Transition metal/zeolite SCR catalysts
AssigneeJohnson Matthey Public Limited Company
InventorsPaul Joseph Andersen, John Leonello Casci, Hai-Ying Chen, Jillian Elaine Collier, Joseph Michael Fedeyko, Rodney Kok Shin Foo, Raj Rao Rajaram
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Abstract
A method of converting nitrogen oxides in a gas to nitrogen by contacting the nitrogen oxides with a nitrogenous reducing agent in the presence of a zeolite catalyst containing at least one transition metal, wherein the zeolite is a small pore zeolite containing a maximum ring size of eight tetrahedral atoms, wherein the at least one transition metal is selected from the group consisting of Cr, Mn, Fe, Co, Ce, Ni, Cu, Zn, Ga, Mo, Ru, Rh, Pd, Ag, In, Sn, Re, Jr and Pt.
Claims13
A catalyst composition for treating exhaust gas comprising:
- a. a small pore first aluminosilicate molecular sieve having a silica-to-alumina ratio of about 8 to about 150, having a first framework selected from AEI, CHA, and AFX, and containing from 0.1 to 10 wt % of Cu, based on the total weight of the molecular sieve, and
- b. a second small pore aluminosilicate molecular sieve having a silica-to-alumina ratio of about 8 to about 150, having a second framework selected from AEI, CHA, and AFX, and containing from 0.1 to 10 wt % of Fe, based on the total weight of the molecular sieve,
- wherein the catalyst is effective to promote the reaction of NH3 with NOx to form nitrogen and water, selectively.
Dependencies are inferred from the claim text.