A novel Z-scheme Bi₂WO₆-based photocatalyst with enhanced dye degradation activity

To overcome the drawback caused by rapid recombination of photogenerated electron-hole pairs, a novel visible-light-driven Bi₂WO₆/r-GO/Bi₂₅FeO₄₀ Z-scheme photocatalyst was fabricated through the hydrothermal method. The as-prepared sample was analyzed by X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), electrochemical impedance spectra (EIS), and X-ray photoelectron spectrometer (XPS). At the same time, the photocatalytic performance of ternary material was estimated by degradation of methylene blue (MB) aqueous solution under visible-light irradiation. Bi₂WO₆/r-GO/Bi₂₅FeO₄₀ displayed a superior photocatalytic performance compared with pure Bi₂WO₆. A dye degradation rate of 98.1% was appeared in ternary material under a 30-min photocatalytic experiment. r-GO plays an important role in ternary material; it acted as a charge-transfer bridge to accelerate electron transfer from Bi₂WO₆ to Bi₂₅FeO₄₀. Therefore, the recombination of the photogenerated electron holes of the Bi₂WO₆ itself was effectively suppressed. Most important, the possible photocatalytic mechanism was evaluated on the basis of UV–vis and PL analysis. This work provides a new idea for the synthesis of new photocatalytic materials with enhanced photocatalytic properties.