Research on WO₃/BiVO₄@FTO composite as an efficient catalyst for organic pollutant degradation, including its...

This study aims to develop a highly efficient photoelectrocatalytic material for the degradation of the organic pollutant rhodamine B (RhB). We successfully fabricated a WO₃/BiVO₄@FTO composite material using a simple electrodeposition technique. Material characterization revealed that WO₃ nanosheets are layered on top of coral-like BiVO₄ particles, forming a tightly-bound heterojunction. Optical performance tests showed that the introduction of WO₃ significantly enhanced the material's visible light absorption and slightly reduced its band gap (from 2.52 eV for BiVO₄ to 2.50 eV for WO₃/BiVO₄). More importantly, steady-state/transient fluorescence spectroscopy and EIS tests confirmed that this composite structure effectively promotes the separation of photogenerated electron-hole pairs and reduces charge transfer resistance. Under optimal conditions of 100 mW cm^-2 light intensity and a 1.5 V vs. RHE bias potential, the WO₃/BiVO₄@FTO photoanode achieved over 99% degradation of 10 mg L^-1 rhodamine B within 120 minutes. Active species trapping experiments indicated that hydroxyl radicals (˙OH) and photogenerated holes (h⁺) are the primary active species responsible for the degradation. Furthermore, the loading of WO₃ significantly improved the stability of the composite photoanode compared to the single BiVO₄ material. This research provides a new approach for preparing highly efficient and stable photoelectrocatalysts using the electrodeposition method.