Synergistic effect of bimetallic Au-Pd supported on ceria-zirconia mixed oxide catalysts for selective oxidation of glycerol

Abstract

A series of bimetallic Au-Pd catalysts supported on Ce0.62Zr0.38O2 mixed oxide has been synthesized using a simultaneous deposition-precipitation method. Different Au:Pd ratios were obtained maintaining Au loadings constant and varying Pd content. Elemental analysis, X-ray diffraction, N2 physisorption, X-ray photoelectron spectroscopy, scanning transmission electron microscopy-high angle annular dark field (STEM-HAADF) and X-ray energy dispersive spectroscopy (XEDS) techniques have been employed to characterize these catalysts. The catalytic activities for selective oxidation of glycerol over these bimetallic catalysts have been evaluated, a synergistic effect being observed. Thus, the bimetallic Au-Pd catalyst with the lowest Pd content was the one exhibiting the highest catalytic activity among all the prepared catalysts. Oxidation at 700°C of the bimetallic 2.2AuPd/Ce0.62Zr0.38O2 catalyst led to an increase of the catalytic activity for the selective oxidation of glycerol, which seemed to be due to the formation of a larger fraction of bimetallic Au-Pd alloy-type nanoparticles after oxidation at higher temperatures.