Effect of Ce and Zr modification on the performance of Cu/ZSM-5 catalysts in direct decomposition of NO

Cu/ZSM-5 catalysts were modified by adding Ce and Zr components and then characterized by O₂-TPD and TG analysis. The effect of ion-exchange sequence, Ce/Zr mol ratio and reaction conditions on the catalytic performance of Ce and Zr modified Cu/ZSM-5 were investigated. The results indicated that Cu species is essential in Zr-Cu-Ce/ZSM-5 catalyst as the active sites for NO decomposition, while the modification with Ce and Zr components can significantly enhance its catalytic performance for direct decomposition of NO in the presence of oxygen and reduce the reaction temperature required for achieving the maximum conversion of NO. The Zr-Cu-Ce/ZSM-5 catalyst modified by simultaneous Ce and Zr ion-exchange with Ce/Zr mol ratio of 1 exhibits thehighest performance for NO decomposition.