Bridging activity gaps between batch and flow reactor configurations in the electroreduction of carbon dioxide.

To date, the understanding of various modes of CO2 mass transport remains incomplete, impeding the transfer of catalysts identified in the more accessible electrochemical batch cells to high-performance flow cells. In this work, we demonstrate that the meniscus region formed between the electrode and the convex liquid level due to the electrowetting of the catalyst plays a vital role in the CO2RR in batch cells. CO2RR in the meniscus region in batch cells exhibits similar performance with that in flow cells, and the performance disparity between these two configurations largely disappears when conducting CO2RR primarily in the meniscus region. An assembled double-sided gas diffusion electrode with a gas channel is developed to maximize the meniscus-like region, achieving a CO2RR partial current density of 640 mA/cm2geo on commercial Cu in the KHCO3 electrolyte. This performance represents the highest CO2RR activity in neutral buffered media.