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 Ce0.62Zr0.38O2mixed oxide has been synthesized usinga simultaneous deposition-precipitation method. Different Au:Pd ratios were obtained maintaining Auloadings constant and varying Pd content. Elemental analysis, X-ray diffraction, N2physisorption,X-rayphotoelectron spectroscopy, scanning transmission electron microscopy-high angle annular dark field(STEM-HAADF) and X-ray energy dispersive spectroscopy (XEDS) techniques have been employed tocharacterize these catalysts. The catalytic activities for selective oxidation of glycerol over these bimetalliccatalysts have been evaluated, a synergistic effect being observed. Thus, the bimetallic Au-Pd catalystwith the lowest Pd content was the one exhibiting the highest catalytic activity among all the preparedcatalysts. Oxidation at 700◦C of the bimetallic 2.2AuPd/Ce0.62Zr0.38O2catalyst led to an increase of thecatalytic activity for the selective oxidation of glycerol, which seemed to be due to the formation of alarger fraction of bimetallic Au-Pd alloy-type nanoparticles after oxidation at higher temperatures.