Chlorine radical-mediated electrochemical propylene epoxidation from seawater

Electrocatalytic chlorine-mediated propylene oxidation utilizing seawater represents a promising route for sustainable propylene oxide (PO) synthesis. Unfortunately, inefficient utilization of active chlorine species results in compromised yield and Faradaic efficiency (F.E.). Herein, we achieve efficient chlorine radical-mediated propylene to PO by incorporating Li into Co₃O₄, attaining a PO F.E. approaching 99.0% and a yield of 20.6 mol/m²/h in simulated seawater with long-term stability for over 100 h. Furthermore, a PO yield of 78.9 mol/m²/h is obtained even under an industrial-level current density of 0.5 A cm⁻², demonstrating competitive performance compared with most reported noble metal catalysts. Mechanistic investigations reveal that Li doping transforms the adsorption configuration of Cl⁻ on Co₃O₄ from linear Co-Cl structure to more favorable triangular Li-Cl-O configuration, thereby enhancing •Cl generation, and consequently redirecting propylene oxidation from conventional HClO pathway to a more efficient •Cl route. This work advances the mechanistic understanding of the mechanism of electrocatalytic propylene oxidation and offers great opportunities for the sustainable synthesis of commercial chemicals using waste lithium-ion batteries, seawater, and renewable electricity.