kang-adiabaticversus-2021.pdf (7.7 MB)
Adiabatic versus non-adiabatic electron transfer at 2D electrode materials
journal contribution
posted on 2021-01-01, 00:00 authored by D Q Liu, Minkyung KangMinkyung Kang, D Perry, C H Chen, G West, X Xia, S Chaudhuri, Z P L Laker, N R Wilson, G N Meloni, M M Melander, R J Maurer, P R UnwinAbstract2D electrode materials are often deployed on conductive supports for electrochemistry and there is a great need to understand fundamental electrochemical processes in this electrode configuration. Here, an integrated experimental-theoretical approach is used to resolve the key electronic interactions in outer-sphere electron transfer (OS-ET), a cornerstone elementary electrochemical reaction, at graphene as-grown on a copper electrode. Using scanning electrochemical cell microscopy, and co-located structural microscopy, the classical hexaamineruthenium (III/II) couple shows the ET kinetics trend: monolayer > bilayer > multilayer graphene. This trend is rationalized quantitatively through the development of rate theory, using the Schmickler-Newns-Anderson model Hamiltonian for ET, with the explicit incorporation of electrostatic interactions in the double layer, and parameterized using constant potential density functional theory calculations. The ET mechanism is predominantly adiabatic; the addition of subsequent graphene layers increases the contact potential, producing an increase in the effective barrier to ET at the electrode/electrolyte interface.
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Journal
Nature CommunicationsVolume
12Issue
1Article number
ARTN 7110Pagination
1 - 11Publisher
Nature Publishing GroupLocation
London, Eng.Publisher DOI
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2041-1723eISSN
2041-1723Language
EnglishPublication classification
C1.1 Refereed article in a scholarly journalUsage metrics
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