A green approach to the fabrication of titania-graphene nanocomposites: Insights relevant to efficient photodegradation of Acid Orange 7 dye under solar irradiation

Environment friendly and efficient strategy for the preparation of titanium dioxide (TiO2)-graphene (GR) based hybrid nanocomposite has been demonstrated by simple chemical approach for the photodegradation of Acid Orange 7 (AO7) dye under solar irradiation. The resultant nanocomposite structure and composition has been characterized by Ultraviolet Diffusive Reflectance Spectroscopy (UV-DRS), Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Raman spectroscopy and X-ray diffraction (XRD) studies. The incorporation of TiO2 nanoparticles on the surface of GR was confirmed by High Resolution Transmission Electron Microscopy (HRTEM) and Field Emission Scanning Electron Microscopy (FESEM) studies. Electrochemical Impedance spectroscopy (EIS) and Cyclicvoltammetry (CV) studies revealed that the incorporation of GR with TiO2 nanoparticles significantly enhanced the redox property and electrical conductivity. During photocatalysis, the TiO2-GR nanocomposites have high photocatalytic activity compared with that of TiO2 towards AO7 dye degradation under solar light irradiation. The enhanced photocatalytic activity might be attributed to the role GR played as an electron acceptor and transporter in the composite film, which effectively suppressed the charge recombination and promoted the charge transfer within the composite. (C) 2013 Elsevier Ltd. All rights reserved.