Trade-off between redox potential and strength of electrochemical CO2 capture in quinones

08 July 2022, Version 3
This content is a preprint and has not undergone peer review at the time of posting.


Electrochemical carbon dioxide capture has recently emerged as a promising alternative approach to conventional energy-intensive carbon capture methods. A common electrochemical capture approach is to employ redox-active molecules such as quinones. Upon electrochemical reduction, quinones become activated for the capture of CO2 through a chemical reaction. A key disadvantage of this method is the possibility of side-reactions with oxygen, which is present in almost all gas mixtures of interest for carbon capture. This issue can potentially be mitigated by fine-tuning redox potentials through the introduction of electron-withdrawing groups on the quinone ring. In this article, we investigate the thermodynamics of the electron transfer and chemical steps of CO2 capture in different quinone derivatives with a range of substituents. By combining density functional theory calculations and cyclic voltammetry experiments, we support a previously described trade-off between redox potentials and the strength of CO2 capture. We show that redox potentials can readily be tuned to more positive values to impart stability to oxygen, but as a consequence, significant decreases in CO2 binding free energies are observed. Our calculations support this effect for a large series of anthraquinones and benzoquinones, with different trade-off relationships observed for the two classes of molecules. These trade-offs must be taken into consideration for the design of improved redox-active molecules for electrochemical CO2 capture.


carbon capture
carbon dioxide capture
electrochemical carbon capture
CO2 capture
redox potentials
cyclic voltammetry
density functional theory

Supplementary materials

Supplementary Information
Supplementary Information for “Trade-off between redox potential and strength of electrochemical CO2 capture in quinones”. This includes: Orbital analysis of species in EECC for AQ, Hydrogen bonding in OH case, Substitutions of Me-series, Going from gas phase to solution phase, CV of AQ under O2.


Comments are not moderated before they are posted, but they can be removed by the site moderators if they are found to be in contravention of our Commenting Policy [opens in a new tab] - please read this policy before you post. Comments should be used for scholarly discussion of the content in question. You can find more information about how to use the commenting feature here [opens in a new tab] .
This site is protected by reCAPTCHA and the Google Privacy Policy [opens in a new tab] and Terms of Service [opens in a new tab] apply.