Abstract
Ag-TiO 2 nanostructured thin films with silver volume fraction of 0–40% were prepared by RF magnetron sputtering. The microstructure, surface topography, and optical properties of the films were characterized by X-ray diffractometer, transmission electron microscope, and ultraviolet–visible spectrophotometer. Photocatalytic activity of the films was evaluated by light-induced degradation of methyl orange (C 14H 14N 3NaO 3S) solution using a high pressure mercury lamp as lamp-house. The relation of photocatalytic activity and silver content was studied in detail. It is found that silver content influences microstructure of TiO 2 thin films, and silver in the films is metallic Ag (Ag 0). Photocatalytic activity of the films increases with increasing silver content up to 5 vol.% Ag and then decreases to values significantly still bigger than that of pure TiO 2 thin films. Silver nanoparticles significantly enhance the photocatalytic activity of TiO 2 films. The better separation between electrons and holes on silver modified TiO 2 thin films surface allowed more efficiency for the oxidation and reduction reactions. The enhanced photocatalytic activity was mainly attributed to the decrease of energy gap of the films and the increase of oxygen anion radicals O 2 − and reactive center of surface Ti 3+ on silver modified TiO 2 thin films surface.
Published Version
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