Yang Yingliang, Gao Hongshuai, Feng Jiaqi, Zeng Shaojuan, Liu Lei, Liu Licheng, Ren Baozeng, Li Tao, Zhang Suojiang, Zhang Xiangping
Beijing Key Laboratory of Ionic Liquids Clean Process, State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, P. R. China.
College of Chemical Engineering, Zhengzhou University, Zhengzhou, 450001, P. R. China.
ChemSusChem. 2020 Sep 18;13(18):4900-4905. doi: 10.1002/cssc.202001194. Epub 2020 Aug 13.
Electrochemical reduction of CO into valuable chemicals is a significant route to utilize CO resources. Among various electroreduction products, oxalic acid (H C O ) is an important chemical for pharmaceuticals, rare earth extraction, and metal processing. Here, an aprotic aromatic ester-functionalized ionic liquid (IL), 4-(methoxycarbonyl) phenol tetraethylammonium ([TEA][4-MF-PhO]), was designed as an electrolyte for CO electroreduction into oxalic acid. It exhibited a large oxalic acid partial current density of 9.03 mA cm with a faradaic efficiency (FE) of 86 % at -2.6 V (vs. Ag/Ag ), and the oxalic acid formation rate was as high as 168.4 μmol cm h , which is the highest reported value to date. Moreover, the results of density functional theory calculations demonstrated that CO was efficiently activated to a -COOH intermediate by bis-active sites of the aromatic ester anion via the formation of a [4-MF-PhO-COOH] adduct, which finally dimerized into oxalic acid.
将CO电化学还原为有价值的化学品是利用CO资源的重要途径。在各种电还原产物中，草酸（H₂C₂O₄）是用于制药、稀土萃取和金属加工的重要化学品。在此，设计了一种非质子芳香酯功能化离子液体（IL），4-（甲氧基羰基）苯酚四乙铵（[TEA][4-MF-PhO]）作为将CO电还原为草酸的电解质。在-2.6 V（相对于Ag/Ag⁺）时，它表现出9.03 mA cm⁻²的大草酸分电流密度，法拉第效率（FE）为86%，草酸形成速率高达168.4 μmol cm⁻² h⁻¹，这是迄今为止报道的最高值。此外，密度泛函理论计算结果表明，通过形成[4-MF-PhO-COOH]加合物，CO被芳香酯阴离子的双活性位点有效地活化成-COOH中间体，最终二聚成草酸。
