Zhu Hao-Lin, Huang Jia-Run, Zhang Meng-Di, Yu Can, Liao Pei-Qin, Chen Xiao-Ming
MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, GBRCE for Functional Molecular Engineering, School of Chemistry, IGCME, Sun Yat-Sen University, Guangzhou 510275, China.
Institute of High Energy Physics, Chinese Academy of Sciences (CAS), Beijing 100049, China.
J Am Chem Soc. 2024 Jan 10;146(1):1144-1152. doi: 10.1021/jacs.3c12423. Epub 2024 Jan 2.
It is crucial to achieve continuous production of highly concentrated and pure C chemicals through the electrochemical CO reduction reaction (eCORR) for artificial carbon cycling, yet it has remained unattainable until now. Despite one-pot tandem catalysis (dividing the eCORR to C into two catalytical reactions of CO to CO and CO to C) offering the potential for significantly enhancing reaction efficiency, its mechanism remains unclear and its performance is unsatisfactory. Herein, we selected different CO-to-CO catalysts and CO-to-acetate catalysts to construct several tandem catalytic systems for the eCORR to acetic acid. Among them, a tandem catalytic system comprising a covalent organic framework () and a metal-organic framework () as CO-to-CO and CO-to-acetate catalysts, respectively, exhibited a faradaic efficiency of 51.2% with a current density of 410 mA cm and an ultrahigh acetate yield rate of 2.72 mmol m s under neutral conditions. After electrolysis for 200 h, 1 cm working electrode can continuously produce 20 mM acetic acid aqueous solution with a relative purity of 95+%. Comprehensive studies revealed that the performance of tandem catalysts is influenced not only by the CO supply-demand relationship and electron competition between the two catalytic processes in the one-pot tandem system but also by the performance of the CO-to-C catalyst under diluted CO conditions.
通过电化学CO还原反应（eCORR）实现高浓度、高纯度C化学品的连续生产对于人工碳循环至关重要，但迄今为止仍无法实现。尽管一锅串联催化（将eCORR制C分为CO到CO和CO到C的两个催化反应）具有显著提高反应效率的潜力，但其机理仍不清楚，性能也不尽人意。在此，我们选择了不同的CO到CO催化剂和CO到乙酸盐催化剂来构建几个用于eCORR制乙酸的串联催化体系。其中，一个分别以共价有机框架（）和金属有机框架（）作为CO到CO和CO到乙酸盐催化剂的串联催化体系，在中性条件下，法拉第效率为51.2%，电流密度为410 mA cm，乙酸盐产率高达2.72 mmol m s。电解200小时后，1 cm工作电极可连续生产相对纯度为95%以上的20 mM乙酸水溶液。综合研究表明，串联催化剂的性能不仅受一锅串联体系中两个催化过程之间的CO供需关系和电子竞争的影响，还受稀释CO条件下CO到C催化剂性能的影响。
