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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