A direct coupled electrochemical system for capture and conversion of CO2 from oceanwater

Capture and conversion of CO2 from oceanwater can lead to net-negative emissions and can provide carbon source for synthetic fuels and chemical feedstocks at the gigaton per year scale. Here, we report a direct coupled, proof-of-concept electrochemical system that uses a bipolar membrane electrodialysis (BPMED) cell and a vapor-fed CO2 reduction (CO2R) cell to capture and convert CO2 from oceanwater. The BPMED cell replaces the commonly used water-splitting reaction with one-electron, reversible redox couples at the electrodes and demonstrates the ability to capture CO2 at an electrochemical energy consumption of 155.4kJmol(-1) or 0.98 kWh kg(-1) of CO2 and a CO2 capture efficiency of 71%. The direct coupled, vapor-fed CO2R cell yields a total Faradaic efficiency of up to 95% for electrochemical CO2 reduction to CO. The proof-of-concept system provides a unique technological pathway for CO2 capture and conversion from oceanwater with only electrochemical processes. Isolating CO2 to use in electrochemical CO2 reduction systems is an ongoing issue. Here, the authors present a proof-of-concept integrated system combining a bipolar membrane electrodialysis cell with a vapor-fed CO2 reduction cell for capture and conversion of CO2 from oceanwater.