Benzene oxidation with ozone over MnOx/SBA-15 catalysts

Catalytic oxidation of benzene with ozone has been studied using manganese oxides with two different manganese precursors, Mn(NO3)2 and Mn(CH3COO)2, supported on SBA-15 (MnOx/SBA-15). The catalysts were characterized by X-ray diffraction, N2 adsorption–desorption, Raman spectroscopy, and H2-temperature programmed reduction. The manganese nitrate (MN) precursor primarily resulted in large particles on the silica support, while the manganese acetate (MA) precursor mainly resulted in a highly dispersed manganese oxide on the silica support. The catalytic activity was dependent upon ozone concentration, reaction times, and the amount of Mn loading. Higher benzene conversion, O3 conversion, and COx yield were observed for MnOx-MA/SBA-15 catalyst over MnOx-MN/SBA-15, due to the highly dispersed manganese oxides on the supports, and the higher oxygen mobility. The 15 wt% MnOx-MA/SBA-15 catalyst shows the highest catalytic activity of all the catalysts considered in this study.