The effect of annealing on photocatalytic properties of nanostructured titanium dioxide thin films

The photocatalytic degradation of a non-biodegradable azo dye called (C.I. Direct 80, Red Sulphonyl 3BL) was investigated using TiO2 thin films in aqueous solution under irradiation of a mercury lamp Philips (UV-C) light source. The effect of operational parameters, i.e., annealing temperature of thin film, substrate nature on which TiO2 films were deposited, film thickness, pH of the solution, dye concentration, and irradiation time on the degradation rate of azo dye aqueous solutions was examined. Results show that the employment of efficient photocatalyst and the selection of optimal operational parameters lead to complete decolorization. The best conditions for maximum photocatalytic degradation were found to be pH I at 5 ppm concentration of dye over TiO2 thin films deposited on glass substrate coated with indium-tin oxide having 350 nm thicknesses annealed at 550 degrees C. The samples are all in the complete anatase phase and the particle size is in nanometer scale which is confirmed by XRD pattern analysis. (c) 2005 Elsevier Ltd. All rights reserved.