Super-Nernstian Shifts of Interfacial Proton-Coupled Electron Transfers

Origin and Effect of Noncovalent Interactions

Christopher Wildi, Gema Cabello, Martin E Zoloff Michoff, Patricio Velez, Ezequiel P. M. Leiva, Juan Jose Calvente, Rafael Andreu, Angel Cuesta

Research output: Contribution to journalArticle

8 Citations (Scopus)
6 Downloads (Pure)

Abstract

Anions whose specific adsorption involves a proton-coupled electron transfer (PCET) include adsorbed OH (OHad), which plays an enormously relevant role in many fuel-cell reactions. OHad formation has often been found to happen in alkaline solutions at potentials more negative than expected from a Nerstian shift, and this has been proposed as the reason for the often easier oxidation of organic molecules in alkaline media, as compared to acids. Non-covalent interactions with electrolyte cations have also been shown to affect the stability of OHad. Using cyanide-modified Pt(111) as a model, we show here that interfacial PCETs will show a super-Nernstian shift if (i) less than one electron per proton is transferred, and (ii) the plane of proton-electron transfer and that of the metal surface do not coincide. We also show that electrolyte cations have a double effect: they provoke an additional shift by blocking the site of transfer, but decrease the super-Nernstian contribution by separating the plane of transfer from the outer Helmholtz plane (OHP).
Original languageEnglish
Pages (from-to)15586-15592
Number of pages7
JournalThe Journal of Physical Chemistry C
Volume120
Issue number29
Early online date6 Jul 2015
DOIs
Publication statusPublished - 28 Jul 2016

Fingerprint

Protons
electron transfer
Electrolytes
protons
Cations
Electrons
shift
Positive ions
electrolytes
cations
Cyanides
interactions
cyanides
fuel cells
metal surfaces
Anions
Fuel cells
Negative ions
Metals
anions

Cite this

Super-Nernstian Shifts of Interfacial Proton-Coupled Electron Transfers : Origin and Effect of Noncovalent Interactions. / Wildi, Christopher; Cabello, Gema; Zoloff Michoff, Martin E; Velez, Patricio; Leiva, Ezequiel P. M.; Calvente, Juan Jose; Andreu, Rafael; Cuesta, Angel.

In: The Journal of Physical Chemistry C, Vol. 120, No. 29, 28.07.2016, p. 15586-15592.

Research output: Contribution to journalArticle

Wildi, Christopher ; Cabello, Gema ; Zoloff Michoff, Martin E ; Velez, Patricio ; Leiva, Ezequiel P. M. ; Calvente, Juan Jose ; Andreu, Rafael ; Cuesta, Angel. / Super-Nernstian Shifts of Interfacial Proton-Coupled Electron Transfers : Origin and Effect of Noncovalent Interactions. In: The Journal of Physical Chemistry C. 2016 ; Vol. 120, No. 29. pp. 15586-15592.
@article{c4c22639f36a4ed2b48aa7e560f79894,
title = "Super-Nernstian Shifts of Interfacial Proton-Coupled Electron Transfers: Origin and Effect of Noncovalent Interactions",
abstract = "Anions whose specific adsorption involves a proton-coupled electron transfer (PCET) include adsorbed OH (OHad), which plays an enormously relevant role in many fuel-cell reactions. OHad formation has often been found to happen in alkaline solutions at potentials more negative than expected from a Nerstian shift, and this has been proposed as the reason for the often easier oxidation of organic molecules in alkaline media, as compared to acids. Non-covalent interactions with electrolyte cations have also been shown to affect the stability of OHad. Using cyanide-modified Pt(111) as a model, we show here that interfacial PCETs will show a super-Nernstian shift if (i) less than one electron per proton is transferred, and (ii) the plane of proton-electron transfer and that of the metal surface do not coincide. We also show that electrolyte cations have a double effect: they provoke an additional shift by blocking the site of transfer, but decrease the super-Nernstian contribution by separating the plane of transfer from the outer Helmholtz plane (OHP).",
author = "Christopher Wildi and Gema Cabello and {Zoloff Michoff}, {Martin E} and Patricio Velez and Leiva, {Ezequiel P. M.} and Calvente, {Juan Jose} and Rafael Andreu and Angel Cuesta",
note = "The support of the University of Aberdeen is gratefully acknowledged. C.W. acknowledges a summer studentship from the Carnegie Trust for the Universities of Scotland. E.P.M.L. acknowledges SeCYT (Universidad Nacional de Cordoba), ́ CONICET- PIP 11220110100992, Program BID (PICT 2012-2324), and PME 2006-01581 for financial support.",
year = "2016",
month = "7",
day = "28",
doi = "10.1021/acs.jpcc.5b04560",
language = "English",
volume = "120",
pages = "15586--15592",
journal = "The Journal of Physical Chemistry C",
issn = "1932-7447",
publisher = "American Chemical Society",
number = "29",

