Reactive oxygen species (ROS) can be produced by interactions between sunlight and light-absorbing substance in natural water environment and can completely destroy various organic pollutants in wastewaters. In this study, CoS2 and CoS2-fullerene were irradiated by visible light respectively. The generation of reactive oxygen species were detected through the oxidation reaction from 1,5-diphenyl carbazide (DPCI) to 1,5-diphenyl carbazone (DPCO). In comparison with the separate effects of CoS2 and fullerene nanoparticles, the photochemically effect of-the fullerene photosensitized CoS2 composites is increased significantly due to the synergetic effect between the fullerene and the CoS2 nanoparticles. (C) 2013 Elsevier Ltd. All rights reserved.