Calcium bismuthate (CaBi6O10/Bi2O3) composites synthesized using a simple deposition method were used as visible-light driven photocatalysts for dye degradation in polluted water and their activities were investigated. The photocatalysts were characterized via X-ray 'diffraction (XRD), Brunauer-Emmett-Teller (BET) analysis, Raman spectroscopy (Raman), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), and UV-vis diffuse reflectance spectroscopy (DRS). The photocatalytic activity of the CaBiO composites was evaluated through the decomposition of methylene blue in an aqueous solution under visible light irradiation (>420 nm). The CaBi6O10/Bi2O3 binary semiconductors exhibit better photocatalytic properties compared with those of the single-phase CaBi6O10 or Bi2O3. Based on the results of the energy band position calculation and the terephthalic acid photoluminescence (PL) probe experiment, the effective electron-hole separation in the two semiconductors is considered the cause of the high activity. (c) 2012 Elsevier B.V. All rights reserved.