Preparation of Highly Loaded LaMnOx/SBA-15 Catalyst and Its Toluene Combustion Performance

A highly loaded LaMnOx/SBA-15 catalyst (60%) was prepared by step coating NH3/water vapor-induced internal hydrolysis (VIH) and characterized by X-ray diffraction, N2 adsorption-desorption, and temperature-programmed reduction (H2-TPR). Its catalytic performance for toluene combustion was also evaluated. The results showed that the VIH process clearly improved the activity of the LaMnOx/SBA-15 catalyst. Using a toluene concentration of 0.86% and a GHSV of 5000 h−1, a 50% toluene conversion was obtained at 205 °C for the LaMnOx/SBA-15 sample prepared by the VIH process. This temperature was 105 °C lower than that for the sample prepared by conventional impregnation. N2 adsorption-desorption and H2-TPR revealed that the VIH process improved the distribution of the LaMnOx active phase in the pores of SBA-15 and improved its reduction properties. The optimal VIH conditions were a temperature of 60 °C and a reaction time of 40 min.

摘要：采用逐层负载-孔道内氨/水蒸气原位羟化法制备了高负载量的 LaMnOx/SBA-15 催化剂, 并采用 X 射线衍射、N2 吸附-脱附和程序升温还原等技术对催化剂进行了表征, 考察了其催化甲苯燃烧的性能. 结果表明, 孔道内氨/水蒸气原位羟化提高了 LaMnOx 活性物种在 SBA-15 孔道内的分散度和还原性, 显著改善了高负载量的 LaMnOx/SBA-15 催化剂的活性. 在空速 5000 h–1 的条件下, 温度升至 205 °C 时甲苯转化率即可达 50%, 较之普通浸渍法制得的催化剂上甲苯达到该转化率所需温度降低了约 105 °C. 实验得到 LaMnOx/SBA-15 的适宜原位羟化处理温度为 60 °C, 处理时间 40 min. 

Graphical abstractA step coating NH3/water vapor-induced internal hydrolysis (VIH) method was used to prepare the highly loaded LaMnOx/SBA-15 catalyst. The LaMnOx species was scattered in the pores much better.Figure optionsDownload full-size imageDownload as PowerPoint slide