▎ 摘　　要

A highly efficient synthetic route was successfully developed to prepare crystallized and well dispersed Cu, Cu2O, and CuO nanoparticles (NPs) on reduced graphene oxide (rGO) by controlling the impregnation condition of a copper-precursor (Cu(NO3)(2)center dot 3H(2)O) on graphene oxide (GO) and subsequent thermal treatments. The morphological and chemical structures of the nanocomposites were systemically evaluated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), X-ray absorption fine structure (XAFS), and transmission electron microscopy (TEM). The rGO based CuOx nanocomposites exhibited a much higher catalytic activity than bare CuOx NPs toward the decomposition reaction of dye molecules under visible light illumination. Among the CuOx/rGO nanocomposites, CuO/rGO showed excellent photocatalytic efficiency and recyclability without significant loss of activity. Based on the XPS, XRD, XAFS, and TEM results, the high photocatalytic efficiency of the CuO/rGO can be attributed to the synergistic combination of dye adsorptivity and electron acceptability of the rGO, the surface hydroxyl species in the CuO/rGO, and the narrow band gap and smaller size of the CuO NPs. This work could be applied to the removal and water treatment of waste dye. (C) 2016 Elsevier B.V. All rights reserved.