of claim 94, wherein the zeolite comprises
one or more selected from the group consisting of ZSM5, heulandite,
chabazite, and mixtures thereof.
96. The catalyst system of claim 94, wherein the transition metal
comprises one or more selected from the group consisting of
chromium, gallium, manganese, iron, cobalt, nickel, copper,
niobium, molybdenum, tungsten, silver, and mixtures thereof.
97. The catalyst system of claim 96, wherein the transition metal
comprises one or more selected from the group consisting of copper,
nickel, gallium, cobalt, and mixtures thereof.
98. The catalyst system of claim 94, wherein the transition metal
is present in about 3% to about 25% by weight.
99. A method of making a catalyst system by impregnation,
comprising: depositing a washcoat on a substrate, wherein the
washcoat comprises at least one oxide solid, wherein the oxide
solid comprises one or more selected from the group consisting of a
carrier material oxide, a catalyst, and a mixture thereof; treating
the washcoat and the substrate to convert metal salts into metal
oxides; wherein the catalyst system is substantially free of
platinum group metals.
100. The method of claim 99, wherein the treating is at a
temperature of about 550.degree. C. for about 4 hours.
101. The method of claim 99, wherein the carrier material oxide
comprises one or more selected from the group consisting of an
oxygen storage material, aluminum oxide, doped aluminum oxide,
spinel, delafossite, lyonsite, garnet, perovskite, pyrochlore,
doped ceria, fluorite, zirconium oxide, doped zirconia, titanium,
tin oxide, silicon dioxide, and mixtures thereof.
102. The method of claim 101, wherein the oxygen storage material
comprises one or more selected from the group consisting of cerium,
zirconium, lanthanum, yttrium, lanthanides, actinides, and mixtures
thereof.
103. The method of claim 99, wherein the washcoat comprises copper
and at least one oxygen storage material.
104. The method of claim 103, wherein the oxygen storage material
comprises one or more selected from the group consisting of cerium,
zirconium, lanthanum, yttrium, lanthanides, actinides, and mixtures
thereof.
105. The method of claim 99, further comprising after treating:
depositing an overcoat on the washcoat, wherein the overcoat
comprises at least one oxide solid, wherein the oxide solid
comprises one or more selected from the group consisting of a
carrier material oxide, a catalyst, and mixtures thereof, treating
the overcoat and the washcoat at a temperature of about 550.degree.
C. for about 4 hours.
106. The method of claim 105, wherein the carrier material oxide
comprises one or more selected from the group consisting of an
oxygen storage material, aluminum oxide, doped aluminum oxide,
spinel, delafossite, lyonsite, garnet, perovskite, pyrochlore,
doped ceria, fluorite, zirconium oxide, doped zirconia, titanium,
tin oxide, silicon dioxide, and mixtures thereof.
107. The method of claim 106, wherein the oxygen storage material
comprises one or more selected from the group consisting of cerium,
zirconium, lanthanum, yttrium, lanthanides, actinides, and mixtures
thereof.
108. The method of claim 104, wherein the catalyst comprises one or
more selected from the group consisting of a ZPGM transition metal
catalyst, a mixed metal oxide catalyst, a zeolite catalyst, and
mixtures thereof.
109. The method of claim 104, wherein the washcoat further
comprises tin.
110. The method of claim 99, wherein the catalyst system is
completely free of platinum group metals.
111. A method of making a catalyst system by precipitation,
comprising: precipitating a transition metal salt on a washcoat,
wherein, the transition metal salt comprises at least one
transition metal and at least one carrier material oxide, wherein
the washcoat comprises at least one carrier material oxide;
treating the precipitated transition metal salt and the washcoat;
depositing the precipitated transition metal salt and the washcoat
on a substrate; and treating the precipitated transition metal salt
and the washcoat on the substrate; wherein the catalyst system is
substantially free of platinum group metals.
112. The method of claim 111, wherein the treating is at a
temperature of about 550.degree. C. for about 4 hours.
113. The method of claim 111, further comprising after treating the
precipitated transition metal salt and the washcoat on the
substrate: depositing an overcoat on the treated precipitated
transition metal salt and the washcoat; and treating the overcoat,
the treated precipitated transition metal salt, and the
washcoat.
114. The method of claim 111, wherein the treating is at a
temperature of about 550.degree. C. for about 4 hours.
115. The method of claim 111, wherein the overcoat comprises
aluminum, copper, and at least one carrier material oxide.
116. The method of claim 111 or 113, wherein the carrier material
oxide comprises one or more selected from the group consisting of
an oxygen storage material, aluminum oxide, doped aluminum oxide,
spinel, delafossite, lyonsite, garnet, perovskite, pyrochlore,
doped ceria, fluorite, zirconium oxide, doped zirconia, titanium,
tin oxide, silicon dioxide, and mixtures thereof.
117. The method of claim 116, wherein the oxygen storage material
comprises one or more selected from the group consisting of cerium,
zirconium, lanthanum, yttrium, lanthanides, actinides, and mixtures
thereof.
118. The method of claim 111, wherein the transition metal
comprises one or more selected from the group consisting of
chromium, manganese, iron, cobalt, nickel, copper, niobium,
molybdenum, tungsten, silver, and mixtures thereof.
119. The method of claim 118, wherein the transition metal
comprises copper.
120. The method of claim 111, wherein the washcoat further
comprises tin.
121. The method of claim 111, wherein the catalyst system is
completely free of platinum group metals.
122. A method of making a catalyst system by co-milling,
comprising: milling together a catalyst and at least one carrier
material oxide, wherein the catalyst comprises one or more selected
from the group consisting of a ZPGM transition metal catalyst, a
mixed metal oxide catalyst, a zeolite catalyst, and mixtures
thereof; depositing the milled catalyst in the form of a washcoat
on to a substrate; and treating the substrate and the washcoat;
wherein the catalyst system is substantially free of platinum group
metals.
123. The method of claim 122, wherein the treating is at a
temperature of about 550.degree. C. for about 4 hours.
124. The method of claim 122, further comprising: depositing an
overcoat on the washcoat; and treating the overcoat and the
washcoat.
125. The method of claim 124, wherein the treating is at a
temperature of about 550.degree. C. for about 4 hours.
126. The method of claim 124, wherein the overcoat comprises at
least one oxide solid, wherein the oxide solid comprises one or
more selected from the group consisting of a carrier material
oxide, a catalyst, and mixtures thereof.
127. The method of claim 126, wherein the overcoat comprises
aluminum, copper, and at least one carrier material oxide.
128. The method of claim 122, wherein the catalyst system is
completely free of platinum group metals.
129. A method of reducing pollutants emitted in exhaust,
comprising: flowing exhaust substantially through a catalyst
system, wherein the catalyst system comprises, a substrate; and a
washcoat, wherein the washcoat comprises at least one oxide solid,
wherein the oxide solid comprises one or more selected from the
group consisting of a carrier material oxide, a catalyst, and a
mixture thereof; wherein the catalyst system is substantially free
of platinum group metals; wherein the exhaust comprises pollutants;
and reducing the pollutants in the exhaust.
130. The method of claim 129, wherein the washcoat comprises
copper.
131. The method of claim 130, wherein the washcoat comprises about
8% copper by weight.
132. The method of claim 129, wherein the catalyst further
comprises an overcoat, wherein the overcoat comprises copper and at
least one carrier material oxide.
133. The method of claim 129, wherein the aluminum oxide and the
carrier material oxide are present in a weight ratio of about
60:40.
134. The method of claim 129, wherein the washcoat further
comprises tin.
135. The method of claim 129, wherein the pollutants comprise
nitrogen oxide, hydrocarbon, carbon monoxide, and sulfur.
136. The method of claim 129, wherein the catalyst comprises one or
more selected from the group consisting of a ZPGM transition metal
catalyst, a mixed metal oxide catalyst, a zeolite catalyst, and a
mixture thereof.
137. The method of claim 129, wherein the catalyst system further
comprises: an overcoat, wherein the overcoat comprises an catalyst,
wherein the catalyst comprises one or more selected from the group
consisting of a ZPGM transition metal catalyst, a mixed metal oxide
catalyst, a zeolite catalyst, and a mixture thereof.
138. The method of claim 129, wherein the catalyst system is
completely free of platinum group metals.
139. A catalyst system, comprising: a first catalyst system,
comprising a substrate; and a washcoat, wherein the washcoat
comprises at least one oxide solid, wherein the oxide solid
comprises one or more selected from the group consisting of a
carrier material oxide, a catalyst, and a mixture thereof; wherein
the first catalyst system is substantially free of platinum group
metals; and a second catalyst system, wherein the second catalyst
system comprises at least one platinum group metal; wherein the
first catalyst and the second catalyst are in series in any order,
and wherein a gas stream is capable of passing through the first
catalyst system and the second catalyst system sequentially.
140. The catalyst system of claim 139, wherein the platinum group
metal comprises one or more selected from the group consisting of
palladium, platinum, ruthenium, iridium, osmium, and rhodium.
141. The catalyst system of claim 139, wherein the gas stream is
capable of passing through the first catalyst system and the second
catalyst system in any sequence.
142. The catalyst system of claim 139, wherein the second catalyst
system comprises one or more platinum group metal and one or more
carrier material oxide.
143. The catalyst system of claim 139, wherein the second catalyst
system comprises one or more platinum group metal and one or more
carrier material oxide.
144. The catalyst system of claim 139, wherein the oxygen storage
material of the first catalyst comprises one or more selected from
the group consisting of cerium, zirconium, lanthanum, neodymium,
praseodymium, and mixtures thereof.
145. The catalyst system of claim 139, wherein the first catalyst
system and the second catalyst system are in series such the gas
stream is capable of passing through the second catalyst followed
by the first catalyst.
146. The catalyst system of claim 139, wherein the first catalyst
system further comprises: an overcoat, wherein the overcoat
comprises a catalyst, wherein the catalyst comprises one or more
selected from the group consisting of a ZPGM transition metal
catalyst, a mixed metal oxide catalyst, a zeolite catalyst, and a
mixture thereof.
Description
TECHNICAL FIELD OF THE INVENTION
[0001] The present invention relates to catalysts which are free of
any platinum group metals for reducing emissions of nitrous oxide,
carbon monoxide, hydrocarbons, and sulfur in exhaust streams.
BACKGROUND OF THE INVENTION
[0002] Catalysts in catalytic converters have been used to decrease
the pollution caused by exhaust from various sources, such as
automobiles, utility plants, processing and manufacturing plants,
airplanes, trains, all terrain vehicles, boats, mining equipment,
and other engine-equipped machines. A common catalyst used in this
way is the three-way catalyst ("TWC"). The TWC works by converting
carbon monoxide, hydrocarbons, and nitrogen oxides into less
harmful compounds or pollutants. Specifically, a TWC works by
simultaneously reducing the nitrogen oxides to nitrogen and oxygen,
oxidizing carbon monoxide to less harmful carbon dioxide, and
oxidizing unburnt hydrocarbons to carbon dioxide and water. The
prior art TWC is made using at least some platinum group metals.
Platinum group metals are defined in this specification to mean
platinum, palladium, ruthenium, iridium, osmium, and rhodium in
this application unless otherwise stated.
[0003] With the ever stricter standards for acceptable emissions,
the demand on platinum group metals continues to increase due to
their efficiency in removing pollutants from exhaust. However, this
demand along with other demands for platinum group metals places a
strain on the supply of platinum group metals, which in turn drives
up the cost of platinum group metals and therefore catalysts and
catalytic converters. Therefore, there is a need for a catalyst
that does not require platinum group metals, and has a similar or
better efficiency as the prior art catalysts.
