Promotion of Phosphorus on Carbon Supports for MnOx-CeO2 Catalysts in Low-Temperature NH3-SCR with Enhanced SO2 Resistance

摘要

MnOx-CeO2/P-CA catalysts were prepared via incipient wetness impregnation of Mn(NO3)(2) . 4H(2)O and Ce(NO3)(3) . 6H(2)O over phosphorus-doped carbon aerogels (P-CA) for selective catalytic reduction of NO by NH3 (NH3-SCR). The results show that P doping on carbon support significantly promotes the NH3-SCR performance of MnOx-CeO2/P-CA catalysts. P modification can improve the hydrophilicity of carbon support and facilitate the dispersion of MnOx-CeO2 components on carbon surface, which enhances the electronic interactions between MnOx and CeO2. The optimal catalyst 10 %MnOx-CeO2/P-CA shows higher surface acidity, more Mn4+ and Ce3+, and a larger amount of surface chemisorbed oxygen (O-alpha) than that of 10 %MnOx-CeO2/CA catalyst. As a result, even though in the company of SO2, more NO can be adsorbed and oxidized over the 10 %MnOx-CeO2/P-CA catalyst to generate more NO complexes, alleviating the suppression of SO2 on the SCR reaction via Langmuir-Hinshelwood (L-H) mechanism, and thus the SO2 resistance is enhanced.