Catalytic ozone oxidation toluene over supported manganese cobalt composite: influence of catalyst support

In this study, the manganese cobalt composite (Mn-Co)-loaded SiO2, MgO, TiO2, gamma-Al2O3 and silicalite-1 were prepared by ultrasonic complexation method. The catalysts were characterized by XRD, BET, SEM, TEM, H-2-TPR and XPS, and the activity of catalytic oxidation of toluene was evaluated. It was found that Mn-Co loaded gamma-Al2O3 (Mn2CoOx/gamma-Al2O3) exhibited excellent catalytic activity. When the gas hour space velocity (GHSV) was 45,000 h(-1), the removal rate of toluene reached 91.2% within 5.5 h, and the selectivity of CO2 was 71.10% at ambient temperature. The operation of Mn2CoOx/gamma-Al2O3 at different temperatures was investigated, and the better toluene removal efficiency more than 80% after reacting 9h was obtained at 50 degrees C. The characterization results showed that better catalytic activity is related to smaller grain size, higher Mn3+/Mn4+ values and the relative content of active oxygen species (O-II + O-III). Increased amounts of low state species easily led to the imbalance of the catalyst surface charge and promoted the formation of more oxygen vacancies.