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, N-2 adsorption-desorption, and temperature-programmed reduction (H-2-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 degrees C lower than that for the sample prepared by conventional impregnation. N-2 adsorption-desorption and H-2-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 degrees C and a reaction time of 40 min.