Enhancement effects of Er modification on comprehensive performance of FeMn/TiO2 catalysts for selective reduction of NO with NH3 at low temperature

Erbium (Er) has been used as a novel dopant to modify FeMn/TiO2 catalyst for the selective catalytic reduction of NO with NH3. The optimized ErxFeMn/TiO2 catalyst exhibited excellent catalytic performance at low temperature under a high space velocity of 30,000 h 1. The temperature window for NO conversion efficiency higher than 80% ranged from 100. to 240 degrees C. The catalysts were characterized using XRD, BET, H-2-TPR, NH3-TPD, XPS, TGA and In-situ DRIFT. The results showed that Er modification on FeMn/TiO2 catalysts increased the specific surface area, dispersion, reducibility, Mn4+ concentration, and especially the concentration of Lewis acid sites and surface chemisorbed labile oxygen, resulting in an excellent catalytic performance at low temperature. Additionally, Er modification also restrained the formation of sulfate and/or bisulfate salts, which improved the resistance to SO2 and H2O of the catalyst.