Challenges in Modeling Electrochemical Reaction Energetics with Polarizable Continuum Models

Joseph A. Gauthier, Stefan Ringe, Colin F. Dickens, Alejandro J. Garza, Alexis T. Bell, Martin Head-Gordon, Jens K. Nørskov, Karen Chan*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

A major challenge in the modeling of electrochemical phenomena is the accurate description of the interface between an electrolyte and a charged conductor. Polarizable continuum models (PCM) have been gaining popularity because they offer a computationally inexpensive method of modeling the electrolyte. In this Perspective, we discuss challenges from using one such model which treats the ions using a linearized Poisson-Boltzmann (LPB) distribution. From a physical perspective, this model places charge unphysically close to the surface and adsorbates, and it includes excessively steep ramping of the dielectric constant from the surface to the bulk solvent. Both of these issues can be somewhat mitigated by adjusting parameters built into the model, but in doing so, the resultant capacitance deviates from experimental values. Likewise, hybrid explicit-implicit approaches to the solvent may offer a more realistic description of hydrogen bonding and solvation to reaction intermediates, but the corresponding capacitances also deviate from experimental values. These deviations highlight the need for a careful adjustment of parameters in order to reproduce not only solvation energies but also other physical properties of solid-liquid interfaces. Continuum approaches alone also necessarily do not capture local variations in the electric field from cations at the interface, which can affect the energetics of intermediates with substantial dipoles or polarizability. Finally, since the double-layer charge can be varied continuously, LPB/PCM models provide a way to determine electrochemical barriers at constant potential. However, double-layer charging and the atomic motion associated with reaction events occur on significantly different timescales. We suggest that more detailed approaches, such as the modified Poisson-Boltzmann model and/or the addition of a Stern layer, may be able to mitigate some but not all of the challenges discussed.
Original languageEnglish
JournalACS Catalysis
Volume9
Issue number2
Pages (from-to)920-931
Number of pages12
ISSN2155-5435
DOIs
Publication statusPublished - 2019

Keywords

  • Density functional theory
  • Catalysis
  • Electrocatalysis
  • Electrochemistry
  • Solvation

Cite this

Gauthier, J. A., Ringe, S., Dickens, C. F., Garza, A. J., Bell, A. T., Head-Gordon, M., ... Chan, K. (2019). Challenges in Modeling Electrochemical Reaction Energetics with Polarizable Continuum Models. ACS Catalysis, 9(2), 920-931. https://doi.org/10.1021/acscatal.8b02793
Gauthier, Joseph A. ; Ringe, Stefan ; Dickens, Colin F. ; Garza, Alejandro J. ; Bell, Alexis T. ; Head-Gordon, Martin ; Nørskov, Jens K. ; Chan, Karen. / Challenges in Modeling Electrochemical Reaction Energetics with Polarizable Continuum Models. In: ACS Catalysis. 2019 ; Vol. 9, No. 2. pp. 920-931.
@article{a852f6ecadba46a1b548bf6b49334bc4,
title = "Challenges in Modeling Electrochemical Reaction Energetics with Polarizable Continuum Models",
abstract = "A major challenge in the modeling of electrochemical phenomena is the accurate description of the interface between an electrolyte and a charged conductor. Polarizable continuum models (PCM) have been gaining popularity because they offer a computationally inexpensive method of modeling the electrolyte. In this Perspective, we discuss challenges from using one such model which treats the ions using a linearized Poisson-Boltzmann (LPB) distribution. From a physical perspective, this model places charge unphysically close to the surface and adsorbates, and it includes excessively steep ramping of the dielectric constant from the surface to the bulk solvent. Both of these issues can be somewhat mitigated by adjusting parameters built into the model, but in doing so, the resultant capacitance deviates from experimental values. Likewise, hybrid explicit-implicit approaches to the solvent may offer a more realistic description of hydrogen bonding and solvation to reaction intermediates, but the corresponding capacitances also deviate from experimental values. These deviations highlight the need for a careful adjustment of parameters in order to reproduce not only solvation energies but also other physical properties of solid-liquid interfaces. Continuum approaches alone also necessarily do not capture local variations in the electric field from cations at the interface, which can affect the energetics of intermediates with substantial dipoles or polarizability. Finally, since the double-layer charge can be varied continuously, LPB/PCM models provide a way to determine electrochemical barriers at constant potential. However, double-layer charging and the atomic motion associated with reaction events occur on significantly different timescales. We suggest that more detailed approaches, such as the modified Poisson-Boltzmann model and/or the addition of a Stern layer, may be able to mitigate some but not all of the challenges discussed.",
keywords = "Density functional theory, Catalysis, Electrocatalysis, Electrochemistry, Solvation",
author = "Gauthier, {Joseph A.} and Stefan Ringe and Dickens, {Colin F.} and Garza, {Alejandro J.} and Bell, {Alexis T.} and Martin Head-Gordon and N{\o}rskov, {Jens K.} and Karen Chan",
year = "2019",
doi = "10.1021/acscatal.8b02793",
language = "English",
volume = "9",
pages = "920--931",
journal = "A C S Catalysis",
issn = "2155-5435",
publisher = "American Chemical Society",
number = "2",

