Bias-Free In Situ H2O2 Generation in a Photovoltaic-Photoelectrochemical Tandem Cell for Biocatalytic Oxyfunctionalization

Peroxygenases catalyze selective oxyfunctionalization of hydrocarbons with high conversion efficiencies using H2O2 as a key cosubstrate. Here, we report an unbiased photo electrochemical (PEC) tandem structure consisting of a FeOOH/BiVO4 photoanode, a Cu(In,Ga)Se-2 solar absorber, and a graphitic carbon nitride/reduced graphene oxide hybrid cathode for light-driven peroxygenase catalysis. Powered by sufficient photovoltage generated by the solar absorber, the PEC platform generates H2O2 in situ through reductive activation of molecular oxygen using water as an electron donor in the absence of external bias. The peroxygenase from Agrocybe aegerita catalyzed the stereoselective hydroxylation of ethylbenzene to (R)-1-phenylethanol with total turnover numbers and high enantioselectivity (ee > 99%) in the unbiased PEC tandem system.