Ultraviolet (UV) light is introduced into the process of oxidizing CO over the TiO2 supported Pt/Co-B bicomponent catalyst (Pt/Co-B/TiO2). It is found that UV irradiation can promote the oxidation of CO and the preferential oxidation of CO in the presence of H-2 over Pt/Co-B/TiO2. This promoted effect of UV irradiation can also occur on other TiO2 supported Pt catalysts but not on the non-TiO2 supported Pt/Co-B catalysts. It is proposed that the photogenerated electrons induced by the photoexcitation of TiO2 can transfer to the Pt surface, resulting in the increase of surface electron density of Pt species. This further promotes the adsorption of CO and its activation at the surface Pt species, and then the subsequent oxidation of CO over Pt/Co-B/TiO2. This indicates that the photoexciatation behavior of TiO2 can be acted as an electron donator to promote the activity of the Pt/Co bicomponent catalyst for oxidizing CO. (C) 2011 Elsevier B.V. All rights reserved.