CdxCuyZn1-x-yS photocatalysts which showed high photocatalytic performance under visible light irradiation (lambda >= 420 nm) even without Pt cocatalysts were synthesized by a simple coprecipitation method. The diffuse reflection spectra proved that both Cu and Cd could narrow the band gap. The calculation result indicates that the conduction and valence bands were tuned separately and independently by controlling the content of Cu and Cd in the photocatalyst. The dependence of the photophysical and photocatalytic properties upon the elemental composition was mainly due to the change of the band structure. (C) 2011 Elsevier B.V. All rights reserved.