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

Abstract

The electrochemical carbon dioxide reduction reaction (CO2RR) is a promising approach for reducing atmospheric carbon dioxide (CO2) emissions, allowing harmful CO2 to be converted into more valuable carbon‐based products. On one hand, single carbon (C1) products have been obtained with high efficiency and show great promise for industrial CO2 capture. However, multi‐carbon (C2+) products possess high market value and have demonstrated significant promise as potential products for CO2RR. Due to CO2RR's multiple pathways with similar equilibrium potentials, the extended reaction mechanisms necessary to form C2+ products continue to reduce the overall selectivity of CO2‐to‐C2+ electroconversion. Meanwhile, CO2RR 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 H2 evolution reaction (HER). Ethylene (C2H4) remains incredibly valuable within the chemical industry; however, the current established method for producing ethylene (steam cracking) contributes to the emission of CO2 into the atmosphere. Thus, strategies to significantly increase the efficiency of this technology are essential. This review will discuss the vital factors influencing CO2RR in forming C2H4 products and summarize the recent advancements in ethylene electrosynthesis.