Supported gold catalysts in SBA-15 modified with TiO2 for oxidation of carbon monoxide

Abstract

A series of gold catalysts active for CO oxidation were prepared in this research. Gold catalysts supported on titania-modified SBA-15 substrate with different TiO 2 loadings (0, 10, 20, 40 and 60 wt%) were prepared by the deposition–precipitation method. The experimental results revealed that the surface exposure of the Au + species and the optimized TiO 2 content were the primary factors influencing the activity and stability of Au/( x )TiO 2 /SBA-15 catalysts. Effect of Ti loading in the reaction of CO oxidation over gold catalysts supported on Ti-free and Ti- modified SBA-15 substrates: CO conversion as a function of the reaction temperature. This contribution describes the effect of SBA-15 support modification with variable quantity of TiO 2 (0, 10, 20, 40 and 60 wt%) on the catalytic response of supported gold catalysts in CO oxidation. All gold catalysts were prepared by the deposition–precipitation method. These catalysts were characterized by chemical analysis (ICP), N 2 adsorption–desorption isotherms, X-ray diffraction (XRD), UV–vis diffuse reflectance spectroscopy (UV–vis DRS), high resolution transmission electronic microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS). Catalytic activity was found to increase with the TiO 2 loading even though this increase was not lineal: the highest catalytic activity was observed for the catalyst loaded with 10 wt% TiO 2 . This behavior is explained in terms of the quantity of Au + species present on the surface of gold particles. In addition, an Au/TiO 2 reference sample was prepared and tested in CO oxidation reaction. This Au/TiO 2 catalyst exhibited the highest activity due to the higher gold dispersion achieved on the TiO 2 substrate. The importance of both Au + and Au 0 species present on the catalysts surface on the performance in the target reaction is discussed.