Xing Kewen, Wang Mengjing, Pan Binbin, Liang Chenglin, Li Yanguang
Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou, 215123, China.
Jiangsu Key Laboratory for Advanced Negative Carbon Technologies, Soochow University, Suzhou, 215123, China.
Angew Chem Int Ed Engl. 2025 Jul 28;64(31):e202504835. doi: 10.1002/anie.202504835. Epub 2025 May 19.
Electrochemical CO reduction (CORR) is a promising method for converting CO into valuable chemicals, with formate being a particularly viable product. However, current gas-fed CORR systems rely on highly pure CO feed gases and are incompatible with point-source CO emissions without prior capture and concentration. Bicarbonate electrolysis offers a potential solution by bridging the gap between CO emissions and utilization. However, existing electrolyzer configurations, especially those using bipolar membranes (BPM), require high working voltages and suffer from poor energy efficiency. Here, we present a cation exchange membrane (CEM)-based membrane electrode assembly (MEA) incorporating a surface-modified bismuth cathode catalyst. The success of this approach is attributed to two key factors: the use of the positively charged ionomer PiperION for surface modification, which creates a favorable cathode microenvironment; the single CEM that enhances proton flux from the anode to the cathode while reducing ionic impedance. The CEM-based MEA demonstrates a formate faradaic efficiency of up to 80%, with a significant 1.5 V reduction in operating voltage compared to BPM-based MEAs at 300 mA cm. Additionally, the CEM-based MEA exhibits excellent tolerance to O impurities and maintains high performance even with simulated flue gas, making it suitable for direct CO utilization from point sources.
电化学一氧化碳还原（CORR）是一种将一氧化碳转化为有价值化学品的有前景的方法，甲酸盐是一种特别可行的产物。然而，目前的气体进料CORR系统依赖于高纯度的一氧化碳进料气体，并且在没有预先捕获和浓缩的情况下与点源一氧化碳排放不兼容。碳酸氢盐电解通过弥合一氧化碳排放与利用之间的差距提供了一种潜在的解决方案。然而，现有的电解槽配置，特别是那些使用双极膜（BPM）的配置，需要高工作电压并且能源效率低下。在这里，我们展示了一种基于阳离子交换膜（CEM）的膜电极组件（MEA），其包含表面改性的铋阴极催化剂。这种方法的成功归因于两个关键因素：使用带正电荷的离聚物PiperION进行表面改性，这创造了有利的阴极微环境；单一的CEM增强了质子从阳极到阴极的通量，同时降低了离子阻抗。基于CEM的MEA显示出高达80%的甲酸盐法拉第效率，在300 mA/cm²时，与基于BPM的MEA相比，工作电压显著降低了1.5 V。此外，基于CEM的MEA对氧气杂质表现出优异的耐受性，即使使用模拟烟道气也能保持高性能，使其适用于从点源直接利用一氧化碳。
