Electrochemical reactive carbon capture (eRCC) is a promising route for carbon utilization, but its performance is limited by fundamental constraints in conventional membrane electrode assembly (MEA) configurations. The key steps of eRCC, such as CO2 desorption, mass transport, and conversion, are detrimentally coupled at the zero-gap MEA interface. Here, we demonstrate that incorporating a dedicated stripping compartment enables the direct supply of CO2-laden solution to the membrane interface without electrode obstruction, and effectively decouples the mass transport of desorbed CO2 from its conversion in an interface-modulated three-compartment flow cell (3CFC), by modulating the pressure differential across compartments to drive directed CO2 transport. The in situ/operando Raman spectroscopy revealed its unique pH-buffering capability near the electrode, contributing to high C2+ selectivity and enhanced eRCC performance. This unique platform achieves remarkable stability and selectivity in the direct conversion of bicarbonate across diverse catalysts. At -200 mA/cm2, a Cu(OH)2-derived catalyst achieved an unprecedented C2+ selectivity of 52.0%, representing a 17-fold increase from 3.1% in the MEA cell. Moreover, Ag electrodes exhibit long-term stability for more than 155 h at -100 mA/cm2 from bicarbonate conversion, in contrast to the rapid increase in H2 observed in the MEA configuration. The CO selectivity of a Ni single-atom-catalyst from eRCC was dramatically enhanced to 96.7% utilizing 3CFC, compared to 38.0% in the MEA cell. This work presents a new principle for controlling the interfacial chemical environment in complex electrochemical systems.
Bak et al. (Thu,) studied this question.