Electrochemical CO2 capture with pH-independent redox chemistry

Fuente: arXiv
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Main Authors: Kim, Sang Cheol, Gigantino, Marco, Holoubek, John, Matthews, Jesse E., Chen, Junjie, Dho, Yaereen, Jaramillo, Thomas F., Cui, Yi, Majumdar, Arun, Tzeng, Yan-Kai, Chu, Steven
Format: Preprint
Published: 2025
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author Kim, Sang Cheol
Gigantino, Marco
Holoubek, John
Matthews, Jesse E.
Chen, Junjie
Dho, Yaereen
Jaramillo, Thomas F.
Cui, Yi
Majumdar, Arun
Tzeng, Yan-Kai
Chu, Steven
author_facet Kim, Sang Cheol
Gigantino, Marco
Holoubek, John
Matthews, Jesse E.
Chen, Junjie
Dho, Yaereen
Jaramillo, Thomas F.
Cui, Yi
Majumdar, Arun
Tzeng, Yan-Kai
Chu, Steven
contents Capture of anthropogenic CO2 is critical for mitigating climate change, and reducing the energy cost is essential for wide-scale deployment. Solubility of inorganic carbon in aqueous solutions depends on the pH, and electrochemical modulation of the pH has been investigated as a means of CO2 capture and release. However, reported methods incur unavoidable energy costs due to thermodynamic penalties. In this study, we introduce a pH-independent redox chemistry that greatly lowers the thermodynamic energy costs by changing the pH without directly changing the [H+]. We show that the redox reaction of TEMPO molecules modulates the pH for capture and release of CO2 in a flow cell with an energy cost as low as 2.6 kJ/mol of CO2 corresponding to 0.027 eV/molecule. A molecular model, supported by MD and DFT simulations, is proposed of how the pH is decreased by 7.6 while largely avoiding the entropic energy cost associated with increasing the [H+]. We believe that this work showcases the potential of pH-independent redox chemistries for practical and cost-effective CO2 capture.
format Preprint
id arxiv_https___arxiv_org_abs_2502_01028
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Electrochemical CO2 capture with pH-independent redox chemistry
Kim, Sang Cheol
Gigantino, Marco
Holoubek, John
Matthews, Jesse E.
Chen, Junjie
Dho, Yaereen
Jaramillo, Thomas F.
Cui, Yi
Majumdar, Arun
Tzeng, Yan-Kai
Chu, Steven
Chemical Physics
Capture of anthropogenic CO2 is critical for mitigating climate change, and reducing the energy cost is essential for wide-scale deployment. Solubility of inorganic carbon in aqueous solutions depends on the pH, and electrochemical modulation of the pH has been investigated as a means of CO2 capture and release. However, reported methods incur unavoidable energy costs due to thermodynamic penalties. In this study, we introduce a pH-independent redox chemistry that greatly lowers the thermodynamic energy costs by changing the pH without directly changing the [H+]. We show that the redox reaction of TEMPO molecules modulates the pH for capture and release of CO2 in a flow cell with an energy cost as low as 2.6 kJ/mol of CO2 corresponding to 0.027 eV/molecule. A molecular model, supported by MD and DFT simulations, is proposed of how the pH is decreased by 7.6 while largely avoiding the entropic energy cost associated with increasing the [H+]. We believe that this work showcases the potential of pH-independent redox chemistries for practical and cost-effective CO2 capture.
title Electrochemical CO2 capture with pH-independent redox chemistry
topic Chemical Physics
url https://arxiv.org/abs/2502.01028