Elimination of NH3 by Interfacial Charge Transfer over the Ag/CeSnOx Tandem Catalyst

作者：Yan Zhang, Min Zhang, Yuchao Zang, Huijun Wang, Caixia Liu, Liehao Wei, Yuhe Wang, Lijun He, Weichao Wang, Ziyin Zhang, Rui Han, Na Ji, Chunfeng Song, Xuebin Lu, Degang Ma, Yanrong Sun, Qingling Liu · 发表于：ACS Catalysis · 年份：2023 · DOI：10.1021/acscatal.2c05226 · 被引用次数：95 · 研究领域：Catalytic Processes in Materials Science、Ammonia Synthesis and Nitrogen Reduction、Advanced Photocatalysis Techniques

Selective catalytic oxidation of NH 3 is the most promising method for removing low-concentration NH 3 . However, achieving high activity and N 2 selectivity remains a great challenge. A Ag/CeSnO x tandem catalyst with dual active centers was designed and synthesized, which couples the NH 3 over-oxidation on the noble metal active sites with NO x reduction on the support. The tandem catalyst exhibited excellent NH 3 selective catalytic oxidation (NH 3 –SCO) performance at 200–400 °C. Based on various characterization techniques and DFT calculations, it was identified that the silver species on the Ag/CeSnO x catalysts existed as AgO nanoparticles (AgO NPs), and the electrons on the support were more easily transferred to AgO NPs, which promoted the oxidation activity of AgO and the reduction performance of the CeSnO x support. The coupling between the AgO NPs and CeSnO x helped balance the NH 3 oxidation rate and the NO x reduction rate. In addition, the uniform adsorption of gaseous NH 3 on the oxidation and reduction sites was also demonstrated by theoretical calculations, which is a prerequisite for tandem catalysis. By in situ DRIFTS, we revealed that the NH 3 –SCO reaction over Ag/CeSnO x catalysts mainly follows the internal selective catalytic reduction mechanism. It was characterized by excessive oxidation of NH 3 to NO x on AgO NPs. At a temperature lower than 200 °C, NO x was reduced to N 2 by the adsorbed NH 3 on the AgO. When the temperature was higher than 200 °C...