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Aromatic Ester‐Functionalized Ionic Liquid for Highly Efficient CO 2 Electrochemical Reduction to Oxalic Acid
Author(s) -
Yang Yingliang,
Gao Hongshuai,
Feng Jiaqi,
Zeng Shaojuan,
Liu Lei,
Liu Licheng,
Ren Baozeng,
Li Tao,
Zhang Suojiang,
Zhang Xiangping
Publication year - 2020
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.202001194
Subject(s) - oxalic acid , chemistry , ionic liquid , electrochemistry , inorganic chemistry , organic chemistry , catalysis , electrode
Electrochemical reduction of CO 2 into valuable chemicals is a significant route to utilize CO 2 resources. Among various electroreduction products, oxalic acid (H 2 C 2 O 4 ) 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 2 electroreduction into oxalic acid. It exhibited a large oxalic acid partial current density of 9.03 mA cm −2 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 −2 h −1 , which is the highest reported value to date. Moreover, the results of density functional theory calculations demonstrated that CO 2 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.