Enhancing Catalytic Ozonation of Acetone and Toluene in Air Using MnOx/Al2O3 Catalysts at Room Temperature

A series of MnOx/Al2O3 catalysts were synthesized by polyol and dry impregnation methods and calcined in the range of 400-800 degrees C. The impact of the preparation procedure and calcination temperature was investigated to enhance the catalytic degradation of a single component and binary mixtures of acetone and toluene at room temperature. The polyol method produces catalysts with a higher surface area, smaller cluster size, and lower oxidation state than the impregnation method. The results indicated that the oxidation state of manganese shifted to lower values by increasing the calcination temperature, which had a beneficial influence on the catalytic performance. As calcination temperature increases to 800 degrees C, the catalyst exhibited excellent catalytic activity in acetone degradation while no significant change was observed in degradation of toluene. In the binary mixture, toluene conversion was promoted whereas the acetone conversion was inhibited. X-ray absorption near-edge structure and extended X-ray absorption fine structure results of the spent catalysts showed that, unlike acetone, toluene altered the local structure of manganese oxides during the reaction. The catalyst was susceptible for the reduction process with toluene due to the accumulation of carbonaceous species resulting from incomplete oxidation of toluene.