}

Gauthier, JA, Ringe, S, Dickens, CF, Garza, AJ, Bell, AT, Head-Gordon, M, Nørskov, JK & Chan, K 2019, 'Challenges in Modeling Electrochemical Reaction Energetics with Polarizable Continuum Models', ACS Catalysis, vol. 9, no. 2, pp. 920-931. https://doi.org/10.1021/acscatal.8b02793

Challenges in Modeling Electrochemical Reaction Energetics with Polarizable Continuum Models. / Gauthier, Joseph A.; Ringe, Stefan; Dickens, Colin F.; Garza, Alejandro J.; Bell, Alexis T.; Head-Gordon, Martin; Nørskov, Jens K.; Chan, Karen.

In: ACS Catalysis, Vol. 9, No. 2, 2019, p. 920-931.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Challenges in Modeling Electrochemical Reaction Energetics with Polarizable Continuum Models

AU - Gauthier, Joseph A.

AU - Ringe, Stefan

AU - Dickens, Colin F.

AU - Garza, Alejandro J.

AU - Bell, Alexis T.

AU - Head-Gordon, Martin

AU - Nørskov, Jens K.

AU - Chan, Karen

PY - 2019

Y1 - 2019

N2 - A major challenge in the modeling of electrochemical phenomena is the accurate description of the interface between an electrolyte and a charged conductor. Polarizable continuum models (PCM) have been gaining popularity because they offer a computationally inexpensive method of modeling the electrolyte. In this Perspective, we discuss challenges from using one such model which treats the ions using a linearized Poisson-Boltzmann (LPB) distribution. From a physical perspective, this model places charge unphysically close to the surface and adsorbates, and it includes excessively steep ramping of the dielectric constant from the surface to the bulk solvent. Both of these issues can be somewhat mitigated by adjusting parameters built into the model, but in doing so, the resultant capacitance deviates from experimental values. Likewise, hybrid explicit-implicit approaches to the solvent may offer a more realistic description of hydrogen bonding and solvation to reaction intermediates, but the corresponding capacitances also deviate from experimental values. These deviations highlight the need for a careful adjustment of parameters in order to reproduce not only solvation energies but also other physical properties of solid-liquid interfaces. Continuum approaches alone also necessarily do not capture local variations in the electric field from cations at the interface, which can affect the energetics of intermediates with substantial dipoles or polarizability. Finally, since the double-layer charge can be varied continuously, LPB/PCM models provide a way to determine electrochemical barriers at constant potential. However, double-layer charging and the atomic motion associated with reaction events occur on significantly different timescales. We suggest that more detailed approaches, such as the modified Poisson-Boltzmann model and/or the addition of a Stern layer, may be able to mitigate some but not all of the challenges discussed.

AB - A major challenge in the modeling of electrochemical phenomena is the accurate description of the interface between an electrolyte and a charged conductor. Polarizable continuum models (PCM) have been gaining popularity because they offer a computationally inexpensive method of modeling the electrolyte. In this Perspective, we discuss challenges from using one such model which treats the ions using a linearized Poisson-Boltzmann (LPB) distribution. From a physical perspective, this model places charge unphysically close to the surface and adsorbates, and it includes excessively steep ramping of the dielectric constant from the surface to the bulk solvent. Both of these issues can be somewhat mitigated by adjusting parameters built into the model, but in doing so, the resultant capacitance deviates from experimental values. Likewise, hybrid explicit-implicit approaches to the solvent may offer a more realistic description of hydrogen bonding and solvation to reaction intermediates, but the corresponding capacitances also deviate from experimental values. These deviations highlight the need for a careful adjustment of parameters in order to reproduce not only solvation energies but also other physical properties of solid-liquid interfaces. Continuum approaches alone also necessarily do not capture local variations in the electric field from cations at the interface, which can affect the energetics of intermediates with substantial dipoles or polarizability. Finally, since the double-layer charge can be varied continuously, LPB/PCM models provide a way to determine electrochemical barriers at constant potential. However, double-layer charging and the atomic motion associated with reaction events occur on significantly different timescales. We suggest that more detailed approaches, such as the modified Poisson-Boltzmann model and/or the addition of a Stern layer, may be able to mitigate some but not all of the challenges discussed.

KW - Density functional theory

KW - Catalysis

KW - Electrocatalysis

KW - Electrochemistry

KW - Solvation

U2 - 10.1021/acscatal.8b02793

DO - 10.1021/acscatal.8b02793

M3 - Journal article

VL - 9

SP - 920

EP - 931

JO - A C S Catalysis

JF - A C S Catalysis

SN - 2155-5435

IS - 2

ER -

Gauthier JA, Ringe S, Dickens CF, Garza AJ, Bell AT, Head-Gordon M et al. Challenges in Modeling Electrochemical Reaction Energetics with Polarizable Continuum Models. ACS Catalysis. 2019;9(2):920-931. https://doi.org/10.1021/acscatal.8b02793