A novel porous CdS-TiO2 photocatalyst with large surface area and high crystallization degree was synthesized by in situ sulfurization of doped TiO2 under supercritical conditions. The CdS acted as a photosensitizing agent to activate TiO2 in visible light area, while the TiO2 acted as an electron acceptor to separate the photo-induced electrons from holes in the CdS. Under visible light irradiation, the as-prepared CdS-TiO2 exhibited high activity in photocatalytic degradation of 4-chlorophenol (4-CP) owing to the high surface area, the well dispersed CdS nanocrystals, and especially the strong interaction between CdS and TiO2 which greatly enhanced the photosensitizing effect of CdS and also effectively inhibited the recombination between photo-induced electrons and holes. Meanwhile, the CdS-TiO2 also displayed strong durability since the strong interaction between CdS and TiO2 could efficiently protect the CdS from photo-corrosion and leaching off. (C) 2011 Elsevier B.V. All rights reserved.