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Volume 210, 2018
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Electrochemistry at a single nanoparticle: from bipolar regime to tunnelling

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Abstract

This paper is concerned with long-distance interactions between an unbiased metal nanoparticle (NP) and a nanoelectrode employed as a tip in the scanning electrochemical microscope (SECM). A NP immobilized on the inert substrate acts as a bipolar electrode, producing positive SECM feedback. The tip current magnitude depends strongly on the ratio of the particle and tip radii and the heterogeneous charge-transfer kinetics. The onset of electron tunneling was observed at very short separation distances (<2–3 nm) at which the NP behaves as a part of the tip electrode. The rate constant of the electron-transfer (ET) or electrocatalytic reaction at the NP can be extracted from either feedback or tunneling current. The tunneling mode of SECM can be used to investigate heterogeneous reactions occurring at a single NP without making an ohmic contact with it. This technique can also help elucidate nanoparticle/electrode interactions in various electrochemical systems ranging from NPs immobilized on the electrode surface to nanoimpact collision events.

Graphical abstract: Electrochemistry at a single nanoparticle: from bipolar regime to tunnelling

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Publication details

The article was received on 19 Feb 2018, accepted on 29 Mar 2018 and first published on 06 Jul 2018


Article type: Paper
DOI: 10.1039/C8FD00041G
Citation: Faraday Discuss., 2018,210, 173-188
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    Electrochemistry at a single nanoparticle: from bipolar regime to tunnelling

    T. Sun, D. Wang and Michael V. Mirkin, Faraday Discuss., 2018, 210, 173
    DOI: 10.1039/C8FD00041G

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