SUMMARY OF THE INVENTION
[0004] The present invention pertains to a catalyst system
comprising a substrate and a washcoat, wherein the catalyst system
is substantially free of platinum group metals. The washcoat
comprises at least one oxide solid, wherein the oxide solid is
selected from the group consisting of a carrier material oxide, a
catalyst, and a mixture thereof. The carrier material oxide
comprises one or more selected from the group consisting of an
oxygen storage material, aluminum oxide, doped aluminum oxide,
spinel, delafossite, lyonsite, garnet, perovskite, pyrochlore,
doped ceria, fluorite, zirconium oxide, doped zirconia, titanium,
tin oxide, silicon dioxide, and mixtures thereof. The catalyst
comprises one or more selected from the group consisting of a ZPGM
transition metal catalyst, a mixed metal oxide catalyst, a zeolite
catalyst, and mixtures thereof. The oxygen storage material
comprises one or more selected from the group consisting of cerium,
zirconium, lanthanum, yttirum, lanthanides, actinides, and mixtures
thereof. The catalyst system may optionally comprise an overcoat
comprising at least one oxide solid, wherein the overcoat oxide
solid comprises one or more selected from the group consisting of a
carrier material oxide, a catalyst, and mixtures thereof.
[0005] The present invention also pertains to a catalyst system
comprising a substrate, a washcoat, and an overcoat, wherein the
catalyst system is substantially free of platinum group metals. The
washcoat comprises one or more selected from the group consisting
of a carrier material oxide, ceramic, and mixtures thereof. The
overcoat comprises a catalyst. The catalyst of the overcoat
comprises one or more selected from the group consisting of a ZPGM
transition metal catalyst, a mixed metal oxide catalyst, a zeolite
catalyst, and mixtures thereof. The catalyst system may further
comprise one or more selected from the group consisting of a
perovskite, a spinel, a lyonsite, an oxygen storage material,
alumina, and mixtures thereof.
[0006] A ZPGM transition metal catalyst comprises one or more
transition metals. A mixed metal oxide catalyst comprises a mixed
metal oxide and at least one transition metal, wherein the mixed
metal oxide comprises one or more selected from the group
consisting of alkali metals, alkaline earth metals, lanthanides,
actinides, and mixtures thereof. A zeolite catalyst comprises at
least one zeolite and at least one transition metal. The zeolite
comprises one or more selected from the group consisting of ZSM5,
heulandite, chabazite, and mixtures thereof. The transition metal
comprises one or more selected from the group consisting of
chromium, gallium, manganese, iron, cobalt, nickel, copper,
niobium, molybdenum, tungsten, silver, and mixtures thereof
[0007] The present invention also pertains to a method of making a
catalyst system by impregnation, comprising depositing a washcoat
on a substrate and treating the washcoat and the substrate to
convert metal salts into metal oxides, wherein the catalyst system
is substantially free of platinum group metals. The washcoat
comprises at least one oxide solid, wherein the oxide solid
comprises one or more selected from the group consisting of a
carrier material oxide, a catalyst, and mixtures thereof. The
method may further comprise after treating, depositing an overcoat
on the washcoat and treating the overcoat and washcoat. The
overcoat comprises at least one oxide solid, wherein the oxide
solid comprises one or more selected from the group consisting of a
carrier material oxide, a catalyst, and mixtures thereof.
[0008] The present invention also pertains to a method of making a
catalyst system by precipitation, comprising precipitating a
transition metal salt on a washcoat, treating the precipitated
transition metal salt and the washcoat, depositing the precipitated
transition metal salt and the washcoat on a substrate, and treating
the precipitated transition metal salt and the washcoat on the
substrate, wherein the catalyst system is substantially free of
platinum group metals. The transition metal salt comprises at least
one transition metal and at least one carrier material oxide. The
method may further comprise after treating the precipitated
transition metal salt and the washcoat on the substrate, depositing
an overcoat on the treated precipitated transition metal salt and
the washcoat, and treating the overcoat, the treated precipitated
transition metal salt and the washcoat.
[0009] The present invention also pertains to a method of making a
catalyst system by co-milling, comprising milling together a
catalyst and at least one carrier material oxide, depositing the
milled catalyst in the form of a washcoat on to a substrate; and
treating the substrate and the washcoat, wherein the catalyst
system is substantially free of platinum group metals. The method
may further comprise depositing an overcoat on the washcoat and
treating the overcoat and the washcoat. The overcoat comprises at
least one oxide solid, wherein the oxide solid comprises one or
more selected from the group consisting of a carrier material
oxide, a catalyst, and mixtures thereof.
[0010] The present invention also pertains to a method of reducing
pollutants including, but not limited to nitrogen oxide, carbon
monoxide, hydrocarbons, and sulfur emitted in exhaust comprising
flowing exhaust substantially through a catalyst system as
described herein and reducing the pollutants in the exhaust.
[0011] The present invention also pertains to a catalyst system
comprising a first catalyst system and a second catalyst system.
The first catalyst system comprises a substrate and a washcoat,
wherein the washcoat comprises at least one oxide solid and wherein
the first catalyst system is substantially free of platinum group
metals. The second catalyst system comprises at least one platinum
group metal. The first and second catalyst systems are in series in
any order, wherein at least a substantial portion of a gas stream
passes through the first catalyst and the second catalyst
sequentially. More than a first and second catalyst system may be
used in a catalyst system, e.g. a third catalyst system or
more.
BRIEF DESCRIPTION OF THE FIGURES
[0012] FIG. 1 shows a schematic of Architecture 1 for the catalyst
systems of the present invention;
[0013] FIG. 2 shows a schematic of Architecture 2 for the catalyst
systems of the present invention;
[0014] FIG. 3 shows a schematic of Architecture 3 for the catalyst
systems of the present invention;
[0015] FIG. 4 shows the pore volume results for fresh catalyst
systems ZPGM-1 through ZPGM-5;
[0016] FIG. 5 shows the pore volume results for aged catalyst
systems ZPGM-1 through ZPGM-5;
[0017] FIG. 6 shows the surface area summary for fresh and aged
catalyst systems ZPGM-1 through ZPGM-5;
[0018] FIG. 7 shows the x-ray diffraction analysis of a ZPGM-1
catalyst system (fresh and aged
Ce.sub.0.6La.sub.0.4Mn.sub.0.6Cu.sub.0.4O.sub.x powders);
[0019] FIG. 8 shows the x-ray diffraction analysis of a ZPGM-2
catalyst system (fresh and aged);
[0020] FIG. 9 shows the x-ray diffraction analysis of a ZPGM-3
catalyst system (fresh and aged);
[0021] FIG. 10 shows the x-ray diffraction analysis of a ZPGM-4
catalyst system (fresh and aged);
[0022] FIG. 11 shows the x-ray diffraction analysis of a ZPGM-5
catalyst system (fresh and aged);
[0023] FIG. 12 shows the x-ray diffraction analysis of a ZPGM-6
catalyst system (fresh and aged);
[0024] FIG. 13 shows the sweep test results for a ZPGM-1 catalyst
system (fresh and aged);
[0025] FIG. 14 shows the sweep test results for a ZPGM-2 catalyst
system (fresh and aged);
[0026] FIG. 15 shows the sweep test results for a ZPGM-3 catalyst
system (fresh and aged);
[0027] FIG. 16 shows the sweep test results for a ZPGM-4 catalyst
system (fresh and aged);
[0028] FIG. 17 shows the sweep test results for a ZPGM-5 catalyst
system (fresh and aged);
[0029] FIG. 18 shows the sweep test results for a ZPGM-6 catalyst
system (fresh and aged);
[0030] FIG. 19 shows the results of light off tests for an example
of a Type D ZPGM transition metal catalyst;
[0031] FIG. 20 shows the results of light off tests for an example
of a Type D/Type H ZPGM transition metal catalyst;
[0032] FIG. 21 shows the results of light off tests for an example
of a Type D/Type H ZPGM transition metal catalyst;
[0033] FIG. 22 shows the results of light off tests for an example
of a Type F mixed metal oxide catalyst;
[0034] FIG. 23 shows the results of light off tests for an example
of a Type F mixed metal oxide catalyst;
[0035] FIG. 24 shows the results of light off tests for an example
of a Type F mixed metal oxide catalyst;
[0036] FIG. 25 shows the results of light off tests for an example
of a Type G ZPGM transition metal catalyst;
[0037] FIG. 26 shows the results of light off tests for an example
of a Type G ZPGM transition metal catalyst;
[0038] FIG. 27 shows the results of light off tests for an example
of a Type G/Type D ZPGM transition metal catalyst;
[0039] FIG. 28 shows the results of light off tests for an example
of a Type G/Type D ZPGM transition metal catalyst;
[0040] FIG. 29 shows the results of ramp light off tests for an
example of a Type D ZPGM transition metal catalyst;
[0041] FIG. 30 shows the results of ramp light off tests for an
example of a Type I;
[0042] FIG. 31 shows light off test results for architecture 3;
[0043] FIG. 32 shows the results of a light-off test for a ZPGM-1
catalyst system (fresh and aged);
[0044] FIG. 33 shows the results of a light-off test for a ZPGM-2
catalyst system (fresh and aged);
[0045] FIG. 34 shows the results of a light-off test for a ZPGM-3
catalyst system (fresh and aged);
[0046] FIG. 35 shows the results of a light-off test for a ZPGM-4
catalyst system (fresh and aged);
[0047] FIG. 36 shows the results of a light-off test for a ZPGM-5
catalyst system (fresh and aged); and
[0048] FIG. 37 shows the results of a light-off test for a ZPGM-6
catalyst system (fresh and aged).
DEFINITIONS
[0049] The following definitions are provided to clarify the
invention.
[0050] The term "catalyst system" is defined in this specification
to mean a substrate, a washcoat, and optionally an overcoat as
illustrated by Architecture 1, Architecture 2, or Architecture 3 as
set forth in FIG. 1, 2, and 3, respectively.
[0051] The term "substrate" is defined in this specification to
mean any material known in the art for supporting a catalyst and
can be of any shape or configuration that yields a sufficient
surface area for the deposit of the washcoat and/or overcoat,
including, but not limited to a honeycomb, pellets, or beads.
[0052] The term "washcoat" is defined in this specification to mean
a coating comprising one or more oxide solids that is coupled with
a substrate.
[0053] The term "overcoat" is defined in this specification to mean
a coating comprising one or more oxide solids that is coupled with
a substrate and a washcoat.
[0054] The term "oxide solid" is defined in this specification to
mean one or more selected from the group consisting of a carrier
material oxide, a catalyst, and mixtures thereof.
[0055] The term "carrier material oxide" is defined in this
specification to mean materials used for providing a surface for at
least one catalyst and comprises one or more selected from the
group consisting of oxygen storage material, aluminum oxide, doped
aluminum oxide, spinel, delafossite, lyonsite, garnet, perovksite,
pyrochlore, doped ceria, fluorite, zirconium oxide, doped zirconia,
titanium oxide, tin oxide, silicon dioxide, zeolite, and mixtures
thereof.
[0056] The term "oxygen storage material" is defined in this
specification to mean materials that can take up oxygen from
oxygen-rich feed streams and release oxygen to oxygen-deficient
feed streams. The oxygen storage material comprises one or more
oxides selected from the group consisting of cerium, zirconium,
lanthanum, yttrium, lanthanides, actinides, and mixtures
thereof.
