Preparation of Supported Au-Pd Bimetallic Catalyst and Its Catalytic Activity for CO Oxidation

The Au-Pd/SiO2 catalyst was prepared by impregnation of SiO2 with an alkaline HAuCl4 solution by an incipient wetness method.The effect of calcination temperature on the catalytic activity for CO oxidation was evaluated.The Au-Pd/SiO2 catalyst calcined in air at 673 K shows higher catalytic activity compared with the catalysts calcined at 623,723,or 773 K.The catalyst was characterized by N2 adsorption-desorption isotherms,X-ray diffraction,temperature-programmed reduction,CO temperature-programmed desorption,and X-ray photoelectron spectroscopy.The results indicate that the catalyst calcined at 673 K has the largest surface area and the smallest pore volume,and there exist Pd0,PdO,and Au0 phases on it.The formation of AuxPdy alloy does not favor the catalyst activity.