Photoelectrochemical Epoxidation of Cyclohexene on an α-Fe₂O₃ Photoanode Using Water as the Oxygen Source

This study developed a safe and sustainable route for the epoxidation of cyclohexene using water as the source of oxygen at room temperature and ambient pressure. Here, we optimized the cyclohexene concentration, volume of solvent/water (CH3CN, H2O), time, and potential on the photoelectrochemical (PEC) cyclohexene oxidation reaction of the α-Fe2O3 photoanode. The α-Fe2O3 photoanode epoxidized cyclohexene to cyclohexene oxide with a 72.4 ± 3.6% yield and a 35.2 ± 1.6% Faradaic efficiency of 0.37 V vs Fc/Fc+ (0.8 VAg/AgCl) under 100 mW cm-2. Furthermore, the irradiation of light (PEC) decreased the applied voltage of the electrochemical cell oxidation process by 0.47 V. This work supplies an energy-saving and environment-benign approach for producing value-added chemicals coupled with solar fuel generation. Epoxidation with green solvents via PEC methods has a high potential for different oxidation reactions of value-added and fine chemicals.