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Electrochemical upgrade of CO2 from amine capture solution


CO2 capture technologies based on chemisorption present the potential to lower net emissions of CO2 into the atmosphere. The electrochemical upgrade of captured CO2 to value-added products would be particularly convenient. Here we find that this goal is curtailed when the adduct of the capture molecule with CO2 fails to place the CO2 sufficiently close to the site of the heterogeneous reaction. We investigate tailoring the electrochemical double layer to achieve the valorization of chemisorbed CO2 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 CO2 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–CO2 conversion to CO with 72% Faradaic efficiency at 50 mA cm–2.

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Fig. 1: The EDL in the case of MEA electrolyte.
Fig. 2: Proposed interfacial structure near the electrode surface.
Fig. 3: The EDL in the case of the MEA/KCl electrolyte.
Fig. 4: The EDL tailored using different cations.
Fig. 5: Electrochemical performances of captured CO2 electrolysis.

Data availability

The authors declare that all data supporting the findings of this study are available within the paper and Supplementary Information files. Source data are provided with this paper.


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We acknowledge the support of the Ontario Research Fund and the Natural Sciences and Engineering Research Council (NSERC) of Canada. This research was supported by the Creative Materials Discovery Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT and Future Planning (2017M3D1A1040689).

Author information




G.L. and Y.C.L. contributed to all experimental works, data analysis and manuscript preparation. J.-Y.K. and Y.-C.J. contributed to electrochemical experiments and NMR analysis. T.P. conducted the gas chromatography mass spectrometry analysis with the labelled 13CO2. D.-H.N. and A.S.R. conducted catalyst characterization. F.L. and M.L. contributed to discussions of the mechanism. A.H.I. participated in discussion of the energy analysis. E.H.S. supervised this study.

Corresponding author

Correspondence to Edward H. Sargent.

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The authors declare no competing interests.

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Peer review information Nature Energy thanks Sichao Ma and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Supplementary information

Supplementary Information

Supplementary Notes 1–2, Figs. 1–20 and Tables 1–8.

Supplementary Data 1

Supplementary data for Supplementary Tables 1–5 and Supplementary Figs. 1, 3–7, 9–11 and 13–20.

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Source Data Fig. 1

Numerical data for Fig. 1.

Source Data Fig. 3

Numerical data for Fig. 3.

Source Data Fig. 4

Numerical data for Fig. 4.

Source Data Fig. 5

Numerical data for Fig. 5.

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Lee, G., Li, Y.C., Kim, JY. et al. Electrochemical upgrade of CO2 from amine capture solution. Nat Energy 6, 46–53 (2021).

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