Novel In2O3/g-C3N4 composite photocatalysts were prepared by a simple thermal polymerization process. The samples were characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy with energy dispersive X-ray spectrometer, UV-vis diffuse reflection spectroscopy, Brunauer-Emmett-Teller surface area and thermogravimetric analysis. The prepared photocatalysts exhibited significantly enhanced photocatalytic performance towards the degradation of rhodamine B and 4-nitrophenol under visible light. The enhanced photocatalytic activity was generated from the matching energy levels of g-C3N4 and In2O3. It was found that holes (h(+)) and superoxide (center dot O-2(-)) were the main reactive species in the photocatalytic degradation of rhodamine B. (C) 2014 Elsevier B.V. All rights reserved.