Evaluation of Process Parameters for Integrated CO₂ Electrolysis to Produce Ethylene

Electrochemical CO₂ reduction provides a promising strategy for reducing greenhouse gas emissions by converting CO₂ into chemicals such as ethylene. Integrated CO₂ electrolysis, using CO₂-enriched absorbent solutions, is a cost-effective alternative to gas-fed systems due to reduced process complexity. However, for industrial applications, the process parameters need to be optimized to enhance selectivity and efficiency. Despite advances in catalyst and cell design, the impact of operational factors like catholyte flow rate, pressure, and temperature on C₂₊ product selectivity remains largely unexplored. This study systematically investigates the effects of catholyte flow rate, overpressure, and temperature on ethylene selectivity in integrated CO₂ electrolysis with a potassium carbonate absorbent. Our results show that increasing the catholyte flow rate enhances the Faraday efficiency for ethylene by mitigating mass transport limitations between the flow field and the catalyst layer, whereas increasing pressure or temperature does not yield similar improvements. This insight shifts the focus from stoichiometric availability of physically dissolved CO₂ to mass transport limitations, suggesting that further advances in cell design could unlock higher conversion efficiencies. Our study provides a foundation for scaling up integrated CO₂ electrolysis by highlighting the importance of improving mass transport, a key step toward industrial implementation of sustainable CO₂ conversion technologies.