NOx adsorber catalyst

Patent metadata

Field	Value
Publication number	US-11117097-B2
Application number	US-201715724424-A
Country	US
Kind code	B2
Filing date	Oct 4, 2017
Priority date	Oct 4, 2016
Publication date	Sep 14, 2021
Grant date	Sep 14, 2021

Abstract

A NO x adsorber catalyst composition, a NO x adsorber catalyst and its use in an emission treatment system for internal combustion engines, is disclosed. The NO x adsorber catalyst composition a support material and one or more platinum group metals disposed on the support material, wherein the support material comprises a NO x storage enhancer.

First claim

The invention claimed is:

1. A NO x adsorber catalyst composition comprising a metal or ceramic substrate, a first layer, and a second layer, wherein said first layer comprises a support material and one or more platinum group metals disposed on the support material;
wherein the support material is doped with a NO x storage enhancer;
wherein the one or more platinum group metals is a mixture or alloy of platinum and palladium;
wherein the NO x storage enhancer is selected from the group consisting of scandium, yttrium, promethium, europium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, strontium, or metal oxides thereof; and
wherein the second layer comprises a platinum group metal (PGM).

2. The NO x adsorber catalyst composition of claim 1 , wherein the NO x storage enhancer is holmium, or metal oxides thereof.

3. The NO x adsorber catalyst composition of claim 1 , wherein the support material is selected from the group consisting of cerium oxide, a ceria-zirconia mixed oxide, a ceria-magnesia-alumina mixed oxide, and an alumina-ceria-zirconia mixed oxide.

4. The NOx adsorber catalyst composition according to claim 3 , wherein the support material is cerium oxide.

5. The NO x adsorber catalyst composition of claim 1 , the first layer comprises barium.

6. The NO x adsorber catalyst composition of claim 1 , wherein the NO x adsorber catalyst composition is substantially free of barium.

7. The NO x adsorber catalyst of claim 1 , wherein the metal or ceramic substrate is a flow-through monolith or a filter monolith.

8. An emission treatment system for treating a flow of a combustion exhaust gas comprising an internal combustion engine and the NO x adsorber catalyst of claim 1 .

9. The emission treatment system of claim 8 , wherein the internal combustion engine is a diesel engine.

10. The emission treatment system of claim 8 , further comprising a selective catalytic reduction catalyst system, a particulate filter, a selective catalytic reduction filter system, a passive NO x adsorber, a three-way catalyst system, or combinations thereof.

11. A method for treating an exhaust gas from an internal combustion engine comprising contacting the exhaust gas with the NO x adsorber catalyst of claim 1 .

12. The method of claim 11 , wherein the exhaust gas is at a temperature of about 100 to 300° C.

13. The method of claim 11 , wherein the NO x adsorber catalyst has a higher NO x storage capacity relative to an equivalent support material that does not contain the NO x storage enhancer.

14. The method of claim 11 further comprising a rich purge step, wherein the NO x adsorber catalyst has a higher NO x reduction activity during the rich purge relative to an equivalent support material that does not contain the NO x storage enhancer.

15. The method of claim 11 further comprising a rich purge step, wherein the NO x adsorber catalyst has a higher N 2 selectivity relative to an equivalent support material that does not contain the NO x storage enhancer.

16. The NO x adsorber catalyst of claim 1 , wherein the NO x storage enhancer is present in an amount of about 0.5-20 mol. %, expressed as a total mol % of all of the components of the NO x storage enhancer.

17. The NO x adsorber catalyst of claim 1 , wherein the one or more platinum group metals is present in an amount of 0.5-5 weight %.

Assignees

• Johnson Matthey Plc

Inventors

• Martin Desiree Duran
• Rajaram Raj

Classifications

• Y02C20/10

  of nitrous oxide (N2O) · CPC title

• B01J23/44

  Palladium · CPC title

• B01J23/42

  Platinum · CPC title

• B01D53/9427

  for removing nitrous oxide · CPC title

• C01F17/235

  Cerium oxides or hydroxides · CPC title