Development of Ag-coated BiVO₄ nano/heterostructures for visible-light-responsive photocatalytic performance

Synthesis of Ag-coated BiVO4 nano/heterostructured photocatalysts was carried out through a two-step process, and their performance was comprehensively evaluated, in this study. The as-synthesized photocatalysts were characterized by X-ray diffraction (XRD), Fourier transfer infrared spectroscopy (FT-IR), Raman spectroscopy, transmission electron microscopy (TEM), field-emission scanning electron microscopy (FESEM), energy-dispersive spectroscopy (EDS), and UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS). Ag nanoparticles were successfully coated on walnut-like BiVO4 microarchitectures assembled from sphere-shaped nanostructures. Based on the optical results, Ag coating could effectively promote visible light absorption and greatly increase the light absorption threshold because of the synergistic effect on the surface plasmon resonance (SPR). Evaluations of nano/heterostructures' photo-reactivity were conducted by photodegradation of methylene blue (MB) in an aqueous environment subject to visible light irradiation (VLI). All Ag-BiVO4 nano/heterostructured samples showed improved photocatalytic efficiencies compared to Pure-BiVO4 sample, as approved by optical absorption studies. The Schottky scheme mechanism, which introduced a charge transfer route at the metal-semiconductor interface, was also discussed for photocatalytic reactions.