中山大学廖培钦团队报道了通过直接电还原CO₂连续生产高浓度纯乙酸水溶液。相关研究成果发表在2024年1月2日出版的国际学术期刊《美国化学会杂志》。

通过用于人工碳循环的电化学CO₂还原反应（eCO₂RR）实现高浓度和纯C2化学品的连续生产至关重要，但迄今为止仍未实现。尽管一锅串联催化（将eCO₂RR到C₂分为CO₂到CO和CO到C2的两个催化反应）提供了显著提高反应效率的潜力，但其机理仍不清楚，其性能也不令人满意。

该文中，研究人员选择了不同的CO₂到CO催化剂和CO到乙酸盐催化剂来构建几种用于eCO₂RR到乙酸的串联催化体系。其中，包括共价有机框架（PcNi DMTP）和金属-有机框架（MAF-2）分别作为CO₂到CO和CO到乙酸盐催化剂的串联催化体系，在中性条件下，电流密度为410 mA cm^–2，法拉第效率为51.2%，超高乙酸盐产率为2.72 mmol m^–2 s^–1。电解200小时后，1 cm^–2的工作电极可以连续产生20 mM的乙酸水溶液，相对纯度为95+%。

综合研究表明，串联催化剂的性能不仅受一锅串联系统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-C₂催化剂的性能的影响。

附：英文原文

Title: Continuously Producing Highly Concentrated and Pure Acetic Acid Aqueous Solution via Direct Electroreduction of CO2

Author: Hao-Lin Zhu, Jia-Run Huang, Meng-Di Zhang, Can Yu, Pei-Qin Liao, Xiao-Ming Chen

Issue&Volume: January 2, 2024

Abstract: It is crucial to achieve continuous production of highly concentrated and pure C2 chemicals through the electrochemical CO2 reduction reaction (eCO2RR) for artificial carbon cycling, yet it has remained unattainable until now. Despite one-pot tandem catalysis (dividing the eCO2RR to C2 into two catalytical reactions of CO2 to CO and CO to C2) offering the potential for significantly enhancing reaction efficiency, its mechanism remains unclear and its performance is unsatisfactory. Herein, we selected different CO2-to-CO catalysts and CO-to-acetate catalysts to construct several tandem catalytic systems for the eCO2RR to acetic acid. Among them, a tandem catalytic system comprising a covalent organic framework (PcNi-DMTP) and a metal–organic framework (MAF-2) as CO2-to-CO and CO-to-acetate catalysts, respectively, exhibited a faradaic efficiency of 51.2% with a current density of 410 mA cm–2 and an ultrahigh acetate yield rate of 2.72 mmol m–2 s–1 under neutral conditions. After electrolysis for 200 h, 1 cm–2 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-C2 catalyst under diluted CO conditions.

DOI: 10.1021/jacs.3c12423

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.3c12423