Reactor operating parameters and their effects on the local reaction environment of CO(2) electroreduction

Abstract

Low temperature aqueous electrochemical CO₍₂₎ reduction (ECR) emerged as a pathway to close the carbon cycle with the integration of renewable energy. However, activity, selectivity, and stability barriers prevent ECR from entering industrial scale operation. While catalyst design has made meaningful progress towards selective and active production of many products including CO, formate, and ethylene, operating conditions during catalyst testing have not been standardized. Operational parameters drastically impact the local reaction environment of the ECR and thus the performance of ECR. Herein, we summarize the prevailing operational variability of ECR and their interconnectedness. We first analyze reactant availability via tuning of cell geometry and CO₍₂₎ pressures. Then, optimization towards electrolyzer components including electrolyte, electrodes, and bipolar plates is discussed. We further assess the electrochemical protocols to enhance the performance or accelerate the degradation of ECR and the considerations required to scale up ECR to pilot scale. Finally, we provide perspectives on the current challenges of ECR and their promising solutions.