Insight into the performance-boosting mechanism of Mn3O4 prepared by reduction method for oxidation of toluene

Abstract

Toluene, a typical volatile organic compound (VOCs), is harmful to environment . There are significant challenges for preparing high-perform catalyst and understanding the reaction mechanism of toluene oxidation over trimanganese tetroxide (Mn₃O₄). Herein, a spiny spherical Mn₃O₄-H was prepared by reduction method. Mn₃O₄-H exhibits higher catalytic activity and maintains a stable operation of >90 % conversion of toluene at 230 °C for 100 h. The stronger adsorption ability to oxygen and toluene, abundant surface adsorbed oxygen, the higher lattice oxygen activity, and the stronger redox ability are essential to the performance of Mn₃O₄-H. The in-situ DRIFTS confirm the branched methyl group on toluene is preferentially oxidized at low temperature, and intermediates including unidentate benzoate and benzene ring metal complexes adsorbed on Mn₃O₄-H were identified. These findings not only clarify the reaction pathway of toluene oxidation over Mn₃O₄, but provide a novel design strategy for toluene removal catalysts.