Synthesis and characterization of Ag doped TiO ₂ heterojunction films and their photocatalytic performances

In this study, undoped and silver (Ag) doped titanium dioxide (TiO ₂ ) films were successfully synthesized by sol-gel spin coating technique on the Si substrates. Photocatalytic activities of the TiO ₂ films with different Ag content were investigated for the degradation of methylene blue (MB) under UV light irradiation. The crystal phase structure, surface morphology, chemical and optical properties of Ag-doped TiO ₂ films were characterized using an X-ray diffractometer (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), UV–vis spectrophotometer, and FTIR spectrophotometer. The results showed that the Ag-doped TiO ₂ films calcined at 500 °C had the crystalline anatase phases and the surface morphologies with some cracks. Ag substitution into TiO ₂ matrix enhanced the photocatalytic activity of TiO ₂ films under UV light irradiation as compared to the undoped TiO ₂ film. Furthermore, the results indicated that the 0.7% Ag doped TiO ₂ film exhibited a superior photocatalytic activity than that of undoped and other Ag-doped TiO ₂ films. This study demonstrated the potential of an application of Ag doped films to efficiently treat dissolved organic contaminants in water.