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

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.