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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 (CH 3 CN, H 2 O), time, and potential on the photoelectrochemical (PEC) cyclohexene oxidation reaction of the α-Fe 2 O 3 photoanode. The α-Fe 2 O 3 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 V Ag/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.

In this study, a facile approach has been successfully applied to synthesize a W-doped Fe 2 O 3 /MoS 2 core-shell electrode with unique nanostructure modifications for photoelectrochemical performance. A two-dimensional (2D) structure of molybdenum disulfide (MoS 2 ) and tungsten (W)-doped hematite (W:α-Fe 2 O 3 ) overcomes the drawbacks of the α-Fe 2 O 3 and MoS 2 semiconductor through simple and facile processes to improve the photoelectrochemical (PEC) performance. The highest photocurrent density of the 0.5W:α-Fe 2 O 3 /MoS 2 photoanode is 1.83 mA·cm -2 at 1.23 V vs reversible hydrogen electrode (RHE) under 100 mW·cm 2 illumination, which is higher than those of 0.5W:α-Fe 2 O 3 and pure α-Fe 2 O 3 electrodes. The overall water splitting was evaluated by measuring the H 2 and O 2 evolution, which after 2 h of irradiation for 0.5W:α-Fe 2 O 3 /MoS 2 was determined to be 49 and 23.8 μmol.cm -2 , respectively. The optimized combination of the heterojunction and metal doping on pure α-Fe 2 O 3 (0.5W:α-Fe 2 O 3 /MoS 2 photoanode) showed an incident photon-to-electron conversion efficiency (IPCE) of 37% and an applied bias photon-to-current efficiency (ABPE) of 26%, which are around 5.2 and 13 times higher than those of 0.5W:α-Fe 2 O 3 , respectively. Moreover, the facile fabrication strategy can be easily extended to design other oxide/carbon-sulfide/oxide core-shell materials for extensive applications.