Cd1-xZnxS nanoparticles were prepared by a one-pot solvothermal process from Zn(CH3COO)(2), Cd(CH3COO)(2) and NaS2CNEt2 center dot 3H(2)O (sodium diethyldithiocarbamate, DDTC). The Cd1-xZnxS nanoparticles were characterized by X-ray powder diffraction, transmission electron microscope and high-resolution transmission electron microscope equipped with an energy-dispersive X-ray spectrometer. The absorption spectra of the Cd1-xZnxS nanoparticles can be tuned into visible region by modulating stoichiometric ratio between Zn and Cd. With the increase of Zn content, the Cd1-xZnxS nanoparticles showed an enhanced photocatalytic activity on degradation of 4-chlorophenol. The Cd1-xZnxS prepared under the optimal experimental condition (initial Zn/Cd = 3:1, 210 degrees C, 24 h. in ethanol) possessed the best photocatalytic activity. The conversion ratio could reach up to 84% after 12 h under irradiation of visible light for Cd1-xZnxS prepared in ethanol, which was obviously superior to those of products prepared in water. These results showed that both crystallinity and synthetic medium were responsible for the enhanced photocatalytic activity for 4-chlorophenol. (C) 2010 Elsevier Ltd. All rights reserved.