Iron Oxide as a Promoter for Toluene Catalytic Oxidation Over Fe-Mn/γ-Al2O3 Catalysts

Fe-Mn/gamma-Al2O3 catalysts that prepared by the wet-impregnation method were used to degrade toluene, a VOCs model compound. The results indicated that the 10Fe-15Mn/gamma-Al2O3 exhibited 95% of toluene conversion as well as 95% of CO2 yield at 300 degrees C. The Fe-Mn/gamma-Al2O3 showed a better toluene oxidation activity with respect to the Fe/gamma-Al2O3 and Mn/gamma-Al2O3. The introduction of Fe into the Mn/gamma-Al2O3 resulted in higher surface area, higher Mn3+/(Mn3+ + Mn4+) ratio, lower reduction temperature, and homogenous distribution of Mn. Meanwhile, the co-exist of the Fe3+ and Mn3+ over the 10Fe-15Mn/gamma-Al2O3 also favored for the oxygen transfer, which may enhance the catalytic oxidation performance. The initial toluene was adsorbed on surface of the catalysts and formed benzoyl oxide (C6H5-CH2-O), and then the benzoyl oxide (C6H5-CH2-O) was oxidized to benzaldehyde. Furthermore, the benzaldehyde was further oxidized to form benzoic acid that could be converted to CO2 and H2O. Graphic