Photocatalytic activity of Ag nanoparticle-dispersed N-TiO₂ nanofilms prepared by magnetron sputtering

Using magnetron sputtering, pure TiO₂ nanofilms and Ag/TiO₂ bilayer nanofilms doped with nitrogen were deposited on glass substrates. Heat treatment of the Ag/N-TiO₂ nanofilms at 400 °C led to the formation of Ag nanoparticles, which were dispersed inside the TiO₂ films as well as on the free surface of the TiO₂ films. The photocatalytic activity of the Ag/N-TiO₂ nanofilms with dispersed Ag nanoparticles was examined by UV-vis diffuse reflectance spectroscopy. The rate constants for the photodegradation of methylene blue (MB) in aqueous solutions of MB by N-TiO₂-based nanofilms are about one order larger than those for self-degradation or for pure TiO₂ nanofilms. The rate constants for the photodegradation of aqueous solutions of MB by the Ag/N-TiO₂ nanofilms are larger than those for the N-TiO₂ nanofilms. The Ag nanoparticles improve the photocatalytic activity of TiO₂ films, possibly through the surface plasmon absorption effect of Ag nanoparticles, which activates photo-generated charge carriers through the transfer of plasmonic energy.