[0057] The term "catalyst" is defined in this specification to mean
a catalyst for decreasing the amount of nitrogen oxide,
hydrocarbon, carbon monoxide, and/or sulfur that is free of
platinum group metals, preferably completely free of platinum group
metals.
[0058] The term "ZPGM Transition Metal Catalyst" is defined in this
specification to mean a catalyst comprising one or more transition
metals.
[0059] The term "Mixed Metal Oxide Catalyst" is defined in this
specification to mean a catalyst comprising at least one transition
metal and at least one other metal.
[0060] The term "Zeolite Catalyst" is defined in this specification
to mean a catalyst comprising at least one zeolite and at least one
transition metal.
[0061] The term "transition metal" is defined in this specification
to mean the transition metals of the periodic table excluding the
platinum group metals, which are scandium, titanium, vanadium,
chromium, manganese, iron, cobalt, nickel, copper, zinc, yttrium,
zirconium, niobium, molybdenum, technetium, ruthenium, silver,
cadmium, hafnium, tantalum, tungsten, rhenium, gold, mercury,
rutherfordium, dubnium, seaborgium, bohrium, hassium, meitnerium,
ununnilium, unununium, ununbium, and gallium.
[0062] The term "copper" is defined in this specification to mean
copper, copper complexes, copper atoms, or any other copper
compounds known in the art.
[0063] The term "free" is defined in this specification to mean
substantially free or completely free.
[0064] The term "impregnation component" is defined in this
specification to mean one or more components added to a washcoat
and/or overcoat to yield a washcoat and/or overcoat comprising a
catalyst. The impregnation component comprises one or more selected
from the group consisting of a transition metal, alkali and
alkaline earth metal, cerium, lanthanum, yttrium, lanthanides,
actinides, and mixtures thereof.
[0065] The term "depositing," "deposited," or "deposit(s)" is
defined in this specification to include, without limitation,
placing, adhering, curing, coating (such as vacuum coating),
spraying, dipping, painting and any known process for coating a
film on a substrate.
[0066] The term "treating," "treated," or "treatment" is defined in
this specification to include, without limitation, precipitation,
drying, firing, heating, evaporating, calcining, or mixtures
thereof.
[0067] The term "platinum group metals" is defined in this
specification to mean platinum, palladium, ruthenium, iridium,
osmium, and rhodium.
[0068] The term "coupled with" is defined in this specification to
mean the washcoat and/or overcoat is in a relationship with the
substrate or each other, such that they may be directly in contact
with each other; or they may be associated with each other, but
there may be something in between each of them, e.g. the overcoat
may be coupled with a substrate, but a washcoat may be in between
the substrate and the overcoat.
[0069] Examples of catalyst systems are denoted by "ZPGM" and a
number, e.g. "ZPGM-1". Examples of catalysts are denoted by "Type"
and a letter, e.g. "Type A".
[0070] All percentages discussed herein are weight percent unless
otherwise indicated. All ratios discussed herein are weight ratios
unless otherwise indicated.
DETAILED DESCRIPTION
[0071] The catalyst system of the present invention is free of
platinum group metals; decreases the amount of at least one of
carbon monoxide, nitrogen oxides, hydrocarbon, and sulfur
emissions; and comprises one or more catalysts.
Substrates
[0072] The substrate of the present invention may be, without
limitation, a refractive material, a ceramic substrate, a honeycomb
structure, a metallic substrate, a ceramic foam, a metallic foam, a
reticulated foam, or suitable combinations, where the substrate has
a plurality of channels and at least the required porosity.
Porosity is substrate dependent as is known in the art.
Additionally, the number of channels may vary depending upon the
substrate used as is known in the art. The channels found in a
monolith substrate are described in more detail below. The type and
shape of a suitable substrate would be apparent to one of ordinary
skill in the art. Preferably, all of the substrates, either
metallic or ceramic, offer a three-dimensional support
structure.
[0073] In one embodiment, the substrate may be in the form of beads
or pellets. The beads or pellets may be formed from, without
limitation, alumina, silica alumina, silica, titania, mixtures
thereof, or any suitable material. In another embodiment, the
substrate may be, without limitation, a honeycomb substrate. The
honeycomb substrate may be a ceramic honeycomb substrate or a metal
honeycomb substrate. The ceramic honeycomb substrate may be formed
from, for example without limitation, sillimanite, zirconia,
petalite, spodumene (lithium aluminum silicate), magnesium
silicates, mullite, alumina, cordierite (e.g.
Mg.sub.2A.sub.14Si.sub.5O.sub.18), other alumino-silicate
materials, silicon carbide, aluminum nitride, or combinations
thereof. Other ceramic substrates would be apparent to one of
ordinary skill in the art.
[0074] If the substrate is a metal honeycomb substrate, the metal
may be, without limitation, a heat-resistant base metal alloy,
particularly an alloy in which iron is a substantial or major
component. The surface of the metal substrate may be oxidized at
elevated temperatures above about 1000.degree. C. to improve the
corrosion resistance of the alloy by forming an oxide layer on the
surface of the alloy. This oxide layer on the surface of the alloy
may also enhance the adherence of a washcoat to the surface of the
monolith substrate.
[0075] In one embodiment, the substrate may be a monolithic carrier
having a plurality of fine, parallel flow passages extending
through the monolith. The passages can be of any suitable
cross-sectional shape and/or size. The passages may be, for example
without limitation, trapezoidal, rectangular, square, sinusoidal,
hexagonal, oval, or circular, although other shapes are also
suitable. The monolith may contain from about 9 to about 1200 or
more gas inlet openings or passages per square inch of cross
section, although fewer passages may be used.
[0076] The substrate can also be any suitable filter for
particulates. Some suitable forms of substrates may include,
without limitation, woven filters, particularly woven ceramic fiber
filters, wire meshes, disk filters, ceramic honeycomb monoliths,
ceramic or metallic foams, wall flow filters, and other suitable
filters. Wall flow filters are similar to honeycomb substrates for
automobile exhaust gas catalysts. They may differ from the
honeycomb substrate that may be used to form normal automobile
exhaust gas catalysts in that the channels of the wall flow filter
may be alternately plugged at an inlet and an outlet so that the
exhaust gas is forced to flow through the porous walls of the wall
flow filter while traveling from the inlet to the outlet of the
wall flow filter.
Washcoats
[0077] According to an embodiment, at least a portion of the
catalyst of the present invention may be placed on the substrate in
the form of a washcoat. The oxide solids in the washcoat may be one
or more carrier material oxide, one or more catalyst, or a mixture
of carrier material oxide(s) and catalyst(s). Carrier material
oxides are normally stable at high temperatures (>1000.degree.
C.) and under a range of reducing and oxidizing conditions. A
preferable oxygen storage material is a mixture of ceria and
zirconia; more preferably a mixture of (1) ceria, zirconia, and
lanthanum or (2) ceria, zirconia, neodymium, and praseodymium.
[0078] According to an embodiment, if a catalyst of the present
invention comprises at least one oxygen storage material, the
catalyst may comprise about 10 to about 90 weight percent oxygen
storage material, preferably about 20 to about 80 weight percent,
more preferably about 40 to about 75 weight percent. The weight
percent of the oxygen storage material is on the basis of the
oxides.
[0079] Various amounts of any of the washcoats of the present
invention may be coupled with a substrate, preferably an amount
that covers most of, or all of, the surface area of a substrate. In
an embodiment, about 80 g/L to about 250 g/L of a washcoat may be
coupled with a substrate.
[0080] In an embodiment, a washcoat may be formed on the substrate
by suspending the oxide solids in water to form an aqueous slurry
and depositing the aqueous slurry on the substrate as a
washcoat.
[0081] Other components may optionally be added to the aqueous
slurry. Other components such as acid or base solutions or various
salts or organic compounds may be added to the aqueous slurry to
adjust the rheology of the slurry and/or enhance binding of the
washcoat to the substrate. Some examples of compounds that can be
used to adjust the rheology include, but are not limited to,
ammonium hydroxide, aluminum hydroxide, acetic acid, citric acid,
tetraethylammonium hydroxide, other tetralkylammonium salts,
ammonium acetate, ammonium citrate, glycerol, commercial polymers
such as polyethylene glycol, polyvinyl alcohol and other suitable
polymers.
[0082] The slurry may be placed on the substrate in any suitable
manner. For example, without limitation, the substrate may be
dipped into the slurry, or the slurry may be sprayed on the
substrate. Other methods of depositing the slurry onto the
substrate known to those skilled in the art may be used in
alternative embodiments. If the substrate is a monolithic carrier
with parallel flow passages, the washcoat may be formed on the
walls of the passages. Gas flowing through the flow passages can
contact the washcoat on the walls of the passages as well as
materials that are supported on the washcoat.
[0083] It is believed that the oxygen storage material may improve
the rheology of the washcoat slurry. Such an improvement may be
seen in process control and/or manufacture of the catalyst system.
The enhanced rheology of the washcoat slurry that may be due to the
presence of the oxygen storage material may enhance the adhesion of
the washcoat slurry to the substrate.
Catalyst System Architecture
[0084] The catalyst system of the present invention may have one of
the following three architectures. In one embodiment, a catalyst
system may comprise a substrate (1) and a washcoat (2), wherein the
washcoat comprises at least one catalyst. See FIG. 1 (Architecture
1). In another embodiment, a catalyst system may comprise a
substrate (1), a washcoat (2), and an overcoat (3), wherein the
washcoat (2) and overcoat (3) each comprise at least one catalyst.
See FIG. 2 (Architecture 2). In another embodiment, a catalyst
system may comprise a substrate (1), a washcoat (2), and an
overcoat (3), wherein the overcoat (3) comprises at least one
catalyst, but the washcoat (2) is free of catalyst, preferably
completely free. See FIG. 3 (Architecture 3). The washcoat (2) of
the third catalyst system architecture comprises a carrier material
oxide or mixtures thereof. Other components known to one of
ordinary skill in the art may be included.
[0085] The Architectures depicted in FIGS. 1-3 show how the layers
are applied in order, but the end product may not have the layers
as depicted due to, without limitation, the reactions that may
occur between the layers.
[0086] In the event that a washcoat (2) or an overcoat (3) with a
catalyst is required, the washcoat (2) may be deposited in three
different ways. First, depositing all desired components in one
step. Or second, depositing components without a catalyst, then
separately depositing at least one impregnation component and
heating (this separate deposit is also referred to as an
impregnation step). The impregnation component comprises, without
limitation, transition metals, alkali and alkaline earth metals,
cerium, lanthanum, yttrium, lanthanides, actinides, or mixtures
thereof. The impregnation step converts metal salts into metal
oxides creating a washcoat (2) comprising a catalyst. Third,
depositing all desired components at once, including metal salts
and then heating to convert the metals salts to metal oxides.
[0087] The overcoat (3) is typically applied after treating the
washcoat (2), but treating is not required prior to application of
the overcoat (3) in every embodiment. Preferably, the overcoat (3)
is applied after the washcoat (2).
[0088] According to an embodiment, a catalyst system comprises a
substrate (1) and one or more catalyst selected from the group
consisting of a ZPGM transition metal catalyst, a mixed metal oxide
catalyst, and a zeolite catalyst.
ZPGM Transition Metal Catalyst
[0089] According to an embodiment, a catalyst system of the present
invention comprises a ZPGM transition metal catalyst. A ZPGM
transition metal catalyst comprises one or more transition metals.
