Electrochemical upgrade of CO2 from amine capture solution

• Published in: Nature energy Vol. 6; no. 1; pp. 46 - 53
• Main Authors: Lee, Geonhui, Li, Yuguang C., Kim, Ji-Yong, Peng, Tao, Nam, Dae-Hyun, Sedighian Rasouli, Armin, Li, Fengwang, Luo, Mingchuan, Ip, Alexander H., Joo, Young-Chang, Sargent, Edward H.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.01.2021; Nature Publishing Group
• Subjects: 639/301/299/886; 639/4077/4057; 639/4077/909/4101/4102; 639/638/161; Carbon dioxide; Carbon sequestration; Chemisorption; Conversion; Economics and Management; Electric double layer; Electrochemistry; Electrolytes; Emissions; Energy; Energy Policy; Energy Storage; Energy Systems; Mass transport; Monoethanolamine (MEA); Raman spectroscopy; Renewable and Green Energy; Systems design
• ISSN: 2058-7546; 2058-7546
• DOI: 10.1038/s41560-020-00735-z

CO 2 capture technologies based on chemisorption present the potential to lower net emissions of CO 2 into the atmosphere. The electrochemical upgrade of captured CO 2 to value-added products would be particularly convenient. Here we find that this goal is curtailed when the adduct of the capture molecule with CO 2 fails to place the CO 2 sufficiently close to the site of the heterogeneous reaction. We investigate tailoring the electrochemical double layer to achieve the valorization of chemisorbed CO 2 in an aqueous monoethanolamine electrolyte. We reveal, using electrochemical studies and in situ surface-enhanced Raman spectroscopy, that a smaller double layer distance correlates with improved activity for CO 2 to CO from amine solutions. With the aid of an alkali cation and accelerated mass transport by system design—temperature and concentration—we demonstrate amine–CO 2 conversion to CO with 72% Faradaic efficiency at 50 mA cm –2 . Electrochemical conversion of CO 2 into high-value products is attractive for lowering net carbon emissions. Lee et al. present the valorization of chemisorbed CO 2 to CO in an aqueous monoethanolamine electrolyte via tailoring of the electrochemical double layer, with 72% Faradaic efficiency at 50 mA cm –2 .