The Impact of CO2 Regeneration Positions on Electrochemical CO2 Reduction

Abstract

Implementing electrochemical CO₂ reduction can decarbonize practical chemical and fuel production. However, in a typical CO₂ electrolyzer, electrochemical CO₂ capture (i.e., CO₂ reacts with electrochemically produced OH⁻ to form (bi)carbonates that are subsequently regenerated to CO₂ by the H⁺ flux in the reactor) commences in parallel with its electroreduction. Such a phenomenon is observed in various electrolyzer configurations with different electrolyte compositions. This concept begins with a brief discussion on how CO₂ capture occurs in CO₂ electrolyzers and focuses on the impact of CO₂ regeneration locations, including the anode, the electrolyte, and the ion-exchange membrane, on CO₂ electrolysis performance. It is shown that the key to overcoming the low CO₂ utilization and operational lifetime is positioning CO₂ regeneration on ion-exchange membranes. The goal is to highlight the essential role of the ion flow management approach in designing high-performance CO₂ electrolyzers. It would contribute to commercializing CO₂ electrolyzers for carbon-neutral chemical synthesis.