Preferably the transition metal is copper, nickel, iron, manganese,
silver, cobalt, tungsten, niobium, molybdenum, or chromium; more
preferably copper, nickel, iron, or manganese; most preferably
copper, nickel, or cobalt.
[0090] According to an embodiment, the ZPGM transition metal
catalyst optionally comprises one or more of a carrier material
oxide. Preferably the catalyst comprises a perovskite, a spinel, a
lyonsite, an oxygen storage material, alumina, or mixtures thereof;
more preferably a spinel, an oxygen storage material, alumina, or
mixtures thereof; most preferably at least one spinel and at least
one oxygen storage material, or alumina and at least one oxygen
storage material.
[0091] If a catalyst of the present invention comprises at least
one oxygen storage material, the catalyst may comprise about 10 to
about 90 weight percent oxygen storage material, preferably about
20 to about 80 weight percent, more preferably about 40 to about 75
weight percent. The weight percent of the oxygen storage material
is on the basis of the oxides.
[0092] With any of the catalyst systems described herein, the
catalysts may optionally further comprise one or more of a
transition metal, alkaline earth metal, ceria, and mixtures
thereof. Preferably, the transition metal is iron, manganese, or
mixtures thereof. Preferably, the alkaline earth metal is
magnesium, barium, or mixtures thereof.
[0093] According to an embodiment, the catalyst, referred to as
"Type H", comprises at least one transition metal and at least one
carrier material oxide. The transition metals may be a single
transition metal, or a mixture of transition metals which includes,
but is not limited to, chromium, manganese, iron, cobalt, nickel,
copper, silver, niobium, molybdenum, and tungsten. The preferred
transition metals are copper, nickel and cobalt. The total amount
of the transition metal(s) are present in about 5% to about 50% by
weight of the total catalyst weight and may be present in any ratio
of transitional metals.
[0094] According to an embodiment, the catalyst, referred to as
"Type D", comprises copper and one or more carrier material oxides.
Optionally, additional transition metals may be included. The
copper may be applied through impregnation as discussed herein. The
copper in the catalyst may be present in about 5% to about 50% by
weight, preferably about 5% to about 30%, more preferably about 15%
by weight.
[0095] According to an embodiment, a catalyst system, referred to
as "ZPGM-6", comprises a substrate, a washcoat, and an overcoat.
The substrate comprises cordierite. The washcoat comprises a spinel
and at least one oxygen storage material, preferably the oxygen
storage material is a mixture of cerium, zirconium, and lanthanum.
The spinel in this embodiment comprises magnesium aluminum oxides.
Additionally, the oxygen storage material and the spinel may be
present in the washcoat in a ratio of 40 to about 60 by weight. If
an impregnation step is required, copper, cerium, zirconium, and
lanthanum may be added and heated to convert metal salts into metal
oxides that create a washcoat comprising the catalyst. The overcoat
comprises copper oxide, a spinel, and at least one oxygen storage
material, preferably the oxygen storage material comprises a
mixture of cerium, zirconium, neodymium, and praseodymium. The
spinel in this embodiment comprises magnesium aluminum oxides. The
spinel and oxygen storage material of the overcoat may be present
in the overcoat in a ratio of about 60 to about 40. The copper in
the overcoat is present in about 5% to about 50%, preferably about
10% to about 16% by weight.
[0096] According to an embodiment, a catalyst system, referred to
as "ZPGM-5", comprises a substrate, a washcoat, and an overcoat.
The substrate comprises cordierite. The washcoat comprises
lanthanum-doped aluminum oxide and at least one oxygen storage
material, preferably the oxygen storage material comprises a
mixture of cerium, zirconium, neodymium, and praseodymium.
Additionally, the oxygen storage material and the lanthanum-doped
aluminum oxide may be present in the washcoat in a ratio of about
40 to about 60. The optional impregnation components comprise
copper, cerium, zirconium, and lanthanum. The overcoat comprises
copper oxide, lanthanum-stabilized aluminum oxide, and at least one
oxygen storage material, preferably the oxygen storage material
comprises a mixture of cerium, zirconium, neodymium, and
praseodymium. The aluminum oxide and oxygen storage material of the
overcoat may be present in the overcoat in a ratio of about 75 to
about 25. The copper in the overcoat is present in about 5% to
about 50%, preferably about 15% by weight.
[0097] According to an embodiment, a catalyst system, referred to
as "ZPGM-4", comprises a substrate, a washcoat, and an overcoat.
The washcoat comprises tin aluminum oxide and at least one oxygen
storage material, preferably the oxygen storage material comprises
a mixture of cerium, zirconium, neodymium, and praseodymium. The
tin aluminum oxide and the oxygen storage material may be present
in the washcoat in a ratio of from about 25:75 to about 75:25,
preferably in a ratio of about 60 to about 40. The optional
impregnation components comprise copper, cerium, zirconium, and
lanthanum. The overcoat comprises aluminum, copper, and at least
one oxygen storage material, preferably the oxygen storage material
comprises a mixture of cerium, zirconium, and lanthanum. The
aluminum oxide and oxygen storage material may be present in the
overcoat in a ratio of about 60 to about 40. According to an
embodiment, there is about 5% to about 30% copper by weight in the
overcoat, preferably about 10% to about 20%, more preferably about
12%.
[0098] According to an embodiment, a catalyst system, referred to
as "ZPGM-3", comprises a substrate and a washcoat. The washcoat
comprises copper, tin aluminum oxide, and at least one oxygen
storage material, preferably the oxygen storage material comprises
a mixture of cerium, zirconium, neodymium, and praseodymium. The
tin aluminum oxide and the oxygen storage material may be present
in the washcoat in a ratio of about 60 to about 40. If an
impregnation step is used, the impregnation components comprise
copper, cerium, zirconium, and lanthanum. The cerium, zirconium,
and lanthanum may be present in the washcoat in a ratio of about 60
to about 30 to about 10. The washcoat may comprise additional
transition metals. According to an embodiment, there is about 5% to
about 30% copper by weight in the washcoat, preferably about 10% to
about 20%, more preferably about 12%.
[0099] According to an embodiment, a catalyst system, referred to
as "ZPGM-2", comprises a substrate and a washcoat. The washcoat may
comprise, without limitation, copper, aluminum oxide, and at least
one oxygen storage material, preferably the oxygen storage material
is a mixture of cerium, zirconium, and lanthanum. The aluminum
oxide and the oxygen storage material may be present in the
washcoat in a ratio of about 60 to about 40. The copper in the
washcoat may be about 5% to about 20% copper by weight, preferably
about 8%. The washcoat coat may optionally comprise additional
transitional metals and/or ceria.
[0100] According to an embodiment, a catalyst system, referred to
as "ZPGM-1", comprises a substrate and a washcoat. The washcoat
comprises at least one carrier material oxide and a perovskite;
preferably the carrier material oxide comprises an oxygen storage
material, more preferably comprises one or more selected from the
group consisting of cerium, zirconium, lanthanum, neodymium,
praseodymium, and mixtures thereof, and the perovskite preferably
is a mixture of cerium, lanthanum, manganese and copper, having the
specific formula
Ce.sub.0.6La.sub.0.4Mn.sub.0.6Cu.sub.0.4O.sub.3.
[0101] According to an embodiment, the catalyst, referred to as
"Type A", comprises at least one transition metal, at least one
alkaline earth metal, cerium, and at least one carrier material
oxide. The transition metal, alkaline earth metal and cerium are
present in about 5% to about 50% by weight in any ratio of the
three components. Preferably, the alkaline earth metals comprise
one or more selected from the group consisting of magnesium,
calcium, barium, and strontium. The transition metals may be a
single transition metal, or a mixture of transition metals which
include, but is not limited to, chromium, manganese, iron, cobalt,
nickel, copper, niobium, molybdenum, and tungsten.
[0102] According to an embodiment, the catalyst, referred to as
"Type C", comprises at least one transition metal, at least one
alkaline earth metal, and at least one carrier material oxide. The
transition metal may be a single transition metal, or a mixture of
transition metals which include, but is not limited to, chromium,
manganese, iron, cobalt, nickel, copper, niobium, molybdenum,
tungsten, and silver. The alkaline earth metal may be, but is not
limited to, magnesium, calcium, barium or strontium. The preferred
transition metals are copper, nickel, and cobalt, while the
preferred alkaline earth metals are barium and strontium. The
alkaline earth metal and the transition metal may be present in a
molar ratio of about 1:10 to 1:1 and at about 2% to about 50%
weight of the catalyst.
[0103] According to an embodiment, the catalyst, referred to as
"Type E", comprises at least one transition metal and a perovskite
having the formula ABO.sub.3. The transition metal may be, but is
not limited to, copper, nickel, cobalt, manganese, iron, chromium,
niobium, molybdenum, tungsten, and silver. Preferably, the
transition metals are copper, nickel, and/or cobalt. "A" comprises
lanthanum, cerium, magnesium, calcium, barium, strontium,
lanthanides, actinides, or a mixture thereof. "B" comprises iron,
manganese, copper, nickel, cobalt, cerium, or mixtures thereof. The
transition metal(s) is present in about 2% to about 30% by
weight.
[0104] According to one embodiment, the Type E catalyst comprises a
perovskite (ABO.sub.3), at least one transition metal, and at least
one a carrier material oxide. The transition metal may be a single
transition metal, or a mixture of transition metals which includes,
but is not limited to, chromium, manganese, iron, cobalt, nickel,
copper, niobium, molybdenum, tungsten, silver, or mixtures thereof.
The perovskite and transition metal are present in about 5% to
about 50% by weight.
[0105] According to an embodiment, the catalyst, referred to as
"Type G", comprises at least one transition metal and a spinel
having the formula AB.sub.2O.sub.4. The transition metal may be,
but is not limited to, copper, nickel, cobalt, manganese, iron,
chromium, niobium, molybdenum, tungsten, and silver. The preferred
transition metals include, copper, nickel, and cobalt; more
preferably copper. "A" and "B" each comprise aluminum, magnesium,
manganese, gallium, nickel, copper, cobalt, iron, chromium,
niobium, titanium, tin, or mixtures thereof. A preferred spinel is
MgAl.sub.2O.sub.4. The transition metal(s) are present in about 2%
to about 30% by weight.
[0106] According to one embodiment, the Type G catalyst comprises a
spinel (AB.sub.2O.sub.4), a transition metal, and a carrier
material oxide. The transition metal may be a single transition
metal, or a mixture of transition metals which includes, but is not
limited to, chromium, manganese, iron, cobalt, nickel, copper,
niobium, molybdenum, tungsten, and/or silver. A preferred spinel is
MgAl.sub.2O.sub.4. The spinel and transition metal(s) are present
in about 5% to about 50% by weight.
Mixed Metal Oxide Catalyst
[0107] According to an embodiment, a catalyst may be a mixed metal
oxide catalyst, which comprises at least one transition metal and
at least one other metal. The other metals of the mixed metal oxide
may include, but are not limited to alkali and alkaline earth
metal, lanthanides, or actinides. For example, the mixed metal
oxide may be a spinel, a perovskite, a delafossite, a lyonsite, a
garnet, or a pyrochlore.
