Valorizing carbon dioxide via electrochemical reduction on gas‐diffusion electrodes

The electrochemical carbon dioxide (CO2) reduction provides a means to upgrade CO2 into value‐added chemicals. When powered by renewable electricity, CO2 electroreduction holds the promise of chemical manufacturing with carbon neutrality. A commercially relevant CO2 electroreduction process should be highly selective and productive toward desired products, energetically efficient for power conversion, and stable for long‐term operation. To achieve these goals, designing gas‐diffusion catalytic electrodes and prototyping reactors built upon in‐depth understandings of the reaction mechanisms are of paramount importance. In this review, the fundamentals of gas‐diffusion electrodes are briefly presented. Then, the most recent advances in developing high‐performance CO2 reduction using gas‐diffusion electrodes are overviewed. Reactor engineering aiming at enhancing productivity, energy efficiency, CO2 single‐pass utilization, and operating lifetime is further discussed. Challenges in developing CO2 electroreduction systems are included. The prospects for advancing CO2 electroreduction toward practical applications are also narrated. This review overviews the most recent progress of CO2 electroreduction using gas‐diffusion electrodes. The fundamentals of gas‐diffusion electrodes were first elucidated. Achievements in commercially relevant gas‐diffusion‐electrode‐based CO2 electroreduction were then summarized. Newly emerged reactor designs were introduced. Challenges and the future of CO2 electroreduction were discussed, of which the focus covers the carbonate issue and energy consumption.