Progress and Understanding of CO₂/CO Electroreduction in Flow Electrolyzers

The electroreduction of CO2 and CO into valuable chemicals and fuels powered by renewable electricity can tackle anthropogenic carbon emissions and close the carbon cycle. However, both CO2 and CO have low solubility in aqueous electrolytes, affording their sluggish mass transport across the electrolyte. CO2/CO electroreduction in a flow electrolyzer can tackle this problem by directly delivering the gaseous reactant to the electrode surface. Significant progress has been made recently in simultaneously obtaining high reaction rates and high product selectivity using flow cell configurations. This perspective highlights how different flow cell designs impact CO2/CO electroreduction and outlines potential strategies that may further improve the cell performance. The challenges and opportunities related to fundamental and engineering aspects are also discussed.