[0108] According to an embodiment, the catalyst, referred to as
"Type B", comprises a perovskite having the formula ABO.sub.3 or a
related structure with the general formula
A.sub.a-xB.sub.xMO.sub.b, wherein "a" is 1 or 2, "b" is 3 when "a"
is 1 or "b" is 4 when "a" is 2, and "z" is a number defined by
0.1.ltoreq.x<0.7. "A" comprises lanthanum, lanthanides,
actinides, cerium, magnesium, calcium, barium, strontium, or
mixtures thereof. "B" comprises a single transition metal, or a
mixture of transition metals including but not limited to iron,
manganese, copper, nickel, cobalt, and cerium, or mixture thereof.
According to an embodiment, the catalyst may have the formula
AMn.sub.1-xCu.sub.xO.sub.3, wherein "A" is lanthanum, cerium,
barium, strontium, a lanthanide, or an actinide and "x" is 0 to
1.
[0109] According to another embodiment, the Type B catalyst may
have the formula ACe.sub.1-xCu.sub.xO.sub.3, wherein "A" is barium,
strontium, or calcium, and "x" is 0 to 1. According to an
embodiment, about 10 g/L to about 180 g/L of the formula ABO.sub.3
may be coupled with the substrate.
[0110] According to one embodiment, the Type B catalyst comprises a
perovskite (ABO.sub.3) or related structure (with general formula
A.sub.a-xB.sub.xMO.sub.b) and one or more of a carrier material
oxide. The perovskite or related structure is present in about 5%
to about 50% by weight.
[0111] According to an embodiment, the catalyst, referred to as
"Type F", comprises a spinel having the formula AB.sub.2O.sub.4.
"A" and "B" of the formula is aluminum, magnesium, manganese,
gallium, nickel, copper, cobalt, iron, chromium, titanium, tin, or
mixtures thereof.
[0112] According to an embodiment, the Type F catalyst comprises a
spinel and a carrier material oxide. The spinel is present in about
5% to about 50% by weight.
Zeolite Catalyst
[0113] According to an embodiment, a catalyst may be a zeolite
catalyst comprising a zeolite or mixture of zeolites and at least
one transition metal. A zeolite is mixed aluminosillicates with
regular interconnected pores. The zeolite includes, but is not
limited to ZSM5, heulandite, chabazite, or mixtures thereof,
preferably ZSM5. According to an embodiment, the catalyst, referred
to as "Type I" comprises at least one transition metal impregnated
into a zeolite or mixtures of zeolite. The transition metal(s) may
be a single transition metal or a mixture of transition metal which
includes, but is not limited to, chromium, gallium, manganese,
iron, cobalt, nickel, copper, niobium, molybdenum, tungsten, and
silver. Preferably, the transition metals are selected from the
group consisting of copper, nickel, gallium, cobalt, and mixtures
thereof. The transition metals may be present in about 3% to about
25% by weight in any ratio of transition metals.
[0114] According to an embodiment, the catalysts of the present
invention may reduce pollutants emitted from exhaust. This is done
by passing exhaust substantially through a catalyst system, such
that the flowing exhaust reduces the pollutants. The exhaust
includes, but is not limited to exhaust from an automobile,
vehicle, factory, train, airplane, building, and laboratory.
Pollutants are any compounds, substances, gases, or waste that
causes damage to water, air, land, and any other part of the
environment, including carbon monoxide, hydrocarbons, nitrogen
oxides, and sulfur.
[0115] The catalysts of the present invention to decrease the
amount of nitrogen oxide emissions. For example:
NO+1/2O.sub.2.fwdarw.NO.sub.2 and
6NO.sub.2+8NH.sub.3.fwdarw.7N.sub.2+12H.sub.2O. The catalyst also
decreases the amount of the unburned hydrocarbons and carbon
monoxide by oxidizing them. For example:
2C.sub.xH.sub.y+(2x+y/2)O.sub.2.fwdarw.2xCO.sub.2+yH.sub.2O or
2CO+O.sub.2.fwdarw.2CO.sub.2. The catalysts may also decrease the
amount of sulfur emissions.
[0116] According to an embodiment, a catalyst system comprises a
first catalyst system and a second catalyst system. The first
catalyst system may be any catalyst described herein. The second
catalyst system comprises a catalyst comprising at least one
platinum group metal, wherein the catalyst may comprise any
platinum group metal known in the art, including, but not limited
to mixtures of platinum group metals and carrier material oxides.
The first catalyst system and the second catalyst system may be in
an orientation such that a gas stream is capable of passing through
the first catalyst system followed by the second catalyst system in
series or vice versa. Further, a catalyst system may comprise more
than a first and a second catalyst system, e.g. a third catalyst
system.
Preparation of a Zero Platinum Group Metal Catalyst by
Impregnation
[0117] A washcoat having the properties discussed herein may be
prepared by methods well known in the art. The washcoat may
comprise any of the catalysts and/or additional components
described herein. The washcoat is deposited on a substrate and is
treated. The treating is done at a temperature between 300.degree.
C. and 700.degree. C., preferably about 550.degree. C. The treating
may last from about 2 to about 6 hours, preferably about 4 hours.
After the washcoat and the substrate are treated, they are cooled
to about room temperature. After the washcoat and the substrate are
cooled, the washcoat is impregnated with at least one impregnation
component. The impregnation component includes, without limitation,
a transition-metal salt or salts being dissolved in water and
impregnated on the washcoat. Following the impregnation step, the
washcoat with the impregnation components are treated. The treating
may be performed at about 300.degree. C. to about 700.degree. C.,
preferably about 550.degree. C. The treating may last from about 2
to about 6 hours, preferably about 4 hours.
[0118] According to an embodiment, the substrate, the washcoat, and
the impregnation components may be treated to form the catalyst
composition before or after the washcoat and/or the impregnation
components are added to the substrate. In an embodiment, the
washcoat and the impregnation component may be treated before
coating.
[0119] The impregnation method may be performed on an overcoat.
After depositing the overcoat, the overcoat is impregnated with at
least one impregnation component. The impregnation component
includes, without limitation, a transition-metal salt or salts
being dissolved in water and impregnated on the overcoat. Following
the impregnation step, the overcoat with the impregnation
components are treated. The treating may be performed at about
300.degree. C. to about 700.degree. C., preferably about
550.degree. C. The treating may last from about 2 hours to about 6
hours, preferably about 4 hours.
Preparation of a Zero Platinum Group Metal Catalyst by
Precipitation
[0120] The method of precipitation includes precipitating a
transition metal salt or salts on a washcoat. The transition metal
salt or salts may be precipitated with, but is not limited to
NH.sub.4OH, (NH.sub.4).sub.2CO.sub.3, tetraethylammonium hydroxide,
other tetralkylammonium salts, ammonium acetate, or ammonium
citrate. The washcoat may be any washcoat described herein. Next,
the precipitated transition metal salt or salts and washcoat are
treated. The treating may be from about 2 hours to about 24 hours.
Next, the precipitated transition metal salt or salts and the
washcoat are deposited on a substrate followed by treating for
about 2 hours to about 6 hours, preferably about 4 hours at a
temperature of about 300.degree. C. to about 700.degree. C.,
preferably about 550.degree. C. Optionally, after treating, an
overcoat may be deposited on the treated precipitated transition
metal salt or salts and washcoat and treated again. The overcoat
may be treated for about 2 hours to about 6 hours, preferably about
4 hours and at a temperature of about 300.degree. C. to about
700.degree. C., preferably about 550.degree. C.
Preparation of a Zero Platinum Group Metal Catalyst by
Co-Milling
[0121] A catalyst and a carrier material oxide are milled together.
The catalyst can be synthesized by any chemical technique such as,
but not limited to solid-state synthesis, precipitation, or any
other technique known in the art. The milled catalyst and carrier
material oxide are deposited on a substrate in the form of a
washcoat and then treated. The treatment may be from about 2 hours
to about 6 hours, preferably about 4 hours and at a temperature of
about 300.degree. C. to about 700.degree. C., preferably about
550.degree. C. Optionally, an overcoat may be deposited on the
treated catalyst after cooling to about room temperature. The
overcoat, washcoat and substrate are treated for about 2 hours to
about 6 hours, preferably about 4 hours and at a temperature of
300.degree. C. to about 700.degree. C., preferably about
550.degree. C.
[0122] The following examples are intended to illustrate, but not
to limit, the scope of the invention. It is to be understood that
other procedures known to those skilled in the art may
alternatively be used.
EXAMPLE 1
Pore Volume and Surface Area Measurements for Zero Platinum Group
Metal Catalysts
[0123] FIG. 4 shows the measured pore volume for the fresh catalyst
systems ZPGM-1 through ZPGM-5 and FIG. 5 shows the measured pore
volume for the aged catalyst systems ZPGM-1 through ZPGM-5. The
aged catalyst systems were aged at 950.degree. C. for 16 hours with
10% H.sub.2O and air. The y-axis on the right side of FIG. 4 is for
the pore volume (cm.sup.3/g) of ZPGM-1 only.
[0124] The pore volumes were measured using a Micromeritics.RTM.
(Norcross, Ga.) TriStar 3000 gas adsorption analyzer at 77K. The
pore volumes were obtained from the nitrogen adsorption isotherms
using the Barrett-Joiner-Halenda (BJH) method (E. P. Barrett, L. G.
Joyner, P. P. Halenda, "The determination of pore volume and area
distributions in porous substances. I. Computations from nitrogen
isotherms," J. Am. Chem. Soc. (1951), 73, 373-380).
[0125] The results in FIGS. 4 and 5 show that the pore volume
decreases for all the catalyst systems (ZPGM-1 through ZPGM-5) upon
aging. The average pore volume for the fresh ZPGM-1 decreases from
0.106 cm.sup.3/g to 0.017 cm.sup.3/g for the aged catalyst.
Similarly, the average pore volume for the fresh ZPGM-2 decreases
from 0.173 cm.sup.3/g to 0.116 cm.sup.3/g for the aged catalyst.
Again, the average pore volume for the fresh ZPGM-3 decreases from
0.107 cm.sup.3/g to 0.010 cm.sup.3/g for the aged catalyst. The
average pore volume for the fresh ZPGM-4 decreases from 0.190
cm.sup.3/g to 0.142 cm.sup.3/g for the aged catalyst. The average
pore volume for the fresh ZPGM-5 decreases from 0.213 cm.sup.3/g to
0.122 cm.sup.3/g for the aged catalyst.
EXAMPLE 2
Surface Area Analysis for Fresh and Aged Catalyst Systems ZPGM-1
through ZPGM-5
[0126] The surface areas for the fresh and aged ZPGM catalyst
systems are presented in FIG. 6. The aged catalyst systems were
aged at 950.degree. C. for 16 hours with 10% H.sub.2O and air.
[0127] The surface areas were measured using a Micromeritics.RTM.
(Norcross, Ga.) TriStar 3000 gas adsorption analyzer at 77K. The
surface areas were calculated using the BET (Brunauer, Emmitt and
Teller) method (S. Brunauer, P. H. Emmett and E. Teller, J. Am.
Chem. Soc., 1938, 60, 309).
[0128] The results in FIG. 6 show that the surface area decreases
for all catalyst systems (ZPGM-1 through ZPGM-5) upon aging. The
surface area decreases from 18.72 m.sup.2/g for the fresh ZPGM-1 to
2.76 m.sup.2/g for the aged catalyst. Similarly, the surface area
decreases from 38.60 m.sup.2/g for the fresh ZPGM-2 to 15.48
m.sup.2/g for the aged catalyst. The surface area decreases from
30.78 m.sup.2/g for the fresh ZPGM-3 to 16.71 m.sup.2/g for the
aged catalyst. The surface area decreases from 46.95 m.sup.2/g for
the fresh ZPGM-4 to 22.06 m.sup.2/g for the aged catalyst. The
surface area decreases from 53.45 m.sup.2/g for the fresh ZPGM-5 to
24.02 m.sup.2/g for the aged catalyst.
