Metal-support and preparation influence on the structural and electronic properties of gold catalysts

Abstract Nanostructured gold catalysts supported on CeO 2 and SiO 2 were prepared by the deposition–precipitation (DP) and the solvated metal atom dispersion (SMAD) techniques. The structural and electronic properties of the catalysts were investigated by X-ray diffraction (XRD), X-ray absorption spectroscopy (XAS) and X-ray photoelectron spectroscopy (XPS). Gold was found as small metal nanoparticles (cluster size ∼2 nm) in the SMAD-prepared samples and in ionic state in the DP catalysts. The catalytic activity of the samples was tested in the reaction of low temperature CO oxidation. Gold nanosized particles in a pure metallic state exhibited a worse catalytic performance, both on ceria and silica. The presence of non-metallic Au species seems to be the main requisite for the achievement of the highest CO conversion at the lowest temperature. The higher activity of the Au/CeO 2 (DP) sample with respect to the Au/SiO 2 (DP) catalyst can be ascribed to a better stabilization of the Au +1 ions, probably as AuO - species, by the cerium oxide.