VIS-active TiO₂ films decorated by expanded graphite: impact of the exfoliation time on the photocatalytic behaviour

TiO₂/C nanocomposite films were applied on water treatment. Expanded graphite nanosheets (EG) were obtained by UVC-assisted liquid-phase exfoliation technique, without the addition of acids, surfactants, or aggressive oxidizing agents, which characterizes the process as an eco-friendly method. The carbon nanosheets were synthesized directly from graphite bulk at different times and deposited on TiO₂ films surface by airbrush spray coating method, forming a TiO₂/C heterojunction. The increase in the exfoliation time promoted a more efficient photocatalytic dye removal under visible light. Morphological modifications, changes in the electronic structure, and wide range of light absorption were observed from the TiO₂/C heterojunction formation. The results showed that hybrid TiO₂/C supported photocatalyst is a promise alternative for practical photocatalytic applications under sunlight.