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Electrochemical_tunneling_through_hBN_combined.pdf (4.46 MB)

Marcus-Hush Theory Revealed by Electron Tunneling Through Hexagonal Boron Nitride

preprint
submitted on 06.08.2019, 19:03 and posted on 08.08.2019, 14:40 by Matěj Velický, Sheng Hu, Colin R. Woods, Peter S. Toth, Viktor Zólyomi, Andre K. Geim, Hector Abruna, Kostya S. Novoselov, Robert A. W. Dryfe
Marcus-Hush theory of electron transfer is one of the pillars of modern electrochemistry with a large body of supporting experimental evidence presented to date. However, some predictions, such as the electrochemical behavior at microdisk electrodes, remain unverified. Herein, we present a study of electron tunneling across a hexagonal boron nitride barrier between a graphite electrode and redox levels in a liquid solution. This was achieved by the fabrication of microdisk electrodes with a typical diameter of 5 µm. Analysis of voltammetric measurements, using two common redox mediators, yielded several electrochemical parameters, including the electron transfer rate constant, limiting current, and transfer coefficient. They show a significant departure from the Butler-Volmer behavior in a clear manifestation of the Marcus-Hush theory of electron transfer. In addition, our system provides a novel experimental platform, which could be applied to address a number of scientific problems such as identification of reaction mechanisms, surface modification, or long-range electron transfer.

History

Email Address of Submitting Author

matej.velicky@manchester.ac.uk

Institution

University of Manchester

Country

United Kingdom

ORCID For Submitting Author

0000-0003-4230-3811

Declaration of Conflict of Interest

No conflict of interest

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Exports