Abstract: The system and methods described provide for an Fe-SAPO-34 catalyst in an SCR catalyst for reducing nitrogen oxides (NOx) from vehicle engine exhausts. In one example, the catalyst is formed by incorporating iron during synthesis of the SAPO-34 zeolite, which allows iron to be incorporated into the zeolite crystal lattice structure and eliminates the post-synthesis ion-exchange step. The resulting Fe-SAPO-34 catalyst, which may be used in combination with or in addition to a Cu-CHA catalyst, exhibits good high temperature activity at temperatures above 550° C. and provides for a good thermal stability.