Au/CeO2 Catalysts for Catalytic Abatement of CO, CH3OH and (CH3)2O: Effect of Preparation Method

摘要

Two different synthesis routes, in particular deposition-precipitation (DP) and modified deposition-precipitation (MDP) have been used for preparation of gold/ceria catalysts. The catalysts have exhibited significant differences in CO, CH3OH and (CH3)2O oxidation. The most pronounced effect of different preparation methods was registered in the CO oxidation reaction. DP-prepared catalyst showed high ability to oxidize CO at room temperature. Microscopic measurements have evidenced formation of very small gold particles (d below 1 nm) on the surface of DPprepared catalyst. In contrast, only large gold particles with average size about 15 nm were observed in MDP-prepared sample. A detailed characterization by FTIR spectroscopy after CO adsorption at 90 K and TPR measurements has been carried out with aim to unravel the impact of preparation method on the structural and catalytic properties of the catalysts. The catalytic behavior was explained with the large differences in the gold dispersion and in the number of active gold sites in intimate contact with ceria surface defects.