关键词: 电化学还原, 二氧化碳, 流动式MEA反应器, 电解槽

Abstract:

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.

Key words: electrochemical reduction, carbon dioxide, flow MEA reactor, electrolyzer