Enhanced activity and alkali metal resistance in vanadium SCR catalyst via co-modification with Mo and Sb

Abstract

A series of V_0.04W_0.03Mo_xSb_y/TiO₂ catalysts was prepared by impregnating various contents of Mo and Sb. The optimum V_0.04W_0.03Mo_0.015Sb_0.018/TiO₂ catalyst exhibited enhanced SCR activity in a wide temperature range of 160–320 °C, together with excellent SO₂ and H₂O resistance. The addition of an appropriate amount of Mo and Sb could strengthen the alkali metal resistance of the V_0.04W_0.03/TiO₂ catalyst. The Mo and Sb co-modified catalyst exhibited a large specific surface area. The XPS and EPR results confirmed the presence of abundant V⁴⁺ and O_β on the modified catalyst. The TPR and TPD experiments revealed that the enhanced low-temperature redox ability and improved surface acidity played a key role in the superior catalytic activity and alkali metal resistance over the V_0.04W_0.03Mo_0.015Sb_0.018/TiO₂ catalyst. The in situ DRIFTS results revealed that the reaction mechanism followed the E–R mechanism over the V_0.04W_0.03Mo_0.015Sb_0.018/TiO₂ catalyst at 180 °C. Additionally, the inhibitory effect of K was mainly attributed to the destruction of the redox ability and surface acidity of the catalyst.