Catalyst characterization and activity of Ag-Mn, Ag-Co and Ag-Ce composite oxides for oxidation of volatile organic compounds

Silver-manganese, silver-cobalt and silver-cerium composite oxides supported an Al2O3 catalysts were prepared and used for carbon monoxide acetone, pyridine oxidation and GO-NO reaction. Results were compared to that of the individual catalysts. The catalysts were characterized by means of XRD, H-2-TPR and O-2-TPD. For each individual Ag/Al2O3 catalyst, three O-2 desorption peaks are attributed to the decomposition of the crystalline Ag2O phase and the dispersed Ag2O phase (I) and (II). For binary oxide catalysts, the silver promotes the reduction of manganese oxide and cobalt oxide. This process is attributed to the spillover of hydrogen from silver atoms to manganese oxide or cobalt oxide. However, the manganese oxide, cobalt oxide and cerium oxide can promote the oxygen reproduction of silver oxide catalyst. The activity of binary oxide catalysts is higher than that of individual catalysts for CO, acetone, pyridine oxidation and GO-NO reaction. There is a cooperative action in binary oxide catalysts. (C) 1998 Elsevier Science B.V. All rights reserved.