Modeling voltammetry curves for proton coupled electron transfer: The importance of nuclear quantum effects

Alec J. Coffman, Wenjie Dou, Sharon Hammes-Schiffer, Joseph E. Subotnik

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

We investigate rates of proton-coupled electron transfer (PCET) in potential sweep experiments for a generalized Anderson-Holstein model with the inclusion of a quantized proton coordinate. To model this system, we utilize a quantum classical Liouville equation embedded inside of a classical master equation, which can be solved approximately with a recently developed algorithm combining diffusional effects and surface hopping between electronic states. We find that the addition of nuclear quantum effects through the proton coordinate can yield quantitatively (but not qualitatively) different IV curves under a potential sweep compared to electron transfer (ET). Additionally, we find that kinetic isotope effects give rise to a shift in the peak potential, but not the peak current, which would allow for quantification of whether an electrochemical ET event is proton-coupled or not. These findings suggest that it will be very difficult to completely understand coupled nuclear-electronic effects in electrochemical voltammetry experiments using only IV curves, and new experimental techniques will be needed to draw inferences about the nature of electrochemical PCET.

Original languageEnglish (US)
Article number234108
JournalJournal of Chemical Physics
Volume152
Issue number23
DOIs
StatePublished - Jun 21 2020
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General Physics and Astronomy
  • Physical and Theoretical Chemistry

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