Coupling Plasmonic and Cocatalyst Nanoparticles on N⁻TiO₂ for Visible-Light-Driven Catalytic Organic Synthesis

The use of the surface plasmon resonance (SPR) effect of plasmonic metal nanocomposites to promote photocarrier generation is a strongly emerging field for improving the catalytic performance under visible-light irradiation. In this study, a novel plasmonic photocatalyst, AuPt/N⁻TiO₂, was prepared via a photo-deposition⁻calcination technique. The Au nanoparticles (NPs) were used herein to harvest visible-light energy via the SPR effect, and Pt NPs were employed as a cocatalyst for trapping the energetic electrons from the semiconductor, leading to a high solar-energy conversion efficiency. The Au₂Pt₂/N⁻TiO₂ catalyst, herein with the irradiation wavelength in the range 460⁻800 nm, exhibited a reaction rate ~24 times greater than that of TiO₂, and the apparent quantum yield at 500 nm reached 5.86%, indicative of the successful functionalization of N⁻TiO₂ by the integration of Au plasmonic NPs and the Pt cocatalyst. Also, we investigated the effects of two parameters, light source intensity and wavelength, in photocatalytic reactions. It is indicated that the as-prepared AuPt/N⁻TiO₂ photocatalyst can cause selective oxidation of benzyl alcohol under visible-light irradiation with a markedly enhanced selectivity and yield.