Iodine-sensitized Bi4Ti3O12/TiO2 composite photocatalyst was synthesized via the formation of Bi4Ti3O12/TiO2 heterostructure followed by being loaded with I-2/I-. The photocatalyst was characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, diffusive reflectance UV-vis spectroscopy and photoluminescence spectra. I-sensitized Bi4Ti3O12/TiO2 photocatalyst exhibited red shift of the absorption edge and strong enhancement of absorption in visible light region owing to the absorption of Bi4Ti3O12 and I-2. I sensitized Bi4Ti3O12/TiO2 composite displayed much higher photocatalytic activity for the photodegradation of phenol under visible light irradiation than TiO2 (P25), Bi4Ti3O12 and Bi4Ti3O12/TiO2. The enhanced photocatalytic activity of I-sensitized Bi4Ti3O12/TiO2 was attributed to its novel heterostructure and the existence of I-2/I- redox mediator, both of which were responsible for its strong absorption in the visible region and low recombination rate of electron-hole pairs. (C) 2013 Elsevier B.V. All rights reserved.