Remarkable performance of selective catalytic reduction of NOx by ammonia over copper-exchanged SSZ-52 catalysts

Abstract

The low-temperature catalytic performance of Cu-ion-exchanged SSZ-52 catalysts (with different amounts of ion-exchanged Cu) for the selective catalytic reduction of NOx by NH3 (NH3-SCR) is investigated. The Cu-ion-exchanged SSZ-52 catalysts are prepared by a new method by using fumed silica as the silicon source. Among the synthesized Cux-SSZ-52 catalyst series, Cu2.4-SSZ-52 exhibits the highest NH3-SCR activity. In addition, the de-NOx performance of Cu2.4-SSZ-52 is superior to that of Cu2.4-SSZ-13. Moreover, the catalytic performance of Cu2.4-SSZ-52 reduces only slightly after hydrothermal aging at 750 °C. The microporous structure, redox ability, acidity properties as well as the location and nature of the Cu species and the reactant adsorption process of the support and Cux-SSZ-52 catalysts are investigated in detail. Overall, the findings show that the unique structure and cages of SSZ-52 are responsible for its excellent catalytic performance.