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

Silver-manganese, silver-cobalt and silver-cerium composite oxides supporte d an Al2O3 catalysts were prepared and used for carbon monoxide acetone, py ridine oxidation and GO-NO reaction. Results were compared to that of the i ndividual 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 desorptio n peaks are attributed to the decomposition of the crystalline Ag2O phase a nd the dispersed Ag2O phase (I) and (II). For binary oxide catalysts, the s ilver promotes the reduction of manganese oxide and cobalt oxide. This proc ess is attributed to the spillover of hydrogen from silver atoms to mangane se oxide or cobalt oxide. However, the manganese oxide, cobalt oxide and ce rium oxide can promote the oxygen reproduction of silver oxide catalyst. Th e activity of binary oxide catalysts is higher than that of individual cata lysts for CO, acetone, pyridine oxidation and GO-NO reaction. There is a co operative action in binary oxide catalysts. (C) 1998 Elsevier Science B.V. All rights reserved.