How to Select Each Component of CO₂ Electrolyzers

Electrochemical CO₂ electrolyzers are increasingly recognized for their potential to convert CO₂ into valuable chemical feedstocks, addressing critical environmental and economic challenges. Traditionally, the catalytic properties of the cathode, where CO₂RR directly occurs, have been the main focus of research due to their control over product selectivity. More recently, however, membrane-based electrolyzers-commonly used in fuel cells and water electrolyzers-have shown substantial potential for commercial CO₂ reduction, offering improved scalability and efficiency. Nevertheless, the complex components in membrane-based electrolyzers require precise optimization, as each unit directly impacts system performance and product selectivity. In this review, the structures and components of membrane-based CO₂ electrolyzers are systematically examined, including the electrolyzer design, flow channels, membranes, electrolytes, CO₂ supply units, and electrodes. Recent innovations in the optimization of these components are highlighted to provide insights into advancing CO₂RR technology toward commercially feasible applications. This approach can assist considerably in improving the CO₂RR electrolyzer performance, thereby helping predict optimal pathways for commercial realization and guide future development.