HClO-Mediated Photoelectrochemical Epoxidation of Alkenes with Near 100 % Conversion Rate and Selectivity by Regulating Lattice Chlorine Cycle.

Directional organic transformation via a green, sustainable catalytic reaction has attracted a lot of attention. Herein, we report a photoelectrochemical approach for highly selective epoxidation of alkenes in a salt solution using Co ₂ (OH) ₃ Cl (CoOCl) as a bridge of photo-generated charge, where the lattice Cl ^- of CoOCl can be oxidized to generate HClO by the photo-generated holes of BiVO ₄ photoanode and be spontaneously recovered by Cl ^- of a salt solution, which then oxidizes the alkenes into the corresponding epoxides. As a result, a series of water-soluble alkenes, including 4-vinylbenzenesulfonic acid sodium, 2-methyl-2-propene-1-sulfonic acid sodium, and 3-methyl-3-buten-1-ol can be epoxidized with near 100 % conversion rate and selectivity. Through further inserting a MoO _x protection layer between BiVO ₄ and CoOCl, the stability of CoOCl-MoO _x /BiVO ₄ can be maintained for at least 120 hours. This work opens an avenue for solar-driven organic epoxidation with a possibility of on-site reaction around the abundant ocean.
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