Silver decorated titanate/titania nanostructures for efficient solar driven photocatalysis

Photocatalysis has attracted significant interest to solve both the energy crisis and effectively combat environmental contamination. However, as the most widely used photocatalyst, titania (TiO2) suffers from inefficient utilization of solar energy due to its wide band gap. In the present paper, we describe a method to extend the absorption edge of photocatalyst to visible region by the surface plasmon effect of silver. Silver ions are photo-reduced onto the surface of titanate nanotubes, which are synthesized by a conventional hydrothermal method. The as-synthesized Ag/titanate composite is transformed into Ag/titania nanoparticles by annealing at different temperatures. It is found that the interaction of Ag nanoparticles with the supports (titanate/titania) plays a key role for the visible light activity. The samples annealed at low temperature (<350 °C) do not show significant activity under our conditions, while the one annealed at 450 °C shows fast-degradation of methyl orange (MO) under visible light irradiation. The detailed mechanisms are also discussed.

Silver nanoparticles decorated titanate/titania as visible light active photocatalysts: silver nanoparticles could be excited by visible light due to its surface plasmon effect and excited electrons could be transferred to the conduction band of the semiconductor, where the reduction process occurs.Figure optionsDownload as PowerPoint slideHighlights
► Uniform Ag nanoparticles are photo-reduced onto titanate and titania nanostructures.
► Titania crystal is formed by annealing hydrogen titanate at different temperatures.
► Best visible-light activity is achieved by Ag-loaded titania annealed at 450 °C.
► The visible light activity is attributed to the surface plasmonic resonance effect.