Proton Pool for the Mitigation of Salt Precipitate Enhancing CO2 Electroreduction in a Flow Cell

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Flow cells featuring a gas diffusion electrode (GDE) have emerged as an attractive platform for electrochemical CO2 reduction, offering high current densities (~300 mA·cm−2) and low energy consumption. However, the formation of salt precipitates, particularly carbonate and bicarbonate, poses a significant deficiency by reducing the cell’s operational longevity. In this study, we present a novel approach to mitigate salt precipitates in real-time through acid–base interaction. Recovery efficiency and partial current density of the cell were used to evaluate the capability of removing salt precipitates and the maintenance of CO2 reduction reactions (CO2RRs). It was suggested that the direct treatment of intermittent acid rinse recovers the performance of CO2RRs to a large extent (>97%), and the modification of the proton exchange resin reduces the reduction rate of partial current densities to 1/15 than that of the unmodified. This improvement enhances the cell’s catalytic performance, enabling the stability test for catalysts within the GDE-based flow cell.