Surface Engineered BiVO₄ for Photoelectrochemical Alkene Epoxidation via Bromine Mediation

Selective epoxidation of alkenes is essential in organic synthesis, yet achieving it under mild conditions presents significant challenges. Photoelectrochemical (PEC) alkene epoxidation driven by hypobromite (BrO–, Br+) formation offers a green and sustainable route, and enhancing Br+ production is essential for achieving high product selectivity. A synergistic strategy that integrates water oxidation to hydrogen peroxide with bromide oxidation to bromine (Br2) using a surface engineered BiVO4 photoanode is presented. In situ generated H2O2 and Br2 yield BrO–, which serves as an active brominating (Br+) agent for alkene epoxidation. Consequently, the surface engineered BiVO4 photoanode achieves over 98.1 ± 0.79% conversion rate and 91.9 ± 0.99% selectivity across various alkenes. An unbiased PEC tandem device is constructed by coupling a BiVO4 photoanode for styrene epoxidation with a Cu2O photocathode for hydrogen production, achieving simultaneous styrene oxide production with 86.4% selectivity and hydrogen production. Our work provides new insights into PEC organic synthesis and hydrogen production.