Promotion Effect of Iron on Activity and N2 Selectivity of Mn/Ce Catalysts in the NH3-SCR Reaction

Abstract

Manganese oxides are known to have good low-temperature SCR performance, whereas improving their medium- and high-temperature catalytic performance and N2 selectivity remain a challenge. Herein, manganese-based ternary catalysts Fe–Mn/Ce, using CeO2 as the carrier and Fe as the second active component, were constructed to effectively solve this problem. Fe–Mn/Ce catalysts show excellent catalytic performance, with NOx conversions of more than 90% over a wide operating temperature range (164.5–419.4 °C) with high and N2 selectivity. Further investigation showed that, for the Fe–Mn/Ce catalyst with rich redox sites and surface acidity, higher amounts of Fe2+ and Mn4+ are the important factors promoting excellent SCR reactivity. Besides, the Fe modification can generate effective electron transfer to reduce the N2O generation pathway and increase the catalytic reaction sites, thus enhancing the overall catalytic performance.