}

TY - JOUR

T1 - Super-Nernstian Shifts of Interfacial Proton-Coupled Electron Transfers

T2 - Origin and Effect of Noncovalent Interactions

AU - Wildi, Christopher

AU - Cabello, Gema

AU - Zoloff Michoff, Martin E

AU - Velez, Patricio

AU - Leiva, Ezequiel P. M.

AU - Calvente, Juan Jose

AU - Andreu, Rafael

AU - Cuesta, Angel

N1 - The support of the University of Aberdeen is gratefully acknowledged. C.W. acknowledges a summer studentship from the Carnegie Trust for the Universities of Scotland. E.P.M.L. acknowledges SeCYT (Universidad Nacional de Cordoba), ́ CONICET- PIP 11220110100992, Program BID (PICT 2012-2324), and PME 2006-01581 for financial support.

PY - 2016/7/28

Y1 - 2016/7/28

N2 - Anions whose specific adsorption involves a proton-coupled electron transfer (PCET) include adsorbed OH (OHad), which plays an enormously relevant role in many fuel-cell reactions. OHad formation has often been found to happen in alkaline solutions at potentials more negative than expected from a Nerstian shift, and this has been proposed as the reason for the often easier oxidation of organic molecules in alkaline media, as compared to acids. Non-covalent interactions with electrolyte cations have also been shown to affect the stability of OHad. Using cyanide-modified Pt(111) as a model, we show here that interfacial PCETs will show a super-Nernstian shift if (i) less than one electron per proton is transferred, and (ii) the plane of proton-electron transfer and that of the metal surface do not coincide. We also show that electrolyte cations have a double effect: they provoke an additional shift by blocking the site of transfer, but decrease the super-Nernstian contribution by separating the plane of transfer from the outer Helmholtz plane (OHP).

AB - Anions whose specific adsorption involves a proton-coupled electron transfer (PCET) include adsorbed OH (OHad), which plays an enormously relevant role in many fuel-cell reactions. OHad formation has often been found to happen in alkaline solutions at potentials more negative than expected from a Nerstian shift, and this has been proposed as the reason for the often easier oxidation of organic molecules in alkaline media, as compared to acids. Non-covalent interactions with electrolyte cations have also been shown to affect the stability of OHad. Using cyanide-modified Pt(111) as a model, we show here that interfacial PCETs will show a super-Nernstian shift if (i) less than one electron per proton is transferred, and (ii) the plane of proton-electron transfer and that of the metal surface do not coincide. We also show that electrolyte cations have a double effect: they provoke an additional shift by blocking the site of transfer, but decrease the super-Nernstian contribution by separating the plane of transfer from the outer Helmholtz plane (OHP).

U2 - 10.1021/acs.jpcc.5b04560

DO - 10.1021/acs.jpcc.5b04560

M3 - Article

VL - 120

SP - 15586

EP - 15592

JO - The Journal of Physical Chemistry C

JF - The Journal of Physical Chemistry C

SN - 1932-7447

IS - 29

ER -