Controlled synthesis of uniform BiVO4 microcolumns and advanced visible-light-driven photocatalytic activity for the degradation of metronidazole-contained wastewater

Well-defined, uniform bismuth vanadate (BiVO₄) microcolumns were synthesized through a refined hydrothermal route. During the fabrication process, a detailed orthogonal design on the synthetic conditions was performed, aiming to optimize the experimental parameters to produce BiVO₄ materials (BiVO₄ (Opt.)) with the most prominent visible-light-driven photocatalytic efficiency, where the catalytic activities of the synthesized materials were evaluated via the decolorization of methylene blue under visible light irradiation. The BiVO₄ (Opt.) were then targetedly produced according to the determined optimal conditions and well characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, ultraviolet and visible diffuse-reflectance spectroscopy and photoluminescence spectroscopy. Compared with the commercial P25-TiO₂ photocatalysts, the as-synthesized BiVO₄ (Opt.) displayed superior visible-light-driven photocatalytic activities for the degradation of metronidazole-contained wastewater with the presence of H₂O₂. The degradation efficiency of metronidazole reached up to 70 % within 180 min, leading to a brief speculation on the possibly major steps of the visible-light-driven photocatalytic process. The current study provides a distinctive route to design novel shaped BiVO₄ architectures with advanced photocatalytic capacities for the treatment of organic pollutants in the aqueous environment.