Preparation of Cr-doped TiO2 thin film by sonochemical/CVD method and its visible light photocatalytic activity for degradation of paraoxon

In this work, nanostructured TiO2 and Cr-doped TiO2 thin films were deposited on glass substrate through sonochemical-chemical vapor deposition (CVD) method. The resulting thin films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-visible absorption spectroscopy, and photoluminescence spectroscopy techniques. The TiO2 thin film has nanocubic morphology and the Cr-doped TiO2 thin film contains nanostructures with irregular shapes in its structures which these nanostructures themselves are composed from nanorods. Presence of Cr ions in the structure of TiO2 resulted in a decrease in the band gap energy of TiO2 and also in the reduction of photogenerated electron-hole recombination rate. The visible light photocatalytic activity of the prepared thin films were also investigated for degradation of paraoxon pesticide. According to the obtained results, the Cr-doped TiO2 thin film has higher photocatalytic activity than undoped TiO2 thin film. Moreover, in comparison with the undoped TiO2 thin film, the Cr-doped TiO2 thin film has higher stability.