EXAMPLE 3
X-Ray Diffraction Analysis for ZPGM Transition Metal Catalysts
[0129] FIGS. 7-12 show the X-ray diffraction (XRD) patterns of
fresh and aged catalyst systems ZPGM-1 through ZPGM-6; the aged
catalyst systems were aged at 950.degree. C. for 16 hrs with 10%
H.sub.2O and air.
[0130] The XRD analysis was conducted to determine the crystalline
phases present for each catalyst system. The XRD patterns were
measured on a Rigaku.RTM. powder diffractometer (MiniFlex.TM.)
using Cu Ka radiation in the 2-theta range of 20-70.degree. with a
step size of 0.05.degree. and a dwell time of 2 s. The tube voltage
and current were set at 40 kV and 30 mA, respectively. The
resulting diffraction patterns were analyzed using the
International Centre for Diffraction Data (ICDD) database.
[0131] FIG. 7 shows the XRD spectra of the fresh and aged ZPGM-1
catalyst system, Ce.sub.0.6La.sub.0.4Mn.sub.0.6Cu.sub.0.4O.sub.3,
shows the presence of the perovskite (open circles) and fluorite
(filled squares) structures. The fluorite and the perovskite
structures are larger in the aged sample as evidenced by the
sharper peaks.
[0132] FIG. 8 shows the XRD patterns of fresh and aged ZPGM-2
catalyst system, 8% Cu impregnated on
Al.sub.2O.sub.3+Ce.sub.0.64Zr.sub.0.21La.sub.0.15O.sub.2 (60:40
weight ratio of Al.sub.2O.sub.3 to
Ce.sub.0.64Zr.sub.0.21La.sub.0.15O.sub.2) (160 g/ml). The XRD
spectrum of the fresh ZPGM-2 catalyst system shows the presence of
the fluorite structure (open squares), alumina (A) and CuO (filled
circles). The aged ZPGM-2 catalyst system shows fluorite (open
squares), CuAl.sub.2O.sub.4 (filled diamonds) and alumina (A). The
fluorite structure is larger in the aged sample as evidenced by the
sharper peaks.
[0133] FIG. 9 shows the XRD patterns of fresh and aged ZPGM-3
catalyst system, 8% Cu+6.1% Ce+2.4% Zr+1.5% La impregnated on 15%
Sn--Al.sub.2O.sub.3+Ce.sub.0.6Zr.sub.0.3Nd.sub.0.05Pr.sub.0.05O.sub.2
(60:40 weight ratio of Sn--Al.sub.2O.sub.3 to
Ce.sub.0.6Zr.sub.0.3Nd.sub.0.05Pr.sub.0.05O.sub.2) (200 g/L). The
XRD of the fresh ZPGM-3 catalyst system shows the presence of the
fluorite structure (open circles), ZrO.sub.2 (open squares),
alumina (A) and CuO (filled circles). The aged ZPGM-3 catalyst
system shows fluorite (open circles), ZrO.sub.2 (open squares),
SnO.sub.2 (filled circles), CuAl.sub.2O.sub.4 (filled diamonds) and
alumina (A). The cordierite peak in the aged sample is from the
substrate. During the aging the tin oxide dissociates from the
alumina, the Cu reacts with the Al.sub.2O.sub.3 to form
CuAl.sub.2O.sub.4.
[0134] FIG. 10 shows the XRD patterns of fresh and aged ZPGM-4
catalyst system, which is composed of an overcoat containing 12% Cu
impregnated on
Ce.sub.0.6Zr.sub.0.21La.sub.0.15O.sub.2+Al.sub.2O.sub.3 (60:40
weight ratio of Ce.sub.0.6Zr.sub.0.21La.sub.0.15O.sub.2 to
Al.sub.2O.sub.3) and a washcoat containing 8% Cu+6.1% Ce+2.4%
Zr+1.5% La impregnated impregnated on 15%
Sn--Al.sub.2O.sub.3+Ce.sub.0.6Zr.sub.0.3Nd.sub.0.05Pr.sub.0.05O.sub.2
(60:40 weight ratio of Sn--Al.sub.2O.sub.3 to
Ce.sub.0.6Zr.sub.0.3Nd.sub.0.05O.sub.2). The XRD spectrum of the
fresh ZPGM-4 catalyst system shows the presence of the fluorite
structure (filled circles), CeO.sub.2 (open squares), alumina (A)
and CuO (filled squares). The aged ZPGM-4 catalyst system shows
fluorite (filled circles), CeO.sub.2 (open squares), SnO.sub.2
(open circles), CuAl.sub.2O.sub.4 (filled diamonds) and alumina
(A). During the aging the tin oxide dissociates from the alumina,
the Cu reacts with the Al.sub.2O.sub.3 to form
CuAl.sub.2O.sub.4.
[0135] FIG. 11 shows the XRD patterns of fresh and aged ZPGM-5
catalyst system, which is composed of an overcoat containing 12.4%
CuO impregnated on
La--Al.sub.2O.sub.3+Ce.sub.0.6Zr.sub.0.3Nd.sub.0.05Pr.sub.0.05O.sub.2
(25:75 weight ratio of La--Al.sub.2O.sub.3 to
Ce.sub.0.6Zr.sub.0.3Nd.sub.0.05Pr.sub.0.05O.sub.2) (65 g/L) and a
washcoat containing 8% Cu+6.1% Ce+2.4% Zr+1.5% La impregnated on
La--Al.sub.2O.sub.3+Ce.sub.0.6Zr.sub.0.3Nd.sub.0.05Pr.sub.0.05O.sub.2
(60:40 weight ratio of La--Al.sub.2O.sub.3 to
Ce.sub.0.6Zr.sub.0.3Nd.sub.0.05Pr.sub.0.05O.sub.2) (180 g/L). The
XRD spectrum of the fresh ZPGM-5 catalyst system shows the presence
of the fluorite structure (filled circles) and alumina (A). The
aged ZPGM-5 catalyst system shows fluorite (filled circles),
CuAl.sub.2O.sub.4 (filled diamonds) and alumina (A). During the
aging the Cu reacts with the Al.sub.2O.sub.3 to form
CuAl.sub.2O.sub.4.
[0136] FIG. 12 shows the XRD patterns of fresh and aged ZPGM-6
catalyst system, which is composed of an overcoat containing 10%
Cu+12% Ce impregnated on MgAl.sub.2O.sub.4+16% Cu impregnated on
Ce.sub.0.6Zr.sub.0.3Nd.sub.0.05Pr.sub.0.05O.sub.2 (60:40 weight
ratio of Ce impregnated on MgAl.sub.2O.sub.4 to 16% Cu impregnated
on Ce.sub.0.6Zr.sub.0.3Nd.sub.0.05Pr.sub.0.05O.sub.2) (65 g/L) and
a washcoat containing 4% Cu+6.1% Ce+2.4% Zr+1.5% La impregnated on
MgAl.sub.2O.sub.4+Ce.sub.0.64Zr.sub.0.21La.sub.0.15O.sub.2 (60:40
weight ratio of MgAl.sub.2O.sub.4 to
Ce.sub.0.64Zr.sub.0.21La.sub.0.15O.sub.2) (180 g/L). The XRD
spectrum of the fresh ZPGM-6 catalyst system shows the presence of
two fluorite structures (filled and open circles), and
MgAl.sub.2O.sub.4 (open diamonds). The aged ZPGM-6 catalyst system
shows two fluorite structures (filled and open circles),
MgAl.sub.2O.sub.4 (open diamonds), CuAl.sub.2O.sub.4 (filled
diamonds), and CuO (filled squares). During the aging the CZL and
CuO became more crystalline, and some CuAl.sub.2O.sub.4 formed.
EXAMPLE 4
Sweep Test for Catalyst Systems ZPGM-1 through ZPGM-6
[0137] FIGS. 13-18 show the sweep test results for catalyst systems
ZPGM-1 through ZPGM-6 (as described above in Examples 3-8),
respectively. The sweep test was performed with an inlet
temperature of 600.degree. C., an air/fuel span of .+-.0.2 and a
cycle frequency of 1 Hz. A sweep test indicates the catalyst
performance at various R-values (moles of reductant divided by
moles of oxidant). High conversions over a large range of R-values
indicate a promising catalyst because it can perform well under
rich (R-values>1) and lean (R-values<1) engine conditions.
The aged catalyst systems were aged at 1050.degree. C. for 10 hrs
cycling between a 56 second rich segment and a 4 second lean
segment.
[0138] FIG. 13 shows the sweep test results for the fresh and aged
ZPGM-1 catalyst system. The sweep results for the fresh catalyst
show that the CO conversion decreases with R-values>1.05, while
the hydrocarbon (HC) conversion decreases with increasing R-values.
The NO conversion increases with R-value>0.85. The catalytic
properties for CO, hydrocarbons and NO decrease after aging; the NO
conversion is <5% over the entire R-value range tested. The CO
conversion of the aged ZPGM-1 decreases with increasing R-value.
The HC conversion for the aged ZPGM-1 is best for R-values between
0.95 and 1.05.
[0139] FIG. 14 shows the sweep test results for the fresh and aged
ZPGM-2 catalyst system. The sweep results for the fresh catalyst
show that the CO conversion decreases with R-values>1.05, while
the hydrocarbon (HC) conversion decreases with increasing R-values.
The NO conversion increases with R-value>0.85. The catalytic
properties for CO, hydrocarbons and NO decrease after aging. The CO
and HC conversions of the aged ZPGM-2 decrease with increasing
R-value. The NO conversion is the highest at R=0.85, for the aged
ZPGM-2 catalyst system.
[0140] FIG. 15 shows the sweep test results for the fresh and aged
ZPGM-3 catalyst system. The sweep results for the fresh catalyst
show that the CO conversion decreases with R-values>1.05, while
the hydrocarbon (HC) conversion decreases with increasing R-values.
The NO conversion increases with increasing R-values. The catalytic
properties for CO, hydrocarbons and NO decrease after aging. The CO
and HC conversions of the aged ZPGM-3 decrease with increasing
R-value. The NO conversion for the aged ZPGM-3 increases with
R-values>0.95.
[0141] FIG. 16 shows the sweep test results for the fresh and aged
ZPGM-4 catalyst system. The sweep results for the fresh catalyst
show that the CO conversion decreases with R-values>0.975, while
the hydrocarbon (HC) conversion decreases with increasing R-values.
The NO conversion increases with increasing R-values. The catalytic
properties for CO, hydrocarbons and NO decrease after aging. The CO
and HC conversions of the aged ZPGM-4 decrease with increasing
R-value. The NO conversion for the aged ZPGM-4 increases with
R-values>0.95.
[0142] FIG. 17 shows the sweep test results for the fresh and aged
ZPGM-5 catalyst system. The sweep results for the fresh catalyst
show that the CO conversion decreases with R-values>0.975, while
the hydrocarbon (HC) conversion decreases with increasing R-values.
The NO conversion increases with increasing R-values. The catalytic
properties for CO, hydrocarbons and NO decrease after aging. The CO
and HC conversions of the aged ZPGM-5 decrease with increasing
R-value. The NO conversion for the aged ZPGM-5 increases with
R-values>1.05.
