Ethylene Electrosynthesis via Selective CO2 Reduction: Fundamental Considerations, Strategies, and Challenges

Abstract The electrochemical carbon dioxide reduction reaction (CO 2 RR) is a promising approach for reducing atmospheric carbon dioxide (CO 2 ) emissions, allowing harmful CO 2 to be converted into more valuable carbon‐based products. On one hand, single carbon (C 1 ) products have been obtained with high efficiency and show great promise for industrial CO 2 capture. However, multi‐carbon (C 2+ ) products possess high market value and have demonstrated significant promise as potential products for CO 2 RR. Due to CO 2 RR's multiple pathways with similar equilibrium potentials, the extended reaction mechanisms necessary to form C 2+ products continue to reduce the overall selectivity of CO 2 ‐to‐C 2+ electroconversion. Meanwhile, CO 2 RR as a whole faces many challenges relating to system optimization, owing to an intolerance for low surface pH, systemic stability and utilization issues, and a competing side reaction in the form of the H 2 evolution reaction (HER). Ethylene (C 2 H 4 ) remains incredibly valuable within the chemical industry; however, the current established method for producing ethylene (steam cracking) contributes to the emission of CO 2 into the atmosphere. Thus, strategies to significantly increase the efficiency of this technology are essential. This review will discuss the vital factors influencing CO 2 RR in forming C 2 H 4 products and summarize the recent advancements in ethylene electrosynthesis.