Compatibility Optimization of Mn-Mo-W-O_x Catalyst for Selective Catalytic Reduction of NO by NH₃

A series of Mn-Mo-W-O_x/cordierite and Mn-Mo-W-O_x/TiO₂ catalysts were prepared by volumetric impregnation method and tested for selective catalytic reduction of NO by NH₃. Mn-Mo-W-O_x compatibility was designed to obtain the optimum proportion. These catalysts were characterized by XRD, N₂-BET, Py-IR, SEM and XPS to analyze the phase structure, specific surface area, acid content and the catalyst surface element. Results showed that the catalyst with the Mn/Mo/W molar ratio of 10:0.5:1, supported on TiO₂, exhibited the best catalytic activity for NH₃-SCR. The appropriate addition of Mo could enlarge the specific surface area, increase the amount of Lewis acid sites and the concentration of Mn⁴⁺, which was beneficial for the catalytic activity at the high temperatures. In addition, TiO₂ as the catalyst carrier could increase the specific surface area and the amount of acid sites, so that the catalytic performance would be enhanced.