Scalable and low-energy decoupled electrochemical CO2 capture

Abstract

Electrochemical CO2 capture with renewable electricity provides a promising avenue for efficient decarbonization but faces challenges by instability, discontinuity, high energy consumption, and difficulties in scale-up. Here, we first propose a scalable electrochemical CO2 capture strategy by separating the traditional single electrochemical redox reaction process into a stepwise electrochemical-chemical redox reaction process. Hydrogen evolution reaction and redox carrier oxidation reaction swings the pH of electrolyte at the cathode and anode to capture CO2 efficiently which avoids side effects through decoupling of electrochemical-swing for CO2 capture and redox carrier regeneration in different times and spatial domains. We demonstrate a stable electrochemical CO2 capture process over 200 hours with low energy consumption (49.15 kJ mol-1 CO2 at 10 mA cm-2). Furthermore, the system is tunable and modular. Molecular design can be used to tailor the potential and allow scalability across various process sizes, making it a promising strategy for large-scale decarbonization.