CO Oxidation over silica-based Au catalysts

Gold nanoparticles deposited on metal oxides are being actively investigated as catalysts . However, few reports concerning gold deposited on silica as catalysts have appeared because gold particles with less than 5 nm on silica supports are difficult to be synthesized. Recently we developed a methodology to synthesize gold/silica catalysts under the basic condition using Au(en)2Cl3 (en = ethylenediamine) as precursor , which is easy to prepare small gold nanoparticles on the silica support. Herein we further studied the catalytic activity of the Au/silica catalyst for CO oxidation. The catalysts were characterized by the means of the tunneling electronic microscopy (TEM), diffuse-reflectance infrared Fourier transform spectroscopy (DRIFTS), XRD and mass spectroscopy (MS). Multicomponent Au/MOx/SiO2 catalysts with addition of metal oxide (MOx) (M=Ti, Al, Fe, Zn and Mg etc) were also examined. The results showed that the catalytic performance was not only related with the gold particle size, but also surface properties such as acidic/basic properties, the basic surface was beneficial for the catalytic performance, meanwhile, the catalysts also exhibited a highly thermal stability compared with the Au/TiO2 catalyst.