Preparation and super-hydrophilic properties of TiO2/SnO2 composite thin films

SnO2–TiO2 composite thin films were fabricated on soda-lime glass with sol–gel technology. By measuring the contact angle of the film surface and the degradation of methyl orange, we studied the influence of SnO2 doping concentration, heat-treatment temperature and film thickness on the super-hydrophilicity and photocatalytic activity of the composite films. The results indicate that the doping of SnO2 into TiO2 can improve their hydrophilicity and photocatalytic activity, and the composite film with 1–5 mol% SnO2 and heat-treated at 450°C is of super-hydrophilicity. The optimal SnO2 concentration for the photocatalytic activity is 10 mol% and larger film thickness is helpful to reduce the contact angle of the composite films.