Mixed metal 8-ring small pore molecular sieve catalyst compositions, catalytic articles, systems, and methods

Patent metadata

Field	Value
Publication number	US-9486792-B2
Application number	US-201414563172-A
Country	US
Kind code	B2
Filing date	Dec 8, 2014
Priority date	Oct 19, 2012
Publication date	Nov 8, 2016
Grant date	Nov 8, 2016

Abstract

Described are compositions and catalytic articles comprising both a copper-promoted 8-ring small pore molecular sieve and an iron-promoted 8-ring small pore molecular sieve. The catalytic articles are useful in methods and systems to catalyze the reduction of nitrogen oxides in the presence of a reductant.

First claim

What is claimed is:

1. A selective catalytic reduction article comprising both a first 8-ring small pore aluminosilicate zeolite ion-exchanged with copper and a second 8-ring small pore aluminosilicate zeolite ion-exchanged with iron, the catalyst effective to catalyze the reduction of nitrogen oxides in the presence of a reductant.

2. The article of claim 1 , wherein the first and second 8-ring small pore aluminosilicate zeolites are selected from the group consisting of zeolites having a structure type selected from AEI, AFT, AFX, CHA, EAB, ERI, KFI, LEV, SAS, SAT, and SAV.

3. The article of claim 2 , wherein the first and second 8-ring small pore aluminosilicate zeolites have the CHA crystal structure.

4. The article of claim 3 , wherein the 8-ring small pore aluminosilicate zeolite is selected from the group consisting of SSZ-13, SSZ-62, natural chabazite, zeolite K-G, Linde D, Linde R, LZ-218, LZ-235, LZ-236, ZK-14, and ZYT-6.

5. The article of claim 3 , wherein the aluminosilicate zeolite has a silica to alumina ratio in the range of 20 and 50.

6. The article of claim 1 , wherein the first 8-ring small pore aluminosilicate zeolite ion-exchanged with copper further comprises a barium component.

7. The article of claim 1 , wherein the catalytic article comprises a washcoat comprising the first 8-ring small pore aluminosilicate zeolite ion-exchanged with copper and the second 8-ring small pore aluminosilicate zeolite ion-exchanged with iron disposed on a substrate.

8. The article of claim 7 , wherein the second 8-ring small pore aluminosilicate zeolite ion-exchanged with iron is on a front zone and the first 8-ring small pore aluminosilicate zeolite ion-exchanged with copper is on a rear zone.

9. The article of claim 7 , wherein the first 8-ring small pore aluminosilicate zeolite ion-exchanged with copper is on a front zone and the second 8-ring small pore aluminosilicate zeolite ion-exchanged with iron is on a rear zone.

10. The article of claim 7 , wherein the second 8-ring small pore aluminosilicate zeolite ion-exchanged with iron is coated on the substrate as a bottom coat and the first 8-ring small pore aluminosilicate zeolite ion-exchanged with copper is coated on top of the second 8-ring small pore aluminosilicate zeolite ion-exchanged with iron.

11. The article of claim 7 , wherein the first 8-ring small pore aluminosilicate zeolite ion-exchanged with copper is coated on the substrate as a bottom coat and the second 8-ring small pore aluminosilicate zeolite ion-exchanged with iron is coated on top of the first 8-ring small pore aluminosilicate zeolite ion-exchanged with copper.

12. The article of claim 1 , wherein first 8-ring small pore aluminosilicate zeolite ion-exchanged with copper and the second 8-ring small pore aluminosilicate zeolite ion-exchanged with iron are present in a ratio in the range of 1:1 to 10:1 by weight of the first 8-ring small pore aluminosilicate zeolite material to the second 8-ring small pore aluminosilicate zeolite.

13. The article of claim 1 , wherein the first 8-ring small pore aluminosilicate zeolite and second 8-ring small pore aluminosilicate zeolite each are selected from SSZ-13 and SSZ-62 and are present in a ratio in the range of 1:1 to 10:1 by weight of the copper-exchanged 8-ring small pore aluminosilicate zeolite to the iron-exchanged 8-ring small pore aluminosilicate zeolite.

14. The article of claim 13 , wherein the first 8-ring small pore aluminosilicate zeolite further comprises a barium component.

15. The article of claim 1 , wherein the catalyst is effective to catalyze the selective catalytic reduction of nitrogen oxides in the presence of a reductant at temperatures between 200° C. and 600° C.

16. A method for selectively reducing nitrogen oxides (NO x ), the method comprising contacting an exhaust gas stream containing NO x with the selective catalytic reduction catalytic article of claim 1 .

Assignees

• Basf Corp
• N E Chemcat Corp
• Heesung Catalysts Corp
• Heesung Cataysts Corp

Inventors

• Mohanan Jaya L
• Burk Patrick
• Breen Michael
• Slawski Barbara
• Nagata Makoto
• Banno Yasuyuki
• Kim Eunseok

Classifications

• B01J29/763

  CHA-type, e.g. Chabazite, LZ-218 · CPC title

• B01D2255/20738

  Iron · CPC title

• B01J37/0246

  Coatings comprising a zeolite · CPC title

• B01J29/83

  Aluminophosphates [APO compounds] · CPC title

• B01J29/70

  of types characterised by their specific structure not provided for in groups B01J29/08 - B01J29/65 · CPC title