The Zr-Cu-Ce/ZSM-5 catalysts prepared by the simultaneous ion-exchange showed high activity for NO decomposition in the presence of O2,the highest conversion of NO was up to 75%,indicating that the Ce and Zr addition can enhance the activity of catalysts.A new highly active site,which facilitates oxygen mobilization and desorption,could be formed in the sample due to the Ce and Zr addition.In addition,the Zr addition can significant...