Electrolytic conversion of carbon capture solutions containing carbonic anhydrase

The electrolysis of carbon capture solutions bypasses energy-intensive CO₂ recovery steps that are often required to convert CO₂ into value-added products. We report herein an electrochemical flow reactor that converts carbon capture solutions containing carbonic anhydrase enzymes into carbon-based products. Carbonic anhydrase enzymes benefit CO₂ capture by increasing the rate of reaction between CO₂ and weakly alkaline solutions by 20-fold. In this study, we reduced CO₂-enriched bicarbonate solutions containing carbonic anhydrase ("enzymatic CO₂ capture solutions") into CO at current densities of 100 mA cm^-2. This result demonstrated how to electrolyse enzymatic CO₂ capture solutions, but the selectivity for CO production was two-thirds less than bicarbonate solutions without carbonic anhydrase. This reduction in performance occurred because carbonic anhydrase deactivated the catalyst surface. A carbon microporous layer was found to suppress this deactivation.