Nanocomposite thin films of TiO2/WO3 are prepared by the sol–gel method on glass substrates using a dip-coating technique. The initial precursors of composite sols are chloride salts of the respective metals dissolved in ethanol with the addition of hydrogen peroxide as a catalyst of the hydrolysis and sol stabilization. The WO3 content in the films is selected to be 5 or 10%. The film thickness is controlled by the number of coating cycles. The films are dried between the successive coatings and finally annealed at 520 °C in air for 2 h. The morphology and phase composition of the composite films is characterized by SEM/EDX and X-ray analysis. The photocatalytic action of the films is tested with respect to the degradation of malachite green in water solutions under UV and visible light irradiation. The composite films TiO2/WO3 with 10% of WO3 always exhibit a better photocatalytic activity than the pure TiO2 films even under strong visible light.
Fujishima, A, Zhang, X, Truck, D (2007) Int J Hydrogen Energy. 32:2664.