Understanding Mass Transport and Reaction Environment to Optimize CO₂ Electrodialysis Systems

Although previous studies have significantly advanced CO₂ ED at the process, membrane, and system levels, the coupled mass transport and reaction environment governing CO₂ regeneration remain insufficiently understood, limiting further improvement in current efficiency.

Here we develop a spatially resolved modeling framework for CO₂ ED. Our approach captures the interplay among concentration polarization, pH gradient, and reaction localization, thereby enabling direct prediction of CO₂ generation rate, proton utilization efficiency, and bubble nucleation barrier. Using three representative electrolytes with distinct acid–base properties, we show that buffering and acidity can substantially reshape ion distributions and reaction zones, which produce electrolyte-specific trade-offs between CO₂ regeneration and bubble nucleation.