Hydrated CO2-mediated redox chemistry for biophotoelectrocatalytic oxyfunctionalization of C–H bonds

Abstract

Biophotoelectrocatalysis provides chemo-, regio- and stereoselective routes to chemicals by coupling redox biocatalysis with photoelectrocatalysis. This biomimetic strategy, however, is limited by unwanted photoelectrocatalysis side reactions and the high cost of redox mediators. Here we report a sustainable biosolar platform that uses bicarbonate (HCO3−), a hydrated form of CO2, as a redox mediator to drive oxyfunctionalization of inert C–H bonds. Using molybdenum-doped bismuth vanadate as a model photoelectrode, we accelerate two-electron H2O oxidation for in situ H2O2 production and mitigate enzyme-damaging OH· generation via HCO3− photoredox chemistry. Photoelectrochemical and spectroscopic analyses revealed that HCO3− directs the H2O oxidation pathway towards H2O2 through the formation of a peroxycarbonate intermediate at the photoanode surface. The integration of HCO3− mediation with H2O2-dependent unspecific peroxygenase achieves an exceptional turnover of various enantioselective C–H oxyfunctionalization reactions under ambient conditions. The HCO3−-mediated H2O2 photosynthetic system opens up opportunities for sustainable oxygenative biosynthesis. (Figure presented.)