Benzene oxidation with ozone over MnOx/SBA-15 catalysts

Abstract

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, N-2 adsorption-desorption, Raman spectroscopy, and H-2-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, O-3 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. (c) 2012 Elsevier B.V. All rights reserved.