Promotion Effect of Iron on Activity and N-2 Selectivity of Mn/Ce Catalysts in the NH3-SCR Reaction

Manganese oxides are known to have good low-temperatureSCR performance,whereas improving their medium- and high-temperature catalytic performanceand N-2 selectivity remain a challenge. Herein, manganese-basedternary catalysts Fe-Mn/Ce, using CeO2 as the carrierand Fe as the second active component, were constructed to effectivelysolve this problem. Fe-Mn/Ce catalysts show excellent catalyticperformance, with NO x conversions of morethan 90% over a wide operating temperature range (164.5-419.4 degrees C) with high and N-2 selectivity. Further investigationshowed that, for the Fe-Mn/Ce catalyst with rich redox sitesand surface acidity, higher amounts of Fe2+ and Mn4+ are the important factors promoting excellent SCR reactivity.Besides, the Fe modification can generate effective electron transferto reduce the N2O generation pathway and increase the catalyticreaction sites, thus enhancing the overall catalytic performance.