Ag-modified SmMn2O5 catalysts for CO and C3H8 oxidation

A series of Sm-Mn oxides (SmMnO3, SmMn2O5 and Sm0.9Ag0.1Mn2O5) of perovskite-type and mullite crystal phases were synthesized for the catalytic oxidation of CO and C3H8. The Sm0.9Ag0.1Mn2O5 composition showed the highest catalytic activity among the series of solids, especially for the CO oxidation to CO2 with T50 and T90 values of 60 and 95 °C, respectively. The catalysts were characterized by powder XRD, Raman, BET, XPS, and H2-TPR. It was found that the catalytic performance of the solids was correlated well with their redox properties. Synergetic effects between Ag-related species and the mullite phase resulted in more active surface oxygen species and remarkably lowered the reduction temperature of the Sm0.9Ag0.1Mn2O5 solid. Figure Caption: CO conversion over the catalysts as functions of temperature. [Display omitted] •Sm-Mn mullite had better catalytic activity than Sm-Mn perovskite for the oxidation of CO, CH8, and CH4.•The Ag-doping into the Sm-Mn mullite could further improve its catalytic activity, especially for the oxidation of CO.•The Ag-related species could increase the reducibility of the Sm-Mn mullite catalyst.