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

Challenges in CO capture, CO crossover, product separation, and electrolyte recovery hinder electrocatalytic CO reduction (COR). 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 COR 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, recovers KOH with a 94.0% K yield, and achieves an 86.2% separation efficiency for COR products. The recovered KOH can capture CO from air or flue gas or be utilized as a COR electrolyte, closing the CO 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.