Electrochemical Cell Designs for Efficient Carbon Dioxide Reduction and Water Electrolysis: Status and Perspectives

Integrating renewable electricity and concentrated CO₂ from direct air capture, electrochemical CO₂ reduction reactions (eCO₂RR) offer a promising pathway for converting CO₂ into fuel chemicals, enabling the closure of the carbon loop in a sustainable manner. The clean H₂ produced via the hydrogen evolution reaction (HER) during water electrolysis can replace traditional fossil fuels without additional CO₂ emissions. Achieving large-scale and high-efficiency eCO₂RR and HER requires the development of rational electrolyzer designs, which are crucial for industrial implementation. This review examines recent innovations in system designs for eCO₂RR, HER, and the latest advances in in situ cell designs for operando characterization during electrochemical reactions. It focuses on cell improvements in flow patterns, membrane electrode assemblies, and electrolyte engineering to maximize catalytic activities at the industrial level. Besides, the review discusses optimizing counter-anodic reactions to improve the energy efficiency of eCO₂RR and water electrolysis, offering insights into the design of catalytic systems with efficient energy utilization. Furthermore, it explores the integration of eCO₂RR and HER with other electrochemical systems (e.g., fuel cells), highlighting their potential role in the decarbonization of future industrial processes. Finally, the summary, challenge, and outlook on the industrial-scale eCO₂RR and water electrolysis system designs are concluded.