Preparation of Ag-Mn/γ-Al₂O₃-TiO₂ catalysts by complexation-impregnation process with citric acid and its application in propane catalytic combustion

A series of Ag-Mn/γ-Al₂O₃-TiO₂ catalysts were prepared by different impregnation procedures. The catalysts were characterized by BET, XRD, TEM, XPS and H₂-TPR, and the catalytic properties were investigated by propane catalytic combustion. Results show that compared with the conventional impregnation method, complexation-impregnation procedure with citric acid promotes the dispersion of Ag and Mn particles on the surface of catalyst and strengthens the interaction between Ag and Mn, so as to increase the relative content of reactive oxygen species and improve the reducibility of catalysts, which further improves the catalytic activity of propane combustion reaction. Especially, the Ag₁Mn₃/γ-Al₂O₃-TiO₂ catalyst prepared by complexation-impregnation process with citric acid exhibits the best activity for propane catalytic combustion with 90% conversion at 263℃.