Layered exhaust treatment catalyst
First Claim
1. A layered exhaust treatment catalyst comprising(a) a carrier;
- (b) a bottom layer deposited on the carrier, said bottom layer consisting essentially of an oxygen storage component supported on a refractory metal oxide;
(c) a first layer deposited on the bottom layer, said first layer comprising a palladium metal component, a platinum metal component and an oxygen storage component supported on a refractory metal oxide, the ratio of the palladium metal component to the platinum metal component being in the range of about 5;
1 to about 200;
1; and
(d) a second layer deposited on the first layer comprising a rhodium metal component, a platinum metal component and an oxygen storage component supported on a refractory metal oxide, the ratio of the rhodium metal component to the platinum metal component being in the range of about 5;
1 to about 30;
1,wherein the oxygen storage component in the bottom layer, first layer and second layer is independently selected from the group consisting of ceria, lanthania, praseodymia, a ceria-praseodymia composite, a ceria-praseodymia-zirconia composite, a ceria-praseodymia-zirconia-neodymia composite and a ceria-lanthania-praseodymia-zirconia-neodymia composite.
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Accused Products
Abstract
A layered exhaust treatment catalyst comprising: (a) a carrier such as cordierite; (b) a first layer deposited on the carrier comprising a palladium metal component, a platinum metal component and an oxygen storage component such as ceria supported on a refractory metal oxide such as gamma-alumina; and (c) a second layer deposited on the first layer comprising a rhodium metal component, a platinum metal component and an oxygen storage component such as ceria supported on a refractory metal oxide such as gamma-alumina. Preferably, the catalyst also includes a bottom layer interposed between the carrier and the first layer. The bottom layer comprises an oxygen storage component such as ceria supported on a refractory metal oxide such as gamma-alumina. The amount of the oxygen storage component of the catalyst may be “tuned”, i.e., adjusted, to meet the needs of a vehicle'"'"'s on-board diagnostic (“OBD”) catalyst efficiency monitoring system, without adversely affecting the performance of the catalyst.
98 Citations
10 Claims
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1. A layered exhaust treatment catalyst comprising
(a) a carrier; -
(b) a bottom layer deposited on the carrier, said bottom layer consisting essentially of an oxygen storage component supported on a refractory metal oxide; (c) a first layer deposited on the bottom layer, said first layer comprising a palladium metal component, a platinum metal component and an oxygen storage component supported on a refractory metal oxide, the ratio of the palladium metal component to the platinum metal component being in the range of about 5;
1 to about 200;
1; and(d) a second layer deposited on the first layer comprising a rhodium metal component, a platinum metal component and an oxygen storage component supported on a refractory metal oxide, the ratio of the rhodium metal component to the platinum metal component being in the range of about 5;
1 to about 30;
1,wherein the oxygen storage component in the bottom layer, first layer and second layer is independently selected from the group consisting of ceria, lanthania, praseodymia, a ceria-praseodymia composite, a ceria-praseodymia-zirconia composite, a ceria-praseodymia-zirconia-neodymia composite and a ceria-lanthania-praseodymia-zirconia-neodymia composite. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A layered exhaust treatment catalyst comprising:
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(a) a carrier; (b) a bottom layer disposed on the carrier, said bottom layer consisting essentially of an oxygen storage component supported on a refractory metal oxide; (c) a first layer disposed on the bottom layer, said first layer comprising a palladium metal component, a platinum metal component and an oxygen storage component supported on a refractory metal oxide, the ratio of the palladium metal component to the platinum metal component being in the range of about 5;
1 to about 20;
1 and(d) a second layer disposed on the first layer comprising a rhodium metal component, a platinum metal component and an oxygen storage component supported on a refractory metal oxide, the ratio of the rhodium metal component to the platinum metal component being in the range of about 5;
1 to about 20;
1. - View Dependent Claims (10)
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Specification