Enhanced photocatalytic activity of Ag–TiO2/Ag heterogeneous films

Ag-deposited TiO2 and Ag (Ag–TiO2/Ag) films coated on glass substrates were prepared using a simple sol-gel and dip-coating method. The Ag chemical state was investigated through X-ray diffractometry and X-ray photoelectron spectroscopy. Results showed that the Ag mainly exists in metallic state in the Ag–TiO2 film. Ag–TiO2/Ag exhibits higher photocatalytic activity than individual Ag–TiO2 and TiO2/Ag films. This enhanced photocatalytic activity was attributed to high surface plasmon resonance effects and separation rates of photoinduced electron-hole pairs of Ag nanoparticles. Results were verified by photoluminescence and UV–Vis spectroscopy.