Nanosized composite ZnO/TiO2 thin films for photocatalytic applications

This study is focused on preparation, characterization and photocatalysis with ZnO, TiO2 and nanocomposite thin films of ZnO/TiO2, prepared by spin coating method from suspensions of the commercial metal oxide powders in ethanol, with addition of PEG as stabilizer. The content of ZnO in the composite samples is selected to be 90%. The phase composition and morphology of the ZnO, TiO2 and mixed composite thin films of ZnO/TiO2 is characterized by X-Ray Diffraction and SEM analysis. The photocatalytic efficiency of the prepared films is tested in photooxidation of organic azo dye Orange II from aqueous solutions under irradiation with UV and visible light. The influence of the number of coated layers on the efficiency of dye photodegradation is also investigated. Comparative photocatalytic experiments with ZnO and TiO2 films are performed. It is found out that the nanocomposite film of 90% ZnO content with 3 coated layers manifests the highest photocatalytic efficiency under UV irradiation.