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Au(001) Thin films: impact of structure and mosaicity on the Oxygen Reduction Reaction in Alkaline Medium

Au(001) Thin films: impact of structure and mosaicity on the Oxygen Reduction Reaction in Alkaline Medium
Au(001) Thin films: impact of structure and mosaicity on the Oxygen Reduction Reaction in Alkaline Medium
Au(001) thin films with thickness varying from ca. 25 to 83 nm were deposited on MgO(001) substrates using pulsed laser deposition. Epitaxial growth of (001) Au on the (001) MgO single-crystal substrate was observed with a Au(001)[010]//[010](001)MgO cube-on-cube epitaxial relationship for substrate temperature ≤200 °C. Detailed X-ray reciprocal space mapping (RSM) analysis and atomic force microscopy (AFM) imaging of films with different thicknesses were conducted. There is a nonmonotonic dependence of both the in-plane and out-of-plane lattice parameters with the films’ thickness, while the lateral coherence length increases with the thickness. The maximum tensile strain measured was 0.3% for 65 nm thick Au(001) film. Cyclic voltammetry (CV) in acidic and alkaline media and Pb underpotential deposition (Pb UPD) measurements were used as fingerprints to assess the structure of the surface. All films exhibited the characteristic response of Au(001) single-crystal surfaces, although with some differences in the potential region between 0.7 and 1.2 V vs reversible hydrogen electrode (RHE), which corresponds to the adsorption and partial discharge of OH– anions at the electrode surface. Since epitaxial Au(001) thin films do not lend themselves to steady-state voltammetry with rotating disks or microelectrodes due to their square shape and the insulating nature of MgO substrates, the electrocatalytic activity of the films for the oxygen reduction reaction (ORR) in the alkaline electrolyte was assessed by sampled current voltammetry. It was shown that both the onset potential (Eonset) and the half-wave potential (E1/2) for the ORR do not show any dependence on strain but rather become less negative (more active) with an increase of the lateral coherence length. These data are rationalized in the context of recent density functional theory (DFT) calculations and the mechanisms governing the ORR in alkaline electrolytes.
Au electrode, Au thin film, Au(001) facet, Sampled current voltammetry, coherence length, oxygen reduction reaction, pulsed laser deposition, strain effect
2155-5435
1664–1676
Soares, Cybelle Oliveira
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Buvat, Gaetan
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González Hernández, Yoandris
ffcb31e8-a2b5-4698-b64f-392c142a7bca
Garbarino, Sébastien
75e16010-9067-4920-9acc-d9697fb6fa5d
Duca, Matteo
d0bb05bd-21b0-411b-91d8-99d50cba314b
Ruediger, Andreas
0c3b54c4-0759-481a-943d-2574b86a8aa1
Denuault, Guy
5c76e69f-e04e-4be5-83c5-e729887ffd4e
Tavares, Ana
b3dfb24d-4a0e-4c40-93e4-c8c649bef873
Guay, Daniel
75ae64d9-583c-4d46-b5c1-607bdc36a8b0
Soares, Cybelle Oliveira
e8694831-538f-42d5-9bd9-4dcb580e13df
Buvat, Gaetan
5f09ac8b-9443-4539-a09c-4942e7627719
González Hernández, Yoandris
ffcb31e8-a2b5-4698-b64f-392c142a7bca
Garbarino, Sébastien
75e16010-9067-4920-9acc-d9697fb6fa5d
Duca, Matteo
d0bb05bd-21b0-411b-91d8-99d50cba314b
Ruediger, Andreas
0c3b54c4-0759-481a-943d-2574b86a8aa1
Denuault, Guy
5c76e69f-e04e-4be5-83c5-e729887ffd4e
Tavares, Ana
b3dfb24d-4a0e-4c40-93e4-c8c649bef873
Guay, Daniel
75ae64d9-583c-4d46-b5c1-607bdc36a8b0

Soares, Cybelle Oliveira, Buvat, Gaetan, González Hernández, Yoandris, Garbarino, Sébastien, Duca, Matteo, Ruediger, Andreas, Denuault, Guy, Tavares, Ana and Guay, Daniel (2022) Au(001) Thin films: impact of structure and mosaicity on the Oxygen Reduction Reaction in Alkaline Medium. ACS Catalysis, 12 (3), 1664–1676. (doi:10.1021/acscatal.1c04407).

Record type: Article

Abstract

Au(001) thin films with thickness varying from ca. 25 to 83 nm were deposited on MgO(001) substrates using pulsed laser deposition. Epitaxial growth of (001) Au on the (001) MgO single-crystal substrate was observed with a Au(001)[010]//[010](001)MgO cube-on-cube epitaxial relationship for substrate temperature ≤200 °C. Detailed X-ray reciprocal space mapping (RSM) analysis and atomic force microscopy (AFM) imaging of films with different thicknesses were conducted. There is a nonmonotonic dependence of both the in-plane and out-of-plane lattice parameters with the films’ thickness, while the lateral coherence length increases with the thickness. The maximum tensile strain measured was 0.3% for 65 nm thick Au(001) film. Cyclic voltammetry (CV) in acidic and alkaline media and Pb underpotential deposition (Pb UPD) measurements were used as fingerprints to assess the structure of the surface. All films exhibited the characteristic response of Au(001) single-crystal surfaces, although with some differences in the potential region between 0.7 and 1.2 V vs reversible hydrogen electrode (RHE), which corresponds to the adsorption and partial discharge of OH– anions at the electrode surface. Since epitaxial Au(001) thin films do not lend themselves to steady-state voltammetry with rotating disks or microelectrodes due to their square shape and the insulating nature of MgO substrates, the electrocatalytic activity of the films for the oxygen reduction reaction (ORR) in the alkaline electrolyte was assessed by sampled current voltammetry. It was shown that both the onset potential (Eonset) and the half-wave potential (E1/2) for the ORR do not show any dependence on strain but rather become less negative (more active) with an increase of the lateral coherence length. These data are rationalized in the context of recent density functional theory (DFT) calculations and the mechanisms governing the ORR in alkaline electrolytes.

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Au(001)_version15 - Accepted Manuscript
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Accepted/In Press date: 13 January 2022
Published date: 4 February 2022
Additional Information: Funding Information: This work was supported by the Natural Sciences and Engineering Research Council of Canada (NSERC, Strategic Partnership program). C.O.S. acknowledges the FRQNT funding by means of the PBEEE merit scholarship and an internship received from the Engineered Nickel Catalysts for Electrochemical Clean Energy project administered from Queen’s University and supported by Grant no. RGPNM 477963-2015 under the NSERC Discovery Frontiers Program. Copyright © 2022, American Chemical Society
Keywords: Au electrode, Au thin film, Au(001) facet, Sampled current voltammetry, coherence length, oxygen reduction reaction, pulsed laser deposition, strain effect

Identifiers

Local EPrints ID: 454477
URI: http://eprints.soton.ac.uk/id/eprint/454477
ISSN: 2155-5435
PURE UUID: 72055ea6-ebcd-4abf-8e87-0f9f92ae49c9
ORCID for Guy Denuault: ORCID iD orcid.org/0000-0002-8630-9492

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Date deposited: 10 Feb 2022 17:44
Last modified: 17 Mar 2024 07:05

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Contributors

Author: Cybelle Oliveira Soares
Author: Gaetan Buvat
Author: Yoandris González Hernández
Author: Sébastien Garbarino
Author: Matteo Duca
Author: Andreas Ruediger
Author: Guy Denuault ORCID iD
Author: Ana Tavares
Author: Daniel Guay

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