Carbon monoxide electrolysis has previously been reported to yield enhanced multi-carbon (C₂₊) Faradaic efficiencies of up to ~55%, but only at low reaction rates. This is due to the low solubility of CO in aqueous electrolytes and operation in batch-type reactors. Here, we present a high-performance CO flow electrolyser with a well controlled electrode–electrolyte interface that can reach total current densities of up to 1 A cm^–2, together with improved C₂₊ selectivities. Computational transport modelling and isotopic C¹⁸O reduction experiments suggest that the enhanced activity is due to a higher surface pH under CO reduction conditions, which facilitates the production of acetate. At optimal operating conditions, we achieve a C₂₊ Faradaic efficiency of ~91% with a C₂₊ partial current density over 630 mA cm^–2. Further investigations show that maintaining an efficient triple-phase boundary at the electrode–electrolyte interface is the most critical challenge in achieving a stable CO/CO₂ electrolysis process at high rates.

以前，据报道一氧化碳电解可产生高达〜55％的增强的多碳（C ₂₊）法拉第效率，但仅在低反应速率下才有效。这是由于CO在水性电解质中的溶解度低以及在间歇式反应器中的运行所致。在这里，我们介绍了一种高性能的CO流电解槽，其电极-电解质界面受到良好控制，可以达到高达1 A cm ^–2的总电流密度，并提高了C _2+的选择性。计算运输模型和同位素C ¹⁸ O还原实验表明，活性增强是由于在CO还原条件下较高的表面pH值，这有助于乙酸盐的产生。在最佳操作条件下，我们获得了C在630 mA cm ^–2上具有C ₂₊分电流密度的₂₊法拉第效率为〜91％。进一步的研究表明，在高速率下实现稳定的CO / CO ₂电解过程中，在电极-电解质界面处保持有效的三相边界是最关键的挑战。