Highly active and thermally stable coated gasoline particulate filters

Patent metadata

Field	Value
Publication number	US-10265684-B2
Application number	US-201715586394-A
Country	US
Kind code	B2
Filing date	May 4, 2017
Priority date	May 4, 2017
Publication date	Apr 23, 2019
Grant date	Apr 23, 2019

Abstract

Coated gasoline particulate filters (cGPFs) that are produced according to varied material compositions and catalyst configurations are disclosed. The cGPFs include Fe—Ce (rich)-activated Rh compositions that provide greater catalytic functionality. These cGPFs are incorporated within engine systems as components of TWC systems for controlling and reducing engine exhaust emissions. The conversion performance of these TWC systems is assessed and compared employing worldwide harmonized light duty test cycle (WLTC) protocol within a gasoline fueled internal combustion engine. These TWC systems exhibit a significant catalytic performance when compared with the catalytic performance of a PGM-based Original Equipment Manufacturer (OEM) catalyst employed in TWC applications. Further, TWC catalysts are produced including Fe-activated Rh layers comprising dopant elements. The catalytic performance of the TWC catalysts is evaluated by performing light-off and standard isothermal oxygen storage capacity oscillating tests. The TWC catalysts exhibit improved catalytic performance and significant oxygen storage capacity.

First claim

What is claimed is:

1. A coated gasoline particulate filter comprising:
a substrate,
a catalytic layer deposited onto the substrate, the catalytic layer comprising
(i) a composition comprising a platinum group metal, iron, and cerium; or
(ii) a composition comprising a doped iron-rhodium oxide.

2. The particulate filter of claim 1 , wherein the catalytic layer comprises a platinum group metal, iron, and cerium, and the platinum group metal is rhodium.

3. The particulate filter of claim 2 , wherein a loading of the rhodium is from about 1 to 100 g/ft 3 , a loading of the iron is from about 200 to 1,680 g/ft 3 , and a loading of the cerium is about 200 to 4,200 g/ft 3 .

4. The particulate filter of claim 2 , wherein the catalytic layer further comprises one or more of nickel and a lanthanide selected from the group consisting of yttrium, lanthanum, praseodymium, and neodymium.

5. The particulate filter of claim 1 , wherein the catalytic layer comprises a doped iron-rhodium oxide having a formula A a Rh b Fe c Ox with a loading from about 400 to 9,600 g/ft 3 .

6. The particulate filter of claim 5 , wherein a is a value from about 0 to 0.3 mole fraction, b is greater than or equal to about 0.0004 mole fraction, and c is from about 0.69 to about 0.9996 mole fraction.

7. The particulate filter of claim 5 , wherein A is selected from the group consisting of zinc, nickel, cobalt, manganese, magnesium, calcium, strontium, yttrium, cerium, lanthanum, praseodymium, neodymium, terbium, ytterbium, gallium, barium, and combinations thereof.

8. The particulate filter of claim 1 , wherein the substrate comprises a cordierite wall-flow filter.

9. The particulate filter of claim 1 , wherein the substrate comprises a cordierite flow-through monolith.

10. The particulate filter of claim 1 , wherein the catalytic layer is deposited onto the substrate by a method selected from the group consisting of co-milling, co-precipitation, nitrate combustion, impregnation, sol-gel, and incipient wetness.

11. The particulate filter of claim 10 , wherein the catalytic layer is deposited onto the substrate by an impregnation method.

12. The particulate filter of claim 1 , wherein the particulate filter exhibits an increase in back-pressure less than about 5% in comparison to an identical blank filter substrate.

13. A catalytic system for treating an exhaust stream of a combustion engine comprising:
a combustion engine;
a close-coupled catalytic converter configured and arranged to accept at least on exhaust stream from said combustion engine, the close-coupled catalytic converter comprising a platinum group metal catalyst; and
a coated gasoline particulate filter downstream of, and in fluid communication with said close-coupled catalytic converter, the particulate filter comprising a substrate onto which a catalytic layer is deposited, the catalytic layer comprising
(i) a composition comprising a platinum group metal, iron, and cerium; or
(ii) a composition comprising a doped iron-rhodium oxide; and

wherein the catalytic system exhibits a comparable reduction in tailpipe emissions of NO X , CO, THC, and NMHC in comparison to a similar system having an underfloor catalytic converter comprising a platinum group metal catalyst as a downstream converter.

