Plasmonic and non-plasmonic contributions on photocatalytic activity of Au-TiO2 thin film under mixed UV–visible light.

A highly photocatalytic Au-TiO 2 hybrid thin film was prepared by the photocatalytic deposition of Au nanoparticles (NPs) on reactive sputtered TiO 2 thin film. By altering the ratio of the visible (Vis) and ultra-violet (UV) light (Vis/UV), we investigated plasmonic and non-plasmonic contributions of Au NPs to the overall photocatalytic activity. While, a gradual increase of Vis/UV (≤0.24/1) led to a steady enhancement of the photocatalytic performance of Au-TiO 2 hybrid structures, further increase in Vis/UV (≥0.30/1) did not foster the enhancement further. At high Vis/UV, plasmon excited electrons seem to start promoting electron-hole recombination in TiO 2 , which significantly reduces the photocatalytic performance. Unlabelled Image • A highly active TiO 2 film allows the deposition of Au nanostructures under low intensity UV light • Au nanostructures lead to both plasmonic and non-plasmonic contributions on TiO 2 • Au-TiO 2 photocatalyst exhibits an enhanced absorption in the visible region • Vis/UV light ratio governs the photocatalytic performance of Au-TiO 2 hybrid structures [ABSTRACT FROM AUTHOR]