Light‐Driven Highly Selective Conversion of CO₂ to Formate by Electrosynthesized Enzyme/Cofactor Thin Film Electrode

The highly selective electrochemical reduction of carbon dioxide (CO₂) is reported to formate (HCOO^‐) at a compactly integrated bioelectrode. The enzymatic biocatalytic cathode is fabricated by single‐step electropolymerization of a multifunctional polydopamine film in which enzyme/cofactor couples are uniquely embedded. Interestingly, this thin biohybrid system of nanoscale thickness assures unprecedentedly prolonged catalytic enzyme stability for about two weeks. Mimicking the natural photosynthesis, combination with the photoanode utilizing the water oxidation, steadily produces formate at a faradaic efficiency of 99.18 ± 6.77% with little degradation at least for 1 d under 1 sun illumination and no external bias.