Catalytic oxidation of toluene over copper and manganese based catalysts: Effect of water vapor

Copper and manganese based catalysts with different supports were prepared by impregnation method for toluene oxidation in the presence of water vapor. Their catalytic activity was tested in the absence and presence of water vapor. The results showed that the activity of catalysts CuMn(y)Ox/γ-Al2O3 was higher than that of catalysts CuOx/γ-Al2O3 and MnOx/γ-Al2O3. The presence of water vapor had a negative effect on catalytic activity due to the competition of water molecules with toluene molecules for adsorption on surface active sites. The durability to water vapor followed the order: CuMn(1)Ox/Cordierite > CuMn(1)Ox/TiO2 > CuMn(1)Ox/γ-Al2O3.

The activity of the catalysts CuMn(y)Ox/γ-Al2O3 was higher than that of the catalysts CuOx/γ-Al2O3 and MnOx/γ-Al2O3. The presence of water vapor had a negative effect on the catalytic activity of the copper and manganese based catalysts due to the competition of water molecules with toluene molecules for adsorption on surface active sites. The degree of degradation in the catalytic activity of the catalysts by water vapor followed the order: CuMn(1)Ox/γ-Al2O3 > CuMn(1)Ox/TiO2 > CuMn(1)Ox/Cordierite, which was attributed to the different strength of interaction between water molecules and catalyst surfaces.Figure optionsDownload as PowerPoint slideHighlights
► CuMn(y)Ox/γ-Al2O3 have higher activity than CuOx/γ-Al2O3 and MnOx/γ-Al2O3.
► The formation of spinel phase Cu1.5Mn1.5O4 is responsible for enhanced activity.
► The presence of water vapor has negative influence on the catalytic activity.
► The activity decreases due to competition adsorption of H2O and toluene molecules.
► The interaction of H2O with the surfaces of CuMn(1)Ox/Cordierite is the weakest.