Sonochemical-Assisted Deposition Synthesis and Characterization of Metallic Au Nanoparticles Modified Thin Bi2WO6 Nanoplates for Enhanced Visible-Light-Driven Photocatalytic Reaction

Abstract

Au/Bi₂WO₆ nanocomposites as visible-light-driven photocatalyst were synthesized by a sonochemical-assisted deposition method and used for rhodamine B (RhB) degradation under visible light irradiation. Phase, morphology, surface area, atomic vibration, oxidation state of elements and optical properties of as-prepared Bi₂WO₆ and Au/Bi₂WO₆ were characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, Raman spectrophotometry, nitrogen adsorption–desorption isotherm, UV-Visible diffuse reflectance spectroscopy, Brunauer–Emmett–Teller surface area analysis and X-ray photoelectron spectroscopy. The results identified that metallic Au nanoparticles were supported on the surface of thin Bi₂WO₆ nanoplates to create heterostructure Au/Bi₂WO₆ nanocomposites. The Au/Bi₂WO₆ nanocomposites show strong absorption range of visible light in 450–700 nm. The heterostructure 5% Au/Bi₂WO₆ nanocomposites exhibited the photodegradation for RhB with excellent efficiency of 97.91% under visible light irradiation for 150 min due to the Schottky interface of Au nanoparticles and Bi₂WO₆ nanoplates and surface plasmon resonance (SPR) effect of metallic Au nanoparticles. The role of active species in degrading RhB over 5% Au/Bi₂WO₆ nanocomposites was investigated and a photocatalytic mechanism was proposed and explained according to the experimental results.