Daviddi, Enrico, Gonos, Katerina, Colburn, Alex W., Bentley, Cameron Luke and Unwin, Patrick R. (2019) Scanning electrochemical cell microscopy (SECCM) chronopotentiometry : development and applications in electroanalysis and electrocatalysis. Analytical Chemistry, 91 (14). pp. 9229-9237. doi:10.1021/acs.analchem.9b02091

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Abstract

Scanning electrochemical cell microscopy (SECCM) has been applied for nanoscale (electro)activity mapping in a range of electrochemical systems but so far has almost exclusively been performed in controlled-potential (amperometric/voltammetric) modes. Herein, we consider the use of SECCM operated in a controlled-current (galvanostatic or chronopotentiometric) mode, to synchronously obtain spatially resolved electrode potential (i.e., electrochemical activity) and topographical “maps”. This technique is first applied, as proof of concept, to study the electrochemically reversible [Ru(NH3)6]3+/2+ electron transfer process at a glassy carbon electrode surface, where the experimental data are in good agreement with well-established chronopotentiometric theory under quasi-radial diffusion conditions. The [Ru(NH3)6]3+/2+ process has also been imaged at “aged” highly ordered pyrolytic graphite (HOPG), where apparently enhanced electrochemical activity is measured at the edge plane relative to the basal plane surface, consistent with potentiostatic measurements. Finally, chronopotentiometric SECCM has been employed to benchmark a promising electrocatalytic system, the hydrogen evolution reaction (HER) at molybdenum disulfide (MoS2), where higher electrocatalytic activity (i.e., lower overpotential at a current density of 2 mA cm–2) is observed at the edge plane compared to the basal plane surface. These results are in excellent agreement with previous controlled-potential SECCM studies, confirming the viability of the technique and thereby opening up new possibilities for the use of chronopotentiometric methods for quantitative electroanalysis at the nanoscale, with promising applications in energy storage (battery) studies, electrocatalyst benchmarking, and corrosion research.

Item Type:	Journal Article
Subjects:	Q Science > QD Chemistry
Divisions:	Faculty of Science > Chemistry
SWORD Depositor:	Library Publications Router
Library of Congress Subject Headings (LCSH):	Chemistry, Analytic, Nanoscience
Journal or Publication Title:	Analytical Chemistry
Publisher:	American Chemical Society
ISSN:	0003-2700
Official Date:	18 June 2019
Dates:	Date Event 18 June 2019 Published 18 June 2019 Accepted
Volume:	91
Number:	14
Page Range:	pp. 9229-9237
DOI:	10.1021/acs.analchem.9b02091
Status:	Peer Reviewed
Publication Status:	Published
Publisher Statement:	“This document is the Accepted Manuscript version of a Published Work that appeared in final form in Analytical Chemistry, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see [insert ACS Articles on Request author-directed link to Published Work, see http://pubs.acs.org/page/policy/articlesonrequest/index.html].”
Access rights to Published version:	Restricted or Subscription Access
Copyright Holders:	Copyright © 2019 American Chemical Society
RIOXX Funder/Project Grant:	Project/Grant ID RIOXX Funder Name Funder ID UNSPECIFIED Lubrizol http://dx.doi.org/10.13039/100007036 UNSPECIFIED Warwick Collaborative Postgraduate Research Scheme UNSPECIFIED UNSPECIFIED Ramsay Memorial Fellowships Trust, University College London http://dx.doi.org/10.13039/501100000685 UNSPECIFIED Wolfson Foundation http://dx.doi.org/10.13039/501100001320

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