Property of Pt-Ag Alloy Nanoparticle Catalysts in Carbon Monoxide Oxidation

Alumina-supported platinumsilver alloy nanoparticle (PtAg/Al2O3) catalysts with different particle composition have been prepared using a wet chemistry method and studied for the property in carbon monoxide oxidation reaction. The PtAg alloy catalyst exhibits significantly improved activity and largely decreased activation energy barrier compared to those of both pure Pt and pure Ag catalysts in the room temperature range. The LangmuirHinshelwood mechanism, in which surface Pt active sites chemisorb CO and adjacent Ag sites activate O-2, was proposed and discussed to explain the promoted CO oxidation kinetics on the PtAg alloy. Thermal stability of the PtAg alloy catalyst under the reaction condition was also investigated using in situ Fourier transform infrared spectroscopy experiments and transmission electron microscopy characterizations.