Effect of La2O3 on Catalytic Performance of Au/TiO2 for CO Oxidation

Pure TiO2 and La-doped TiO2 were prepared by the sol-gel method. Au was supported on TiO2 by the deposition-precipitation (DP) method, and its catalytic activity for CO oxidation was tested. The results showed that doping La in Au/TiO2 could improve its catalytic activity obviously for CO oxidation. The analyses of X-ray diffraction (XRD), ternperature-programmed desorption (TPD), and Brunauer-Emmett-Teller (BET) surface area further showed that the presence of La in TiO2 not only increased its surface area and restrained the growth of TiO2 crystallites, but could also enhance the microstrain of TiO2. In terms of O-2-TPD, a new adsorbed species O- appeared on the surface of La-doped TiO2. The results of in-situ Fourier transform-infrared (FT-IR) spectroscopy illustrated that the high activity of Au/La2O3-TiO2 was attributed to the presence of La promoting the reactivity of CO adsorbed on the Au site and the formation of the second active site on the surface of TiO2.