Influence of TiO2 dimension and graphene oxide content on the self-cleaning activity of methylene blue-stained photocatalytic films

In the present study, TiO2 and graphene oxide (GO)/TiO2 composite films were simply fabricated by hot-plate spray coating technique. The influences of TiO2 dimension and GO content on the self-cleaning activity of methylene blue (MB)-stained films were investigated. The matrix of anatase TiO2 quasi-cubic and octahedral particles in diameter of 6–9 nm (ST film) degraded 80% stained dye, much higher than those either in bigger size (30–50 nm) or in flower morphology due to the nano effect. Moreover, the photocatalytic performance of such nanostructured film was strongly enhanced by the combination with GO sheets. Increasing GO content led to significant enhancement in film transmittance and MB adsorptivity. In the aspect of the self-cleaning activity for MB, the addition of GO up to 1 wt.% showed higher efficiency but excess content led to similar performance in comparison with pure TiO2 film.