Excellent activity and selectivity of Cu-SSZ-13 in the selective catalytic reduction of NO_x with NH_3

摘要

Superior activity and selectivity of a Cu ion-exchanged SSZ-13 zeolite in the selective catalytic reduction (SCR) of NO_x with NH_3 were observed, in comparison with Cu-beta and Cu-ZSM-5 zeolites. Cu-SSZ-13 was not only more active in the NO_x SCR reaction over the entire temperature range studied (up to 550 °C), but also more selective toward nitrogen formation, resulting in significantly lower amounts of NO_x by-products (i.e., NO_2 and N_2O) than the other two zeolites. In addition, Cu-SSZ-13 demonstrated the highest activity and N _2 formation selectivity in the oxidation of NH_3. The results of this study strongly suggest that Cu-SSZ-13 is a promising candidate as a catalyst for NO_x SCR with great potential in after-treatment systems for either mobile or stationary sources.