[0143] FIG. 18 shows the sweep test results for the fresh and aged
ZPGM-6 catalyst system. The sweep results for the fresh catalyst
show that the CO conversion decreases with R-values>0.975, while
the hydrocarbon (HC) conversion decreases with increasing R-values.
The NO conversion increases with increasing R-values. The catalytic
properties for CO, hydrocarbons and NO decrease after aging. The CO
and HC conversions of the aged ZPGM-6 decrease with increasing
R-value. The NO conversion for the aged ZPGM-6 increases with
R-values>0.975.
EXAMPLE 5
Light-Off Test for Type D or Type H ZPGM Transition Metal
Catalysts
[0144] FIGS. 19-21 show the light-off test results for examples of
Type D or Type H ZPGM Transition Metal Catalysts. It should be
noted that a catalyst may fall into one or more types, such as
here, where the catalyst is both Type D and Type H. A light-off
test was performed on aged (800.degree. C. for 16 hours, composed
of a 56 second rich segment and a 4 second lean segment) catalysts
of the present invention. The test was performed by increasing the
temperature from about 100.degree. C. to 640.degree. C. at
R-value=1.05 and R-value=1.5. The light-off test measures the
conversions of nitrogen oxide, carbon monoxide, and hydrocarbons as
a function of the catalyst system temperature. For a specific
temperature, a higher conversion signifies a more efficient
catalyst. Conversely, for a specific conversion, a lower
temperature signifies a more efficient catalyst.
[0145] FIG. 19 shows the results for Type D/H catalyst with a
composition of 16%
Cu/Ce.sub.0.3Zr.sub.0.6Nd.sub.0.05Pr.sub.0.05O.sub.2. It should be
noted that a catalyst may fall into one or more types, such as
here, where the catalyst is both Type D and Type H. The light-off
test at R=1.05 shows that the catalyst has T.sub.50 for CO at
267.degree. C. and a T.sub.50 for HC at 525.degree. C. The maximum
conversion for NO is about 2% at 640.degree. C. Increasing the
R-value to 1.5 improves the NO conversion, but the CO and HC
performance deteriorates. The light-off test at R=1.5 shows that
the catalyst has T.sub.50s for CO and HC decrease to 323.degree. C.
and 595.degree. C., respectively. The NO light-off at R=1.5 shows a
T.sub.50 of 494.degree. C.
[0146] FIG. 20 shows the results for Type D/H catalyst with a
composition of 12% Cu/Ce.sub.0.6Zr.sub.0.3La.sub.0.1O.sub.2. It
should be noted that a catalyst may fall into one or more types,
such as here, where the catalyst is both Type D and Type H. The
light-off test at R=1.05 shows that the catalyst has T.sub.50 for
CO at 237.degree. C. and a T.sub.50 for HC at 543.degree. C. The
maximum conversion for NO is about 4% at 640.degree. C. Increasing
the R-value to 1.5 improves the NO conversion, but the CO and HC
performance deteriorates. The light-off test at R=1.5 shows that
the catalyst has T.sub.50s for CO and HC decrease to 329.degree. C.
and 611.degree. C., respectively. The NO light-off at R=1.5 shows a
T.sub.50 of 515.degree. C.
[0147] FIG. 21 shows the results for Type D/H catalyst with a
composition of 10% Cu+12% Ce/La--Al.sub.2O.sub.3. It should be
noted that a catalyst may fall into one or more types, such as
here, where the catalyst is both Type D and Type H. The light-off
test at R=1.05 shows that the catalyst has T.sub.50 for CO at
298.degree. C. and a T.sub.50 for HC at 546.degree. C. The maximum
conversion for NO is about 3% at 640.degree. C. Increasing the
R-value to 1.5 improves the NO conversion, but the CO and HC
performance deteriorates. The light-off test at R=1.5 shows that
the catalyst has T.sub.50s for CO and HC decrease to 325.degree. C.
and 598.degree. C., respectively. The NO light-off at R=1.5 shows a
T.sub.50 of 461.degree. C.
EXAMPLE 6
Light-Off Test for Type F ZPGM Transition Metal Catalysts
[0148] FIGS. 22-24 show the light-off test results for examples of
Type F catalyst. A light-off test was performed on aged
(800.degree. C. for 16 hours, composed of a 56 second rich segment
and a 4 second lean segment) catalysts of the present invention.
The test was performed by increasing the temperature from about
100.degree. C. to 640.degree. C. at R-value=1.05 and R-value=1.5.
The light-off test measures the conversions of nitrogen oxide,
carbon monoxide, and hydrocarbons as a function of the catalyst
system temperature. For a specific temperature, a higher conversion
signifies a more efficient catalyst. Conversely, for a specific
conversion, a lower temperature signifies a more efficient
catalyst.
[0149] FIG. 22 shows the results for Type F catalyst with a
composition of CuLa.sub.0.04Al.sub.1.96O.sub.4. The light-off test
at R=1.05 shows that the catalyst has T.sub.50 for CO at
334.degree. C. The maximum conversions for NO and HC at 640.degree.
C. are about 6% and 38%, respectively. Increasing the R-value to
1.5 improves the NO conversion, but the CO and HC performance
deteriorates. The light-off test at R=1.5 shows that the catalyst
has T.sub.50 for CO decreases to about 453.degree. C. The NO
light-off at R=1.5 shows a T.sub.50 of 521.degree. C. While, the
maximum conversion for HC is about 16% at 640.degree. C.
[0150] FIG. 23 shows the results for Type F catalyst with a
composition of Cu.sub.0.5Fe.sub.0.5La.sub.0.04Al.sub.1.96O.sub.4.
The light-off test at R=1.05 shows that the catalyst has T.sub.50
for CO at 346.degree. C. and a T.sub.50 for HC at 535.degree. C.
The maximum NO conversion is about 1% at 640.degree. C. Increasing
the R-value to 1.5 improves the NO conversion, but the CO and HC
performance deteriorates. The light-off test at R=1.5 shows that
the catalyst has T.sub.50s for CO and HC decrease to 368.degree. C.
and 588.degree. C., respectively. The NO light-off at R=1.5 shows a
T.sub.50 of 491.degree. C.
[0151] FIG. 24 shows the results for Type F catalyst with a
composition of CuLa.sub.0.04Al.sub.1.47Mn.sub.0.49O.sub.4. The
light-off test at R=1.05 shows that the catalyst has T.sub.50 for
CO at 371.degree. C. The maximum conversions for NO and HC at
640.degree. C. are about 2% and 27%, respectively. Increasing the
R-value to 1.5 improves the NO conversion, but the CO and HC
performance deteriorates. The light-off test at R=1.5 shows that
the catalyst has T.sub.50 for CO decreases to about 479.degree. C.
While, the maximum conversions for NO and HC are each about 16% at
640.degree. C.
EXAMPLE 7
Light-Off Test for Type G ZPGM Transition Metal Catalysts
[0152] FIGS. 25 -28 show the light-off test results for examples of
Type G/Type D catalyst. It should be noted that a catalyst may fall
into one or more types, such as here, where the catalyst is both
Type G and Type D. A light-off test was performed on aged
(800.degree. C. for 16 hours, composed of a 56 second rich segment
and a 4 second lean segment) catalysts of the present invention.
The test was performed by increasing the temperature from about
100.degree. C. to 640.degree. C. at R-value=1.05 and R-value=1.5.
The light-off test measures the conversions of nitrogen oxide,
carbon monoxide, and hydrocarbons as a function of the catalyst
system temperature. For a specific temperature, a higher conversion
signifies a more efficient catalyst. Conversely, for a specific
conversion, a lower temperature signifies a more efficient
catalyst.
[0153] FIG. 25 shows the results for Type G/Type D catalyst with a
composition of 10%
Ag/Cu.sub.0.5Fe.sub.0.5La.sub.0.04Al.sub.1.96O.sub.4. It should be
noted that a catalyst may fall into one or more types, such as
here, where the catalyst is both Type G and Type D. The light-off
test at R=1.05 shows that the catalyst has T.sub.50 for CO at
383.degree. C. The maximum conversions for NO and HC at 640.degree.
C. are about 1% and 33%, respectively. Increasing the R-value to
1.5 improves the NO conversion, but the CO and HC performance
deteriorates. The light-off test at R=1.5 shows that the catalyst
has T.sub.50 for CO decreases to about 394.degree. C. The NO
light-off at R=1.5 shows a T.sub.50 of 485.degree. C. While, the
maximum conversion for HC is about 16% at 640.degree. C.
[0154] FIG. 26 shows the results for Type G/Type D catalyst with a
composition of 10% Cu/CuLa.sub.0.04Al.sub.1.96O.sub.4. It should be
noted that a catalyst may fall into one or more types, such as
here, where the catalyst is both Type G and Type D. The light-off
test at R=1.05 shows that the catalyst has T.sub.50 for CO at
272.degree. C. and a T.sub.50 for HC at 464.degree. C. There is no
measured NO conversion up to 640.degree. C. Increasing the R-value
to 1.5 improves the NO conversion, but the CO and HC performance
deteriorates. The light-off test at R=1.5 shows that the catalyst
has T.sub.50s for CO and HC decrease to 375.degree. C. and
565.degree. C., respectively. The NO light-off at R=1.5 shows a
T.sub.50 of 500.degree. C.
[0155] FIG. 27 shows the results for Type G/Type D catalyst with a
composition of 20% CuO/MgLa.sub.0.04Al.sub.1.96O.sub.4. It should
be noted that a catalyst may fall into one or more types, such as
here, where the catalyst is both Type G and Type D. The light-off
test at R=1.05 shows that the catalyst has T.sub.50 for CO at
305.degree. C. and a T.sub.50 for HC at 513.degree. C. The maximum
NO conversion is about 1% at 640.degree. C. Increasing the R-value
to 1.5 improves the NO conversion, but the CO and HC performance
deteriorates. The light-off test at R=1.5 shows that the catalyst
has T.sub.50s for CO and HC decrease to 412.degree. C. and
587.degree. C., respectively. The NO light-off at R=1.5 shows a
T.sub.50 of 478.degree. C.
[0156] FIG. 28 shows the results for Type G/Type D catalyst with a
composition of 10% Cu+12% Ce/MgLa.sub.0.04Al.sub.1.96O.sub.4. It
should be noted that a catalyst may fall into one or more types,
such as here, where the catalyst is both Type G and Type D. The
light-off test at R=1.05 shows that the catalyst has T.sub.50 for
CO at 302.degree. C. and a T.sub.50 for HC at 506.degree. C. The
maximum NO conversion is about 2% at 640.degree. C. Increasing the
R-value to 1.5 improves the NO conversion, but the CO and HC
performance deteriorates. The light-off test at R=1.5 shows that
the catalyst has T.sub.50s for CO and HC decrease to 338.degree. C.
and 585.degree. C., respectively. The NO light-off at R=1.5 shows a
T.sub.50 of 461.degree. C.
EXAMPLE 8
Light-Off Test for Type D ZPGM Transition Metal Catalysts
[0157] FIG. 29 shows the light-off test results for an example of
Type D catalyst. A light-off test was performed on aged
(800.degree. C. for 16 hours, composed of a 56 second rich segment
and a 4 second lean segment) catalysts of the present invention.
The test was performed by increasing the temperature from about
100.degree. C. to 640.degree. C. at R-value=1.05 and R-value=1.5.
