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Sampled current voltammetry for kinetic studies on materials unsuitable for rotating discs or microelectrodes: application to the oxygen reduction reaction in acidic medium

Sampled current voltammetry for kinetic studies on materials unsuitable for rotating discs or microelectrodes: application to the oxygen reduction reaction in acidic medium
Sampled current voltammetry for kinetic studies on materials unsuitable for rotating discs or microelectrodes: application to the oxygen reduction reaction in acidic medium

Herein, sampled current voltammetry (SCV) is exploited to study the kinetics of electrochemical reactions with electrode materials that are unsuitable for rotating disc or microelectrode experiments. The approach described opens up the possibility of assessing the electrocatalytic activity of films produced by high throughput deposition techniques, especially conducting films formed on insulators. This is particularly valuable for testing novel oxygen reduction or oxygen evolution catalysts. SCV is a transient technique, yet for processes affected by mass transport, it produces sigmoidal current-voltage curves, which can be analysed as conventional steady state voltammograms. Selecting different sampling times affords a range of mass transfer coefficients and this is particularly useful to determine kinetic parameters. The applicability of SCV is first assessed with the fast electron transfer between ferri and ferrocyanide ions and an excellent agreement between the SCV and RDE methods is found. Then, SCV is used to investigate the oxygen reduction reaction (ORR) on a stationary polycrystalline Pt disc, on a polycrystalline Pt foil and on a thin Pt film orientated in the (110) direction. The results are systematically compared with those from a rotated polycrystalline Pt disc. Importantly, the sampled current voltammograms (SCVs) are found to be sufficiently sensitive to reveal differences in electrocatalytic activity between the Pt electrodes and between different sulfate concentrations. The technique is thus well adapted to probing variations in catalytic activity due to surface structure or interactions between solution species and surface sites. For polycrystalline Pt, the ORR kinetic parameters obtained from the Koutecký-Levich (K-L) analysis of the SCVs are in good agreement with those obtained with the RDE. Overall, the sampled current voltammetry approach reported here provides a valuable alternative to steady state voltammetry, and it is particularly suited to assess the electrocatalytic properties of surfaces where epitaxial thin film electrodes are grown on insulating substrates. The methodology could easily be extended to other substrates such as catalysts deposited on gas diffusion electrodes.

Crystallographic orientation, Oxygen reduction reaction, Platinum, Sampled current voltammetry, Specific adsorption
0013-4686
Soares, Cybelle Oliveira
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Rodriguez Martinez, Oliver
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Buvat, Gaetan
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Duca, Matteo
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Garbarino, Sébastien
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Guay, Daniel
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Denuault, Guy
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Tavares, Ana C.
b3dfb24d-4a0e-4c40-93e4-c8c649bef873
Soares, Cybelle Oliveira
e8694831-538f-42d5-9bd9-4dcb580e13df
Rodriguez Martinez, Oliver
db4ea889-5239-4b2b-a744-7c953461b13f
Buvat, Gaetan
5f09ac8b-9443-4539-a09c-4942e7627719
Duca, Matteo
d0bb05bd-21b0-411b-91d8-99d50cba314b
Garbarino, Sébastien
75e16010-9067-4920-9acc-d9697fb6fa5d
Guay, Daniel
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Denuault, Guy
5c76e69f-e04e-4be5-83c5-e729887ffd4e
Tavares, Ana C.
b3dfb24d-4a0e-4c40-93e4-c8c649bef873

Soares, Cybelle Oliveira, Rodriguez Martinez, Oliver, Buvat, Gaetan, Duca, Matteo, Garbarino, Sébastien, Guay, Daniel, Denuault, Guy and Tavares, Ana C. (2020) Sampled current voltammetry for kinetic studies on materials unsuitable for rotating discs or microelectrodes: application to the oxygen reduction reaction in acidic medium. Electrochimica Acta, 362, [136946]. (doi:10.1016/j.electacta.2020.136946).

Record type: Article

Abstract

Herein, sampled current voltammetry (SCV) is exploited to study the kinetics of electrochemical reactions with electrode materials that are unsuitable for rotating disc or microelectrode experiments. The approach described opens up the possibility of assessing the electrocatalytic activity of films produced by high throughput deposition techniques, especially conducting films formed on insulators. This is particularly valuable for testing novel oxygen reduction or oxygen evolution catalysts. SCV is a transient technique, yet for processes affected by mass transport, it produces sigmoidal current-voltage curves, which can be analysed as conventional steady state voltammograms. Selecting different sampling times affords a range of mass transfer coefficients and this is particularly useful to determine kinetic parameters. The applicability of SCV is first assessed with the fast electron transfer between ferri and ferrocyanide ions and an excellent agreement between the SCV and RDE methods is found. Then, SCV is used to investigate the oxygen reduction reaction (ORR) on a stationary polycrystalline Pt disc, on a polycrystalline Pt foil and on a thin Pt film orientated in the (110) direction. The results are systematically compared with those from a rotated polycrystalline Pt disc. Importantly, the sampled current voltammograms (SCVs) are found to be sufficiently sensitive to reveal differences in electrocatalytic activity between the Pt electrodes and between different sulfate concentrations. The technique is thus well adapted to probing variations in catalytic activity due to surface structure or interactions between solution species and surface sites. For polycrystalline Pt, the ORR kinetic parameters obtained from the Koutecký-Levich (K-L) analysis of the SCVs are in good agreement with those obtained with the RDE. Overall, the sampled current voltammetry approach reported here provides a valuable alternative to steady state voltammetry, and it is particularly suited to assess the electrocatalytic properties of surfaces where epitaxial thin film electrodes are grown on insulating substrates. The methodology could easily be extended to other substrates such as catalysts deposited on gas diffusion electrodes.

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20201001_Soares et al_Manuscript_accepted manuscript for Pure - Accepted Manuscript
Restricted to Repository staff only until 27 August 2021.
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Accepted/In Press date: 12 August 2020
e-pub ahead of print date: 27 August 2020
Published date: 1 December 2020
Keywords: Crystallographic orientation, Oxygen reduction reaction, Platinum, Sampled current voltammetry, Specific adsorption

Identifiers

Local EPrints ID: 444531
URI: http://eprints.soton.ac.uk/id/eprint/444531
ISSN: 0013-4686
PURE UUID: 2e51a083-f368-4c91-b1e2-d3bc57f643b5
ORCID for Guy Denuault: ORCID iD orcid.org/0000-0002-8630-9492

Catalogue record

Date deposited: 23 Oct 2020 16:30
Last modified: 18 Feb 2021 16:41

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Contributors

Author: Cybelle Oliveira Soares
Author: Oliver Rodriguez Martinez
Author: Gaetan Buvat
Author: Matteo Duca
Author: Sébastien Garbarino
Author: Daniel Guay
Author: Guy Denuault ORCID iD
Author: Ana C. Tavares

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