The composites of cuprous oxide (Cu2O)/reduced graphene oxide (RGO) were prepared with copper acetate adsorbed graphene oxide (GO) sheets as precursors followed by in-situ reduction in the presence of ethylene glycol. The as-synthesized nanocomposites were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, UV-Vis spectroscopy (UV), fluorescence spectroscopy (FL) and electrochemical impedance spectroscopy (EIS). The graphene sheets were decorated by spherical Cu2O particles with an average diameter of 200 nm. Such combination not only alleviates the agglomeration of Cu2O particles but also restrains the restacking of graphene. A preliminary study on the photo-catalytic activities of the Cu2O/RGO nanocomposites including photo-degradation of Rhodamine B dye and photo-reduction of CO2 under the illumination of simulated sunlight was carried out. The as-synthesized nanocomposites showed better photo-catalytic activity than the conventional Cu2O particles. The photo-degradation efficiency increased about 52% and the methanol yield improved about 53%. The enhancements of the photo-catalytic activities were attributed to the effective charge transfer from Cu2O to RGO, enhanced specific surface area and increased reaction sites. (C) 2014 Elsevier B.V. All rights reserved.