Promotion of Phosphorus on Carbon Supports for MnO _x −CeO ₂ Catalysts in Low‐Temperature NH ₃ −SCR with Enhanced SO ₂ Resistance

Abstract

Abstract MnO x −CeO 2 /P‐CA catalysts were prepared via incipient wetness impregnation of Mn(NO 3 ) 2 ⋅ 4H 2 O and Ce(NO 3 ) 3 ⋅ 6H 2 O over phosphorus‐doped carbon aerogels (P‐CA) for selective catalytic reduction of NO by NH 3 (NH 3 −SCR). The results show that P doping on carbon support significantly promotes the NH 3 −SCR performance of MnO x −CeO 2 /P‐CA catalysts. P modification can improve the hydrophilicity of carbon support and facilitate the dispersion of MnO x −CeO 2 components on carbon surface, which enhances the electronic interactions between MnO x and CeO 2 . The optimal catalyst 10 %MnO x −CeO 2 /P‐CA shows higher surface acidity, more Mn 4+ and Ce 3+ , and a larger amount of surface chemisorbed oxygen (O α ) than that of 10 %MnO x −CeO 2 /CA catalyst. As a result, even though in the company of SO 2 , more NO can be adsorbed and oxidized over the 10 %MnO x −CeO 2 /P‐CA catalyst to generate more NO complexes, alleviating the suppression of SO 2 on the SCR reaction via Langmuir‐Hinshelwood (L−H) mechanism, and thus the SO 2 resistance is enhanced.