A novel approach was used to synthesize CdS/bentonite nanocomposite powders by the one-step thermal decomposition of complex ion [Cd(NH2CSNH2)(2)](2+) in the interlayer space of bentonite. XRD results demonstrated that the intercalation of CdS into the interlayer space of bentonite led to the expansion of layer spacing. The weight losses of the nanocomposite were via dehydration, decomposition of complex ion Cd (NH2CSNH2)(2)](2+) and dehydroxylation in the interlayer space of bentonite. Diffuse reflectance UV-visible spectra indicated that the absorption edge of the nanocomposites was blue-shifted as compared with bulk CdS due to the quantum size effect of CdS nanoparticles. The photocatalytic activity of hydrogen production for the nanocomposites was attributed to the synergistic effect between CdS and bentonite. A possible photocatalytic mechanism was proposed. (C) 2013 Elsevier B.V. All rights reserved.