The effect of GO deposition on the photoelectrochemical properties of TiO2 nanotubes

•The direct use of expanded graphite to obtain the graphene oxide was proposed.•The graphene oxide sheets with an interlayer spacing of 0.42 nm was obtained.•The composite electrodes TiO2NT/GO are promising materials for photoanodes.

Graphene oxide (GO) was prepared by modified Hummers method from different carbon sources: expanded graphite and 4, 8, 12-pellets graphene. GO samples were studied by Scanning Electron Microscopy, Transmission Electron Microscopy, Raman Spectroscopy, X-ray diffraction and UV–vis spectroscopy. Then, GO was used to obtain TiO2/GO nanocomposite electrodes via electrochemical deposition process. Titanium dioxide nanotubes (TiO2NT) were obtained via anodization in electrolyte containing ethylene glycol with 1 wt% NH4F. Different conditions of deposition process of GO were examined. The resulting electrodes were characterized by SEM, TEM, X-ray diffraction, UV–vis spectroscopy and electrochemical methods. The results have shown that the expanded graphite is a good carbon source to synthesize highly oxidized graphene oxide. The composite electrodes have interesting electrochemical properties and are promising materials for photoanodes.

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