Aging-resistant catalyst article for internal combustion engines

Patent metadata

Field	Value
Publication number	US-10773209-B2
Application number	US-70674210-A
Country	US
Kind code	B2
Filing date	Feb 17, 2010
Priority date	Feb 20, 2009
Publication date	Sep 15, 2020
Grant date	Sep 15, 2020

Abstract

Catalyst articles comprising palladium and related methods of preparation and use are disclosed. Disclosed is a catalyst article comprising a first catalytic layer formed on a substrate, wherein the first catalytic layer comprises palladium impregnated on a ceria-free oxygen storage component and platinum impregnated on a refractory metal oxide, and a second catalytic layer formed on the first catalytic layer comprising platinum impregnated on an oxygen storage component and rhodium impregnated on a zirconia-coated or yttria-coated alumina. The palladium component of the catalyst article is present in a higher proportion relative to the other platinum group metal components. The catalyst articles provide improved reductions in NOx in exhaust gases, particularly after lean-rich aging.

First claim

What is claimed is:

1. A catalyst article for use in an internal combustion engine comprising:
a first catalytic layer formed on a substrate, wherein the first catalytic layer consists of palladium impregnated on a zirconia-rare earth metal composite containing from about 1-40% by weight of a rare earth metal selected from the group consisting of praseodymia, lanthana, neodymia, yttria, and combinations thereof;
platinum and optionally palladium, impregnated on alumina; and
a second catalytic layer formed on the first catalytic layer, the second catalytic layer comprising platinum impregnated on an oxygen storage component and rhodium impregnated on zirconia-coated or yttria-coated alumina, wherein the second catalytic layer does not contain palladium, wherein the catalyst article is effective to reduce nitrogen oxides in exhaust gas from the internal combustion engine, and
wherein the palladium content of the article is from 10 to 30-fold higher than the total platinum and rhodium content.

2. The article of claim 1 further comprising an etch coat layer on the substrate, wherein the etch coat layer underlies the first catalytic layer.

3. The article of claim 2 wherein the etch coat layer comprises a high surface area refractory metal oxide.

4. The article of claim 1 wherein the oxygen storage component of the second catalytic layer is a ceria-containing oxygen storage component.

5. A method of treating engine exhaust comprising hydrocarbons, carbon monoxide and nitrogen oxides comprising:
contacting the exhaust with a catalyst article of claim 1 ,
wherein the method is effective to reduce nitrogen oxides in the exhaust.

6. The method of claim 5 wherein the catalyst article further comprises an etch coat layer on the substrate, wherein the etch coat layer underlies the first catalytic layer.

7. The method of claim 5 wherein the exhaust is contacted with a catalyst article comprising a) palladium impregnated on praseodymia-doped zirconia and platinum impregnated on alumina in the first catalytic layer, and b) platinum impregnated on ceria-zirconia and rhodium impregnated on zirconia-coated alumina in the second layer.

8. The method of claim 7 wherein the ratio of platinum/palladium/rhodium is 0.5-10/1-80/0.5-10 by weight, respectively.

9. The method of claim 8 wherein the exhaust is contacted with a catalyst article comprising a total of 30-100 g/ft 3 of platinum group metal.

10. The method of claim 9 wherein the exhaust is contacted with a catalyst article comprising 1-90 g/ft 3 platinum, 1-90 g/ft 3 palladium and 1-30 g/ft 3 rhodium.

Assignees

• Liu Xinsheng
• Liu Ye
• Tran Pascaline Harrison
• Galligan Michael P
• Lin Wenyong
• Alive Keshavaraja
• Basf Corp

Inventors

• Liu Xinsheng
• Liu Ye
• Tran Pascaline Harrison
• Galligan Michael P
• Lin Wenyong
• Alive Keshavaraja

Classifications

• B01D2255/20715

  Zirconium · CPC title

• B01D2255/206

  Rare earth metals · CPC title

• B01D2255/1025

  Rhodium · CPC title

• B01D2255/1023

  Palladium · CPC title

• B01J35/57

  Honeycombs · CPC title