Advances in Reactive Carbon Capture via Carbonate/Bicarbonate Electrolysis for Efficient CO2 Utilization

Abstract

Electrochemical reduction of carbon dioxide (CO₂RR) offers a crucial pathway for converting CO₂ into value-added chemicals. Despite significant progress in catalyst and electrolyzer development, the practical application of CO₂RR remains hampered by challenges stemming from limited CO₂ conversion efficiency by carbonate (CO₃²⁻) and bicarbonate (HCO₃⁻) formation. Reactive carbon capture (RCC) integrates CO₂ capture and electrochemical conversion, directly utilizing CO₃²⁻/HCO₃⁻-containing solution as both the carbon source and the electrolyte. This approach avoids the energy penalties of conventional CO₂ purification and regeneration. This review focuses on recent advances in RCC electrolysis, particularly electrolyzers based on bipolar membrane (BPM) and cation-exchange membrane (CEM) configurations. We discuss how tailored catalyst design, electrode architecture, and microenvironment can enhance product selectivity and efficiency. Significant challenge for BPM-based systems is the high overpotential associated with water dissociation (WD), which can be mitigated by integrating WD catalysts. For CEM-based systems, precise control over the pH gradient through porous interlayers is essential to balance proton (H⁺) supply and facilitate in-situ CO₂ generation while suppressing the hydrogen evolution reaction (HER). Finally, we address the critical challenges of flue gas impurities (SO_x, NO_x) and present innovative interfacial engineering strategies designed to enhance CO₃²⁻/HCO₃⁻ activity and selectivity, thereby paving the way for the robust and scalable implementation of RCC technologies.