Optimization of Robust FeMnSmO<i><sub>x</sub></i> Catalyst for Low-Temperature (<150 °C) NH<sub>3</sub>–SCR of NO<i><sub>x</sub></i>
Xiaoyu Ji, Yandi Cai, Bifeng Zhang, Haowei Yu, Qinglong Liu, Xiuwen Wang, Annai Liu, Qiuhui Qian, Qing Tong, Wei Tan, Lin Dong
Abstract
To realize the efficient denitrification of low-temperature (<150 °C) flue gas in nonelectric industries, the most promising strategy is to develop NH 3 selective catalytic reduction (NH 3 –SCR) catalysts with superior low-temperature activity. Conversely, the low working temperature offered great flexibility for tuning the calcination temperature during catalyst manufacturing. Herein, starting with the Sm-doped FeMnO x catalyst, an easy but practical strategy of calcination temperature regulation was proposed. With the increase in the calcination temperature from 300 to 600 °C, the low-temperature activity of FeMnSmO x increased first and then decreased, and 500 °C was the optimal calcination temperature. Detailed characterizations revealed that the calcination at 500 °C could better facilitate the formation of more weak acid sites and enhance the redox properties of FeMnSmO x, thus promoting the low-temperature NH 3 –SCR activity. NH 3 –SCR reaction on FeMnSmO x followed the “NO-assisted NH 4 NO 3 pathway”, in which gaseous NO would assist the reduction and decomposition of NH 4 NO 3 .