The catalytic performance of Au/TiO2 for oxidizing CO in an H-2-rich stream under visible light irradiation was compared with that of Au/Al2O3. It is found that the visible light can promote the preferential oxidation of CO in the presence of H-2 over Au/TiO2, while it promotes the oxidation of CO but suppresses its selectivity in the same case over Au/Al2O3. The chemisorption results show that this visible light can promote the adsorption of CO in the presence of H-2 and its activation at Au sites over Au/TiO2, but suppress the adsorption of CO over Au/Al2O3. Based on the photo-electrochemical and other photo-response performances of two catalysts, it is proposed that the effect of visible light on CO adsorption and then oxidation over the supported Au catalyst may be dependent on the electron transfer behavior between Au and support induced by the localized surface plasmon resonance of Au nanoparticles. (C) 2014 Elsevier Inc. All rights reserved.