Preparation of titanium(IV) oxide thin film photocatalyst by sol–gel dip coating

Thin films of titanium dioxide (TiO2) were deposited on variety of substrates by a simple sol–gel dip coating technique. The substrates were coated with titanium peroxide precursor solution of controlled viscosity at a constant pulling rate of 1 mm s−1, air-dried and further heated at 400 °C to obtain uniform films with good adhesion to the substrate. The change in viscosity of the peroxide solution with time and the variation of film thickness with viscosity of the gel were studied to optimize the deposition parameters. Films of titanium oxide as well as the dried powder of bulk gel were characterized by different techniques like X-ray diffraction (XRD), UV–Vis, scanning electron microscopy (SEM), N2 adsorption and thermogravimetric differential thermal analysis (TG-DTA) techniques. The titanium oxide films deposited by this technique were 20–100 nm thick with a particle size of 4–10 nm and showed anatase structure. The titanium oxide films were found to be very active for photocatalytic decomposition of salicylic acid and methylene blue.