Cocatalyst modification of photocatalysts is an important strategy to enhance the photocatalytic performance by promoting effective separation of photoinduced electron-hole pairs and providing abundant active sites. In this study, a facile in situ photodeposition method was developed to prepare amorphous CoSx-modified TiO2 photocatalysts. It was found that amorphous CoSx nanoparticles were solidly loaded on the TiO2 surface, resulting in a greatly improved photocatalytic H-2-evolution performance. When the amount of amorphous CoSx was 10 wt%, the hydrogen evolution rate of the CoSx/TiO2 reached 119.7 mu mol h(-1), which was almost 16.7 times that of the pure TiO2. According to the above experimental results, a reasonable mechanism of improved photocatalytic performance is proposed for the CoSx/TiO2 photocatalysts, namely, the photogenerated electrons of TiO2 can rapidly transfer to amorphous CoSx nanoparticles due to the solid contact between them, and then amorphous CoSx can provide plenty of sulfur active sites to rapidly adsorb protons from solution to produce hydrogen by the photogenerated electrons. Considering the facile synthesis method, the present cheap and highly efficient amorphous CoSx-modified TiO2 photocatalysts would have great potential for practical use in photocatalytic H-2 production. (C) 2017 Elsevier B.V. All rights reserved.