Synthesis of novel highly-dispersed manganese oxide on porous calcium silicate for the catalytic oxidation of toluene

Abstract

Herein, a series of novel porous calcium silicate (PCS)-supported manganese oxide (MnO_x) catalysts are first prepared by an impregnation method using three different manganese precursors (manganese acetate, manganese nitrate and manganese chloride) for toluene oxidation. We find that the catalyst prepared with manganese acetate (MnO_x–Ac/PCS) exhibits the best catalytic performance with a T₅₀ of 280 °C and a T₉₀ of 302 °C, as well as the highest CO₂ yield of 85.36%. The characterization techniques of N₂ adsorption–desorption isotherms, XRD, SEM, TEM, XPS, EPR and TPR are used to reveal the structure–activity relationships of these PCS-supported MnO_x catalysts. The results demonstrate that the excellent catalytic performance of MnO_x–Ac/PCS is related to the abundant oxygen vacancy and higher content of adsorbed oxygen, which can quickly replenish the consumed lattice oxygen during the reaction. This work presents a new insight into the effect of different manganese precursors on the catalytic performance of MnO_x catalysts.