The light-off test measures the conversions of nitrogen oxide,
carbon monoxide, and hydrocarbons as a function of the catalyst
system temperature. For a specific temperature, a higher conversion
signifies a more efficient catalyst. Conversely, for a specific
conversion, a lower temperature signifies a more efficient
catalyst.
[0158] FIG. 29 shows the results for Type D catalyst with a
composition of 12%
CuO/(Ce.sub.0.6Zr.sub.0.3La.sub.0.1O.sub.2+MgLa.sub.0.04Al.sub.1.96O.-
sub.4 (40:60)). The light-off test at R=1.05 shows that the
catalyst has T.sub.50s for CO at 258.degree. C., for HC at
381.degree. C., and for NO at 519.degree. C. Increasing the R-value
to 1.5 improves the NO conversion, but the CO and HC performance
deteriorates. The light-off test at R=1.5 shows that the catalyst
has T.sub.50s for CO and HC decrease to 316.degree. C. and
464.degree. C., respectively. The NO light-off at R=1.5 shows a
T.sub.50 of 375.degree. C.
EXAMPLE 9
Light-Off Test for Type I Zeolite Catalyst
[0159] FIG. 30 shows the light-off test results for an example of
Type I Zeolite catalyst. A light-off test was performed on a fresh
catalyst of the present invention. The test was performed by
increasing the temperature from about 100.degree. C. to 640.degree.
C. at R-value=1.05. The light-off test measures the conversions of
nitrogen oxide, carbon monoxide, and hydrocarbons as a function of
the catalyst system temperature. For a specific temperature, a
higher conversion signifies a more efficient catalyst. Conversely,
for a specific conversion, a lower temperature signifies a more
efficient catalyst.
[0160] FIG. 30 shows the results for Type I catalyst with a
composition of 5% Ga+8% Cu/(ZSM-5). The light-off test at R=1.05
shows that the catalyst has T.sub.50s for CO at 376.degree. C., for
HC at 319.degree. C., and for NO at 343.degree. C.
EXAMPLE 10
Light-Off Test for Architecture Type 3, which Comprises a
Substrate, a Washcoat, and an Overcoat, wherein the Overcoat
Comprises at Least One Catalyst, but the Washcoat does not
[0161] FIG. 31 shows the light-off test results for an example of
Architecture Type 3 Catalyst, which comprises a substrate, a
washcoat, and an overcoat, wherein the overcoat comprises at least
one catalyst, but the washcoat does not (washcoat comprises
La--Al.sub.2O.sub.3+Ce.sub.0.6Zr.sub.0.3Nd.sub.0.05Pr.sub.0.05O.sub.2;
60:40; 100 g/L and overcoat comprises 12% Cu on
Ce.sub.0.6Zr.sub.0.3Nd.sub.0.05Pr.sub.0.05O.sub.2; 150 g/L). A
light-off test was performed on aged (800.degree. C. for 16 hours,
composed of a 56 second rich segment and a 4 second lean segment)
catalysts of the present invention. The test was performed by
increasing the temperature from about 100.degree. C. to 640.degree.
C. at R-value=1.05 and R-value=1.5. The light-off test measures the
conversions of nitrogen oxide, carbon monoxide, and hydrocarbons as
a function of the catalyst system temperature. For a specific
temperature, a higher conversion signifies a more efficient
catalyst. Conversely, for a specific conversion, a lower
temperature signifies a more efficient catalyst.
[0162] The light-off test at R=1.05 shows that the catalyst has
T.sub.50 for CO at 314.degree. C. and a T.sub.50 for HC at
464.degree. C. The maximum NO conversion is about 6% at 640.degree.
C. Increasing the R-value to 1.5 improves the NO conversion, but
the HC performance deteriorates. The light-off test at R=1.5 shows
that the catalyst has T.sub.50s for CO and HC decrease to
316.degree. C. and 566.degree. C., respectively. The NO light-off
at R=1.5 shows a T.sub.50 of 453.degree. C.
EXAMPLE 11
Light-Off Test for Catalyst Systems ZPGM-1 through ZPGM-6 (Fresh
and Aged)
[0163] FIGS. 32-37 show the light-off test results for ZPGM-1
through ZPGM-6. A light-off test was performed on fresh and aged
(1050.degree. C. for 10 hrs cycling between a 56 second rich
segment and a 4 second lean segment) catalysts of the present
invention. The test was performed by increasing the temperature
from about 100.degree. C. to 640.degree. C. at R-value=1.05. The
plotted temperatures in the figures were measured at the middle of
the catalyst. The light-off test measures the conversions of
nitrogen oxide, carbon monoxide, and hydrocarbons as a function of
the catalyst system temperature. For a specific temperature, a
higher conversion signifies a more efficient catalyst. Conversely,
for a specific conversion, a lower temperature signifies a more
efficient catalyst.
[0164] FIG. 32 shows the light-off results at R=1.05 for fresh and
aged ZPGM-1 catalyst system
(Ce.sub.0.6La.sub.0.4Mn.sub.0.6Cu.sub.0.4O.sub.3). The light-off
test for the fresh catalyst system shows that the CO and HC exhibit
T.sub.50s at 288.degree. C. and at 503.degree. C., respectively.
The maximum NO conversion is about 19% at 600.degree. C. After
aging, the catalyst performance decreases for CO, HC and NO. The
aged catalyst shows a T.sub.50 for CO at about 600.degree. C. The
maximum conversions for HC and NO are 19% and 2%, respectively, at
600.degree. C.
[0165] FIG. 33 shows the light-off results at R=1.05 for fresh and
aged ZPGM-2 catalyst system (8% Cu impregnated on
Al.sub.2O.sub.3+Ce.sub.0.64Zr.sub.0.21La.sub.0.15O.sub.2 (60:40
weight ratio of Al.sub.2O.sub.3 to
Ce.sub.0.64Zr.sub.0.21La.sub.0.15O.sub.2)). The light-off test for
the fresh catalyst system shows that the CO and HC exhibit
T.sub.50s at 205.degree. C. and at 389.degree. C., respectively.
The maximum NO conversion is about 22% at 600.degree. C. After
aging, the catalyst performance decreases for CO, HC and NO. The
maximum conversions for CO, HC and NO are 27%, 24% and 3%,
respectively, at 600.degree. C.
[0166] FIG. 34 shows the light-off results at R=1.05 for fresh and
aged ZPGM-3 catalyst system (8% Cu+6.1% Ce+2.4% Zr+1.5% La
impregnated on 15%
Sn--Al.sub.2O.sub.3+Ce.sub.0.6Zr.sub.0.3Nd.sub.0.05Pr.sub.0.05O.sub.2
(60:40 weight ratio of Sn--Al.sub.2O.sub.3 to
Ce.sub.0.6Zr.sub.0.3Nd.sub.0.05Pr.sub.0.05O.sub.2)). The light-off
test for the fresh catalyst system shows that the CO, HC and NO
exhibit T.sub.50s at 205.degree. C., at 389.degree. C., and
651.degree. C., respectively. After aging, the catalyst performance
decreases for CO, HC and NO. The aged catalyst shows a T.sub.50 for
CO and HC at about 599.degree. C. and 651.degree. C., respectively.
The maximum conversion for NO is 5% at 700.degree. C.
[0167] FIG. 35 shows the light-off results at R=1.05 for fresh and
aged ZPGM-4 catalyst system (overcoat containing 12% Cu impregnated
on Ce.sub.0.64Zr.sub.0.21La.sub.0.15O.sub.2+Al.sub.2O.sub.3 (60:40
weight ratio of Ce.sub.0.64Zr.sub.0.21La.sub.0.5O.sub.2 to
Al.sub.2O.sub.3) and a washcoat containing 8% Cu+6.1% Ce+2.4%
Zr+1.5% La impregnated impregnated on 15%
Sn--Al.sub.2O.sub.3+Ce.sub.0.6Zr.sub.0.3Nd.sub.0.05Pr.sub.0.05O.sub.2
(60:40 weight ratio of Sn--Al.sub.2O.sub.3 to
Ce.sub.0.6Zr.sub.0.3Nd.sub.0.05Pr.sub.0.05O.sub.2)). The light-off
test for the fresh catalyst system shows that the CO, HC and NO
exhibit T.sub.50s at 254.degree. C., at 442.degree. C., and
636.degree. C., respectively. After aging, the catalyst performance
decreases for CO, HC and NO. The aged catalyst shows a T.sub.50 for
CO and HC at about 462.degree. C. and 604.degree. C., respectively.
The maximum conversion for NO is about 30% at 770.degree. C.
[0168] FIG. 36 shows the light-off results at R=1.05 for fresh and
aged ZPGM-5 catalyst system (overcoat containing 12.4% CuO
impregnated on
La--Al.sub.2O.sub.3+Ce.sub.0.6Zr.sub.0.3Nd.sub.0.05Pr.sub.0.05O.sub.2
(25:75 weight ratio of La--Al.sub.2O.sub.3 to
Ce.sub.0.6Zr.sub.0.3Nd.sub.0.05Pr.sub.0.05O.sub.2) and a washcoat
containing 8% Cu+6.1% Ce+2.4% Zr+1.5% La impregnated on
La--Al.sub.2O.sub.3+Ce.sub.0.6Zr.sub.0.3Nd.sub.0.05Pr.sub.0.05O.sub.2
(60:40 weight ratio of La--Al.sub.2O.sub.3 to
Ce.sub.0.6Zr.sub.0.3Nd.sub.0.05Pr.sub.0.05O.sub.2)). The light-off
test for the fresh catalyst system shows that the CO, HC and NO
exhibit T.sub.50s at 262.degree. C., at 449.degree. C., and
608.degree. C., respectively. After aging, the catalyst performance
decreases for CO, HC and NO. The aged catalyst shows a T.sub.50 for
CO and HC at about 571.degree. C. and 654.degree. C., respectively.
The maximum conversion for NO is about 1% at 700.degree. C.
[0169] FIG. 37 shows the light-off results at R=1.05 for fresh and
aged ZPGM-6 catalyst system (overcoat containing 10% Cu+12% Ce
impregnated on MgAl.sub.2O.sub.4+16% Cu impregnated on
Ce.sub.0.6Zr.sub.0.3Nd.sub.0.05Pr.sub.0.05O.sub.2 (60:40 weight
ratio of Ce impregnated on MgAl.sub.2O.sub.4 to 16% Cu impregnated
on Ce.sub.0.6Zr.sub.0.3Nd.sub.0.05Pr.sub.0.05O.sub.2) (65 g/L) and
a washcoat containing 4% Cu+6.1% Ce+2.4% Zr+1.5% La impregnated on
MgAl.sub.2O.sub.4+Ce.sub.0.64Zr.sub.0.21La.sub.0.15O.sub.2 (60:40
weight ratio of MgAl.sub.2O.sub.4 to
Ce.sub.0.64Zr.sub.0.21La.sub.0.15O.sub.2)). The light-off test for
the fresh catalyst system shows that the CO, HC and NO exhibit
T.sub.50s at 262.degree. C., at 463.degree. C., and 622.degree. C.,
respectively. After aging, the catalyst performance decreases for
CO, HC and NO. The aged catalyst shows a T.sub.50 for CO and HC at
about 425.degree. C. and 613.degree. C., respectively. The maximum
conversion for NO is about 23% at 730.degree. C.
[0170] Although the present invention has been described in terms
of specific embodiments, changes and modifications can be made
without departing from the scope of the invention which is intended
to be defined only by the scope of the claims. All references cited
herein are hereby incorporated by reference in their entirety,
including any references cited therein.
* * * * *