14. The catalytic system of claim 13 , wherein the catalytic layer comprises a composition comprising rhodium, iron, and cerium.

15. The catalytic system of claim 14 , wherein a loading of the rhodium is from about 1 to 100 g/ft 3 , a loading of the iron is from about 200 to 1,680 g/ft 3 , and a loading of the cerium is about 200 to 4,200 g/ft 3 .

16. The catalytic system of claim 14 , wherein the catalytic layer further comprises one or more of nickel and a lanthanide selected from the group consisting of yttrium, lanthanum, praseodymium, and neodymium.

17. The catalytic system of claim 13 , wherein the catalytic layer comprises a doped iron-rhodium oxide system having the formula A a Rh b Fe c Ox with a loading from about 400 to 9,600 g/ft 3 .

18. The catalytic system of claim 17 , wherein a is a value from about 0 to 0.3 mole fraction, b is greater than or equal to about 0.0004 mole fraction, and c is from about 0.69 to about 0.9996 mole fraction.

19. The catalytic system of claim 17 , wherein A is selected from the group consisting of zinc, nickel, cobalt, manganese, magnesium, calcium, strontium, yttrium, cerium, lanthanum, praseodymium, neodymium, terbium, ytterbium, gallium, barium, and combinations thereof.

20. A catalytic system for treating an exhaust stream of a combustion engine comprising:
a combustion engine;
a coated gasoline particulate filter configured and arranged to accept at least on exhaust stream from said combustion engine, the coated gasoline particulate filter comprising a substrate onto which a catalytic layer is deposited, the catalytic layer comprising
(i) a composition comprising a platinum group metal, iron, and cerium; or
(ii) a composition comprising a doped iron-rhodium oxide system.

21. A catalyst comprising
a cordierite flow-through monolith substrate;
a catalytic layer deposited onto the substrate, the catalytic layer comprising a doped iron-rhodium oxide catalyst composition having the formula A a Rh b Fe c Ox, wherein a is a value from about 0 to 0.3 mole fraction, b is greater than or equal to about 0.0004 mole fraction, and c is from about 0.69 to about 0.9996 mole fraction, and A is selected from the group consisting of zinc, nickel, cobalt, manganese, magnesium, calcium, strontium, yttrium, cerium, lanthanum, praseodymium, neodymium, terbium, ytterbium, gallium, and barium, and wherein the loading of the catalyst composition on the substrate is from about 5 to 120 moles/ft 3 , and the catalyst exhibits T 50 conversion temperatures for NOx and CO less than 245° C., and a T 50 conversion temperatures for THC less than 262° C.

22. The catalyst of claim 21 , wherein the catalyst exhibits an O 2 delay time that is between about 26 and 31 seconds.

23. The catalyst of claim 21 , wherein a is a value from about 0.01 to 0.3 mole fraction, and wherein b is a value from about 0.002 to 0.01 mole fraction.

24. The catalyst of claim 21 , wherein a is a value from about 0.05 to 0.2 mole fraction.

25. The catalyst of claim 21 , wherein A is nickel, lanthanum, or a combination thereof.

Assignees

• Clean Diesel Tech Inc
• Cdti Advanced Mat Inc

Inventors

• Hatfield Randal L

Classifications

• F01N3/0222

  the structure being monolithic, e.g. honeycombs · CPC title

• B01D2255/908

  O2-storage component incorporated in the catalyst · CPC title

• F01N3/035 Primary

  with catalytic reactors · CPC title

• B01J35/0006

  Operations & Transport · mapped topic

• B01J23/894 Primary

  with rare earths or actinides · CPC title