Immobilizing ultrafine bimetallic PtAg alloy onto uniform MnO2 microsphere as a highly active catalyst for CO oxidation

Abstract Herein, a facile glycol reduction route is successful employed to synthesize bimetallic PtAg alloys with homogeneous distribution of sizes and elements. Experimental studies reveal that the ultrafine PtAg alloys with well-defined sizes from around 3.3 nm to 5.8 nm are immobilized onto MnO2 microsphere, which remarkably enhances the catalytic performances for CO oxidation. Importantly, quasi in-situ X-ray photoelectron spectroscopy (XPS) result reveals that both Mn and Pt ions on the surface of catalysts would realize alternating reduction-oxidation by CO and O2 molecules, and the oxygen vacancy sites could be replenished and excited by gas-phase O2.