Modeling voltammetry curves for proton coupled electron transfer: The importance of nuclear quantum effects
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.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jun 16, 2020
- Source ID
- 10.1063/5.0010412
Entities
People
- Alec J Coffman
- Joseph E Subotnik
- Sharon Hammes-Schiffer
- Wenjie Dou
Organizations
- United States Air Force
- University of Pennsylvania
- Yale University
- Yusuf Hamied Department of Chemistry