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

Abstract A highly photocatalytic Au-TiO2 hybrid thin film was prepared by the photocatalytic deposition of Au nanoparticles (NPs) on reactive sputtered TiO2 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-TiO2 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 TiO2, which significantly reduces the photocatalytic performance.