Electroenzymatic CO2 Fixation Using Redox Polymer/Enzyme-Modified Gas Diffusion Electrodes

We describe the fabrication of gas diffusion electrodes modified with polymer/enzyme layers for electroenzymatic CO2 fixation. For this, a metal-free organic low-potential viologen-modified polymer has been synthesized that reveals a redox potential of around −0.39 V vs SHE and is thus able to electrically wire W-dependent formate dehydrogenase from Desulfovibrio vulgaris Hildenborough, which reversibly catalyzes the conversion of CO2 to formate. The use of gas diffusion electrodes eliminates limitations arising from slow mass transport when solid carbonate is used as CO2 source. The electrodes showed satisfactory stability that allowed for their long-term electrolysis application for electroenzymatic formate production.