The highly efficient composite photocatalysts composed of grey-TiO2 and electrically conductive polyani-line (PANI) have been fabricated through an in situ polymerization of aniline in the presence of grey-TiO2 nanoparticles. The grey-TiO2 nanoparticles were prepared via a chemical reduction method by reducing bare white-TiO2 nanoparticles with aluminium powder under nitrogen, atmosphere. The morphology, crystalline structure and optical property of these PANI sensitized grey-TiO2 nanocomposites were investigated, and their photocatalytic activity in the phtocatalytic hydrogen generation and photodegradation of Rhodamine B were evaluated. Compared with grey-TiO2, the PANI/grey-TiO2 nanocomposites showed obviously improved photocatalytic efficiency both in the hydrogen production and the degradation of Rhodamine B. The hydrogen generation rate under simulated sunlight irradiation for PANI/grey-TiO2 nanocomposites was higher than that of most reported TiO2-based species. The photocatalytic mechanism analyses indicated that the PANI served as co-catalysts in promoting separation of photoinduced charges, and photoelectrons and holes.can transfer efficiently at interface of PANI and grey-TiO2, and thus inhibited the recombination of photo generated electron-hole pairs. This article elucidated a promising colored TiO2 based system, which can be applied in the photocatalytic reactors induced by sunlight irradiation. (C) 2017 Elsevier B.V. All rights reserved.