Promotion Effect of Iron on Activity and N<sub>2</sub> Selectivity of Mn/Ce Catalysts in the NH<sub>3</sub>-SCR Reaction
Zihan Gao, Runnong Yang, Zhaoying Wang, Wuyuan Liu, Ming Sun, Cheng Zhang, Lin Yu
Abstract
Manganese oxides are known to have good low-temperature SCR performance, whereas improving their medium- and high-temperature catalytic performance and N 2 selectivity remain a challenge. Herein, manganese-based ternary catalysts Fe–Mn/Ce, using CeO 2 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 NO x conversions of more than 90% over a wide operating temperature range (164.5–419.4 °C) with high and N 2 selectivity. Further investigation showed that, for the Fe–Mn/Ce catalyst with rich redox sites and surface acidity, higher amounts of Fe 2+ and Mn 4+ are the important factors promoting excellent SCR reactivity. Besides, the Fe modification can generate effective electron transfer to reduce the N 2 O generation pathway and increase the catalytic reaction sites, thus enhancing the overall catalytic performance.