Fabrication of Cu2O-RGO/BiVO4 nanocomposite for simultaneous photocatalytic CO2 reduction and benzyl alcohol oxidation under visible light

Cu2O-RGO/BiVO4 nanocomposite was obtained via a thermal treatment of Cu precursor in the presence of the pre-obtained RGO/BiVO4. The product was fully characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) and UV-vis diffuse reflectance spectroscopy (DRS). It was found that olive-shaped BiVO4 of ca. 1.0-L2 mu m as well as small nanoparticles of Cu2O with a dimension of 40-50 nm were deposited on the surface of RGO. The as-formed Cu2O-RGO/BiVO4 nanocomposite exhibited superior photocatalytic activity for simultaneous CO2 reduction and benzyl alcohol oxidation under visible-light irradiation, as compared with bare Cu2O and RGO/BiVO4 nanocomposite. The superior photocatalytic performance observed over Cu2O-RGO/BiVO4 nanocomposite may be ascribed to the existence of the Z-Scheme charge transfer pathway in the nanocomposite, i.e., the photogenerated electrons transferred from BiVO4 to Cu2O to recombine with the photogenerated holes via RGO acting as a good electron mediator. The study demonstrates a high potential of using RGO to fabricate Z-Scheme photocatalytic systems for a variety of photocatalytic applications.