Catalyst article for use in an emission treatment system

Patent metadata

Field	Value
Publication number	US-10799832-B2
Application number	US-201815935178-A
Country	US
Kind code	B2
Filing date	Mar 26, 2018
Priority date	Mar 30, 2017
Publication date	Oct 13, 2020
Grant date	Oct 13, 2020

Abstract

A catalyst article for treating a flow of a combustion exhaust gas comprises: a catalytically active substrate comprising one or more channels extending along an axial length thereof through which, in use, a combustion exhaust gas flows, the one or more channels having a first surface for contacting a flow of combustion exhaust gas; wherein the substrate is formed of an extruded vanadium-containing SCR catalyst material, wherein a first layer is provided on at least a portion of said first surface, wherein the first layer comprises an ammonia slip catalyst composition comprising one or more platinum group metals supported on titania, a silica-titania mixed oxide, a Ce—Zr mixed oxide, or a mixture thereof, and a second layer is provided on at least a portion of the first layer and comprises an SCR catalyst composition.

First claim

The invention claimed is:

1. A catalyst article for treating a flow of a combustion exhaust gas, the article comprising:
a catalytically active substrate comprising one or more channels extending along an axial length thereof through which, in use, a combustion exhaust gas flows, the one or more channels having a first surface for contacting a flow of combustion exhaust gas;
wherein the substrate is formed of an extruded vanadium-containing SCR catalyst material,
wherein a first layer is provided on at least a portion of said first surface, wherein the first layer comprises an ammonia slip catalyst composition comprising one or more platinum group metals supported on titania, a silica-titania mixed oxide, a Ce—Zr mixed oxide, or a mixture thereof, and
a second layer is provided on at least a portion of the first layer and comprises an SCR catalyst composition.

2. The catalyst article according to claim 1 , wherein the substrate is a honeycomb flow-through monolith substrate.

3. The catalyst article according to claim 1 , wherein the substrate comprises from 1 to 3 wt % vanadium oxide.

4. The catalyst article according to claim 1 , wherein the first layer comprises from 0.05 to 0.5 wt % of the platinum group metal.

5. The catalyst article according to claim 1 , wherein the platinum group metal is Pt.

6. The catalyst article according to claim 1 , wherein the first layer covers up to 50% of the axial length of the substrate, and extends from an end of the article.

7. The catalyst article according to claim 1 , wherein the first layer covers at least 50% of the axial length of the substrate.

8. The catalyst article according to claim 1 , wherein the SCR catalyst composition of the second layer comprises a copper-promoted zeolite, an iron-promoted zeolite or a combination thereof.

9. The catalyst article according to claim 1 , wherein the second layer has an ammonia storage capacity of up to 0.1 g per g of the second layer when measured at 200° C.

10. The catalyst article according to claim 1 , wherein the second layer covers 100% of the first layer by area.

11. An emission treatment system for treating a flow of a combustion exhaust gas, the system comprising a source of combustion exhaust gas in fluid communication with the catalyst article of claim 1 , and a source of nitrogenous reductant arranged upstream of said article.

12. The emission treatment system according to claim 11 , wherein the first layer covers up to 50% of the axial length of the substrate and is provided extending from a downstream end of the article.

13. The emission treatment system according to claim 11 , wherein the source of combustion exhaust gas is a diesel engine.

14. A method for treating a flow of a combustion exhaust gas, the method comprising: contacting a flow of combustion exhaust gas with the catalyst article according to claim 1 in the presence of a nitrogenous reductant.

Assignees

• Johnson Matthey Plc

Inventors

• Howells Heledd
• Micallef David
• Newman Andrew
• Greenham Neil

Classifications

• B01J35/57

  Honeycombs · CPC title

• B01D2251/2062

  Ammonia · CPC title

• B01D2255/9032

  Two zones · CPC title

• B01D2255/407

  Zr-Ce mixed oxides · CPC title

• F01N3/2842

  specially adapted for monolithic supports, e.g. of honeycomb type (F01N3/2853 - F01N3/2871 take precedence) · CPC title