Catalyst for treating exhaust gas
View Patent ↗Provided is a catalyst composition having an aluminosilicate molecular sieve having an AEI structure and a mole ratio of silica-to-alumina of about 20 to about 30 loaded with about 1 to about 5 weight percent of a promoter metal, based on the total weight of the molecular sieve material. Also provided are method, articles, and systems utilizing the catalyst composition.
1. A catalytic article comprising:
a. a catalyst composition comprising an aluminosilicate molecular sieve having an AEI structure, a mean crystal size of about 0.1 to about 15 μm, and being substantially free of halogens, and about 1 to about 5 weight percent of a promoter metal, based on the total weight of the molecular sieve material, and a binder comprising a component selected from alumina, silica, non-zeolite silica alumina, titania, zirconia, and ceria; and
b. a particulate filter upon and/or within which the catalyst composition is disposed.
2. The catalytic article of claim 1 , wherein the binder comprises alumina.
3. The catalytic article of claim 2 , wherein the metal is selected from copper and iron.
4. The catalytic article of claim 2 , wherein the alumina is gamma alumina and/or theta alumina.
5. The catalytic article of claim 2 , wherein the binder consisting essentially of alumina.
6. The catalytic article of claim 2 , wherein the filter is a wall-flow filter.
7. The catalytic article of claim 6 , wherein the catalyst composition is a coating on or within the filter.
8. The catalytic article of claim 7 , wherein the coating comprises a surface coating on the filter, a coating permeates the surface of the filter, or a combination thereof.
9. The catalytic article of claim 8 , wherein the coating comprises a surface coating on the filter.
10. The catalytic article of claim 9 , wherein the coating is on the inlet side of the filter.
11. The catalytic article of claim 10 , wherein the filter further comprises an ammonia oxidation catalyst disposed on the outlet side of the filter.
12. The catalytic article of claim 2 , wherein the filter has a porosity of about 40-70%.
13. The catalytic article of claim 2 , wherein the filter has an efficiency of at least about 70%.
14. The catalytic article of claim 2 , wherein the filter has a pore interconnectivity volume of at least about 30%.
15. The catalytic article of claim 2 , wherein the filter has a mean pore size of about 10 to about 40 μm.
16. The catalytic article of claim 2 , wherein the catalyst composition is a washcoat, and the washcoat is present on the filter at a concentration of about 1.5 to 2.5 g/in 3 .
17. The catalytic article of claim 1 , wherein said molecular sieve having an AEI framework has a SAR of about 15 to about 25 , a mean crystal size of about 0.1 to about 10 μm.
18. The catalytic article of claim 17 , wherein said mean crystal size is about 0.5 to 5 μm.