Excellent Activity and Selectivity of One-Pot Synthesized Cu–SSZ-13 Catalyst in the Selective Catalytic Oxidation of Ammonia to Nitrogen

Abstract

One-pot synthesized Cu-SSZ-13 catalyst treated with dilute HNO₃ achieved superior activity and selectivity in the selective catalytic oxidation (SCO) of NH₃ to nitrogen, in comparison with other zeolite-based catalysts and most of metal-oxide catalysts. Furthermore, the catalyst showed the similar or even higher catalytic activity than the partial noble-metal catalysts, and meanwhile its N₂ selectivity was superior to most noble-metal catalysts. The characterization results demonstrated that more Cu²⁺ ions existing in Cu-SSZ-13 catalyst were advantageous to its NH₃-SCO activity. The in situ DRIFTS results indicated that the reactivity of NH₃ species adsorbed on Lewis and Brønsted acid sites over Cu-SSZ-13-O-H catalyst depended on the reaction temperature. The results of this study suggest the one-pot synthesized Cu-SSZ-13 is a promising NH₃-SCO catalyst for practical application, either mobile or stationary pollution sources.