Integrated system for electrolyte recovery, product separation, and CO2 capture in CO2 reduction

Challenges in CO 2 capture, CO 2 crossover, product separation, and electrolyte recovery hinder electrocatalytic CO 2 reduction (CO 2 R). Here, we present an integrated electrochemical recovery and separation system (ERSS) with an ion separation module (ISM) between the anode and cathode of a water electrolysis system. During ERSS operation, protons from the anolyte flow through the anodic cation exchange membrane (CEM) into the ISM, acidifying the CO 2 R effluent electrolyte. Cations like K + in the ISM flow through the cathodic CEM into the catholyte to balance the OH − ions from hydrogen evolution. ERSS recycles electrolyte-adsorbed CO 2 , recovers KOH with a 94.0% K + yield, and achieves an 86.2% separation efficiency for CO 2 R products. The recovered KOH can capture CO 2 from air or flue gas or be utilized as a CO 2 R electrolyte, closing the CO 2 capture, conversion, and utilization loop. Compared to the conventional acid-base neutralization process, ERSS saves $119.76 per ton of KOH recovered and is applicable to other aqueous alkaline electrosynthesis reactions. CO 2 capture, product separation, and electrolyte recovery are critical challenges in CO 2 electroreduction. Here, the authors present an electrochemical recovery-separation system that addresses these challenges and facilitates the application of CO 2 reduction technology.