Acidic CO 2 electroreduction into carbon products via surface modification of CuNPs catalysts functionalized with different crown ethers Hai Nam Ha, Ngoc Huan Tran, Marc Fontecave Laboratoire de Chimie des Processus Biologiques, Collège de France, 11 pl. Marcelin Berthelot, Paris, France email: hai-nam.ha@college-de-france.fr Conducting CO2 electroreduction in alkaline electrolyte has several advantages including easily achieves high faradic efficiency as well as high current density. But in this process, CO2 can react rapidly with OH- to form carbonates (CO32-) or bicarbonate (HCO3-) which leads to CO2 loss. Therefore, to avoid CO2 loss during CO2 electrolysis process, acidic electrolyte is a feasible solution to solve this problem because formed carbonate will react with excess proton to reproduce CO2. However, the drawback of running CO2 electroreduction in acidic condition is that it facilitates HER. So, this project is designed to lowering alkali cation in acidic CO2 electroreduction into carbon products using Cu-based catalysts via surface modification via crown ether-alkali cation complex immobilization. We anticipate that the presence of positively charged alkali cation on the electrode surface would inhibit hydrogen evolution and promote high selectivity of methane production. A series of different crown-ethers have been selected to investigate their effects on CO2 reduction. With the study was carried out using flow electrolyzer, it allows to test the catalytic activity at the current density larger than 100 mA.cm-2. The highest selectivity of methane production is obtained at 150 mA/cm-2, with the FE could reach to higher than 55%, which is remarkable value from CO2 reduction in acidic media. References 1. Xu, Keqiang, et al. "Favoring CO intermediate stabilization and protonation by crown ether for CO2 electromethanation in acidic media." Angewandte Chemie 135.50 (2023): e202311968. 2. Perazio, Alessandro, et al. "Acidic electroreduction of CO2 to multi-carbon products with CO2 recovery and recycling from carbonate." ACS Energy Letters 8.7 (2023): 2979-2985. 3. Vichou, Elli, et al. "Tuning selectivity of acidic carbon dioxide electrolysis via surface modification." Chemistry of Materials 35.17 (2023): 7060-7068. 4. Shen, Shuchao, et al. "Advancements and challenges of industrial-level acidic CO2 electrolysis." MetalMat 1.2 (2024): e28.
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