Transition metal/zeolite scr catalysts

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, Ir and Pt.

1 . An exhaust system for treatment of an exhaust gas stream comprising NO x  and particulate matter, comprising:
 an SCR catalyst substrate containing a catalyst comprising Cu-SAPO-34; and   a nitrogenous reductant injector positioned upstream of the SCR catalyst substrate,   
       wherein the catalyst is effective to promote the reaction of the reductant with nitrogen oxides to form nitrogen and H 2 O selectively.