电化学二氧化碳还原反应（CO₂RR）是一种利用间歇性可再生电力缓解环境问题,并且生产液体燃料和工业化学品的有前途的方法。然而,传统的H型反应器由于在电解液中较低的CO₂溶解度以及两电极之间较大的极距而导致高欧姆电阻,严重限制了CO₂RR的电化学性能,不利于CO₂RR在工业应用的发展。在本文中,我们设计了一种基于0.5 mol·L^-1 KHCO₃的自生长Cu/Sn双金属电催化剂的高性能连续流膜电极组件（MEA）反应器,用于将CO₂转化为甲酸。与H型反应器相比,流动式MEA反应器不仅显示出优异的电流密度（-1.11 V_RHE时电流密度为66.41 mA·cm^-2）,而且还保持了较高的甲酸法拉第效率（89.56%）,并且能够稳定工作至少20 h。本文还设计了一套新型CO₂RR系统,可以有效地分离气态/液态产物。出乎意料的是,在-0.91 V_RHE且电池电压为3.17 V时,甲酸的生产率为163 μmol·h^-1·cm^-2。本文为克服电化学CO₂RR的传质限制以及分离液体和气体产物提供了一条新途径。

The electrochemical carbon dioxide reduction reaction (CO₂RR) is a promising approach to produce liquid fuels and industrial chemicals by utilizing intermittent renewable electricity for mitigating environmental problems. However, the traditional H-type reactor seriously limits the electrochemical performance of CO₂RR due to the low CO₂ solubility in electrolyte, and high ohmic resistance caused by the large distance between two electrodes, which is unbeneficial for industrial application. Herein, we demonstrated a high-performance continuous flow membranes electrode assembly (MEA) reactor based on a self-growing Cu/Sn bimetallic electrocatalyst in 0.5 mol·L^-1 KHCO₃ for converting CO₂ to formate. Compared with an H-type cell, the MEA reactor not only shows the excellent current density (66.41 mA·cm^-2 at -1.11 V_RHE), but also maintains high Faraday efficiency of formate (89.56%) with the steady work around 20 h. Notably, we also designed the new CO₂RR system to effectively separate the gaseous/liquid production. Surprisingly, the production rate of formate reached 163 μmol·h^-1·cm^-2 at -0.91 V_RHE with the cell voltage of 3.17 V. This study provides a promising path to overcome mass transport limitations of the electrochemical CO₂RR and to separate liquid from gas products.