Catalytic activity and mechanism of selective catalytic oxidation of ammonia by Ag-CeO2 under different preparation conditions.

Abstract

Given the problem of the high-temperature window of CeO2 catalyst activity, this study evaluated the catalytic properties of Ag/CeO2 prepared by changing the preparation methods and loadings. Our experiments showed that Ag/CeO2-IM catalysts prepared by the equal volume impregnation method could have better activity at lower temperatures. The Ag/CeO2-IM catalyst achieves 90% NH3 conversion at 200 °C, and the main reason is that the Ag/CeO2-IM catalyst has more vital redox properties, and the NH3 catalytic oxidation temperature is lower. However, its high-temperature N2 selectivity still needs to be improved and may be related to the less acidic sites on the catalyst surface. On both catalyst surfaces, the i-SCR mechanism governs the NH3-SCO reaction.