Enhance catalytic activity for CO oxidation over titania supported gold catalysts that dispersed on SiO(2)

Abstract

The enhanced dispersion of gold on TiO(2) was achieved by dispersing TiO(2) onto a high-surface-area SiO(2) powder support. High temperature reduction, at 773-873 K, in hydrogen leads to very active gold nanoparticles on the support surfaces for CO oxidation at room temperature. The surface sol-gel method results better dispersion for both TiO(2) and Au, and higher activity for CO oxidation than that by the conventional impregnation method. Metallic gold with slightly negative charge was evidenced by X-ray photoelectron spectroscopy (XPS) and in situ transmission infrared spectroscopy (FTIR) using CO as a probe. The obtained Au/TiO(2)/SiO(2) catalysts show better stability and higher activities for CO oxidation than that for Au/TiO(2). The promotion effects may origin from the formation of thin layer and small crystalline particles of TiO(2) anchored on SiO(2) , leading to a better dispersion of small Au nanoparticles and sinter resisting. (C) 2010 Elsevier B.V. All rights reserved.