采用等体积浸渍法制备系列Mn-Mo-W-Ox/堇青石和Mn-Mo-W-Ox/TiO2催化剂,用于选择性催化还原NO.通过Mn、Mo、W3种元素不同配比对催化剂配伍进行优化,确立Mn-Mo-W-Ox最佳配比.采用XRD、N2-BET、Py-IR、SEM以及XPS等表征分析催化剂的固相结构、比表面积、酸量、表面形貌和表面元素.结果表明:当Mn/Mo/W元素摩尔比为10:0.5:1,载体为TiO2时,催化剂的催化性能最优.适量Mo掺入Mn-W-Ox催化剂可以增大其比表面积,提高催化剂表面L酸酸量以及Mn4+离子浓度,从而有效提高了催化剂高温活性.载体替换为TiO2时催化剂的比表面积和酸量明昂根高.从而增强了催化剂的脱硝性能.
A series of Mn-Mo-W-Ox/cordierite and Mn-Mo-W-Ox/TiO2 catalysts were prepared by volumetric im- pregnation method and tested for selective catalytic reduction of NO by NH3. Mn-Mo-W-Ox compatibility was de- signed 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 ca- talytic 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, TiO: as the catalyst carrier could increase the specific surface area and the amount of acid sites, so that the catalytic performance would be enhanced.