Experimental and theoretical investigation on photocatalytic activities of 1D Ag/Ag 2 WO 4 nanostructures

Ag 2 WO 4 is a significant photocatalyst that responds to UV light irradiation only, which greatly hinders it for further practical application for solar light. To address this problem, herein, 1D plasmonic Ag/Ag 2 WO 4 photocatalysts have been fabricated by a successive process including hydrothermal synthesis to obtain Ag 2 WO 4 followed by an additional in situ chemical-reduction process for Ag decoration. Then, the structural features, optical properties, and electronic structures of Ag 2 WO 4 and Ag/Ag 2 WO 4 nanowires were systematically investigated via a combination of theoretical calculations and experimental evidence. The plasmon-enhanced Ag/Ag 2 WO 4 nanowires exhibited higher visible-light-driven photocatalytic activity, which performed a desired photodestruction ratio of 91.2% on methylene blue within 60 min and good stability in five cycles. The Ag decoration greatly facilitates visible-light harvesting and thus promotes photogenerated radical oxidation to dye, which is evidenced by the higher hydroxyl radical level of Ag/Ag 2 WO 4 detected in the ESR test during the photocatalytic process. The theoretical calculation based on density functional theory indicates that Ag nanoparticles formed on the surface of Ag 2 WO 4 could narrow the band gap of Ag 2 WO 4 . In addition, the surface plasmon resonance absorption effect and fast charge transfer effect in the metal-semiconductor system contribute to the photocatalytic performance of Ag/Ag 2 WO 4 .