Construction of graphene-WO3/TiO2 nanotube array photoelectrodes and its enhanced performance for photocatalytic degradation of dimethyl phthalate

Graphene and WO3 co-modified TiO2 nanotube array (GR-WO3/TNA) photoelectrodes were prepared through in-situ anodization and electrodeposition process. The morphology and structure were characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). Optical and photoelectrochemical (PECH) properties were investigated by UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS), photovoltage and photocurrent density. The photodecomposition performance was investigated through photocatalytic (PC) degradation of dimethyl phthalate (DMP) under Xenon light illumination. It was found that WO3 and GR were successfully electrodeposition onto the surface of TNA and all photoelectrodes showed highly ordered and vertically aligned nanotube array with anatase and rutile TiO2 mixcrystal structure. The decorated WO3 and GR on TNA photoelectrode reduced the recombination of photogenerated hole-electron pairs and prolonged the lifetime of photogenerated holes, thereby the visible light absorption and the PECH response of TNA photoelectrode were improved obviously, which would facilitate the formation of reactive species and improve the PC performance for DMP degradation. The kinetic constant of GR-WO3/TNA photoelectrode for PC degradation of DMP was 1.41 times that of TNA photoelectrode. (C) 2016 Elsevier Ltd. All rights reserved.