Synthesis and characterization of graphene oxide - TiO2 thin films by sol-gel for photocatalytic applications

Titanium dioxide modified with graphene oxide (GO/TiO2) nanocomposite thin films were prepared on glass substrates by a sol-gel route using the dip coating technique for photocatalytic applications. The graphene oxide powders, fabricated through a modified Hummers' method, and the GO/TiO2 thin films were characterized by electron microscopy, XRD, Raman and UV-VIS spectroscopy to evaluate their structural, morphological and optical properties. The energy bandgap estimated for the thin films is in the range of 3.38–3.45 eV after an annealing at 450 °C; while the transmittance and the Raman intensity decreased significantly by increasing the amount of GO. The photocatalytic activity of the GO/TiO2 thin films, investigated by the blenching of methylene blue, showed a significant increment with the addition of GO; furthermore, the films exhibited potential applications in the photoreduction of CO2, in which a methanol production of 68.443 μmol cm−2 was observed after 5 h of reaction in the presence of UV light. •Graphene oxide/titanium dioxide (GO/TiO2) thin films were synthetized by dip-coating method.•The thin films shows a reduction of the energy band gap from 3.42 to 3.38 eV.•The CO2 photoreduction of the samples was studied under UV light irradiation as a function of the relative GO concentration.