Effect of support on the catalytic activity of manganese oxide catalyts for toluene combustion

The aim of this work was to study combustion of toluene (1000 ppm) over MnO2 modified with different supports. alpha-Al2O3 and gamma-Al2O3 obtained from Boehmite, gamma-Al2O3 (commercial), SiO2, TiO2 and ZrO2 were used as commercial support materials. In view of potential interest of this process, the influence of support material on the catalytic performance was discussed. The deposition of 9.5MnO(2) was performed by impregnation over support. The catalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), temperature programmed reduction and oxidation (TPR/TPO) and thermogravimetric analysis (TGA). The catalytic tests were carried out at atmospheric pressure in a fixed-bed flow reactor. 9.5MnO(2)/alpha-Al2O3(B) (synthesized from Boehmite) catalyst exhibits the highest catalytic activity, over which the toluene conversion was up to 90% at a temperature of 289 degrees C. Considering all the characterization and reaction data reported in this study, it was concluded that the manganese state and oxygen species played an important role in the catalytic activity. (C) 2012 Elsevier B.V. All rights reserved.