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Bifunctional versus Defect‐Mediated Effects in Electrocatalytic Methanol Oxidation

The most prominent and intensively studied anode catalyst material for direct methanol oxidation fuel cells consists of a combination of platinum (Pt) and ruthenium (Ru). Classically, their high performance is attributed to a bifunctional reaction mechanism where Ru sites provide oxygen species at l...

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Autores principales: Engstfeld, Albert K., Klein, Jens, Brimaud, Sylvain
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8251818/
https://www.ncbi.nlm.nih.gov/pubmed/33635558
http://dx.doi.org/10.1002/cphc.202000979
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author Engstfeld, Albert K.
Klein, Jens
Brimaud, Sylvain
author_facet Engstfeld, Albert K.
Klein, Jens
Brimaud, Sylvain
author_sort Engstfeld, Albert K.
collection PubMed
description The most prominent and intensively studied anode catalyst material for direct methanol oxidation fuel cells consists of a combination of platinum (Pt) and ruthenium (Ru). Classically, their high performance is attributed to a bifunctional reaction mechanism where Ru sites provide oxygen species at lower overpotential than Pt. In turn, they oxidize the adsorbed carbonaceous reaction intermediates at lower overpotential; among these, the Pt site‐blocking carbon monoxide. We demonstrate that well‐defined Pt modified Ru(0001) single crystal electrodes, with varying Pt contents and different local PtRu configurations at the surface, are unexpectedly inactive for the methanol oxidation reaction. This observation stands in contradiction with theoretical predictions and the concept of bifunctional catalysis for this reaction. Instead, we suggest that pure Pt defect sites play a more critical role than bifunctional defect sites on the electrodes investigated in this work.
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spelling pubmed-82518182021-07-07 Bifunctional versus Defect‐Mediated Effects in Electrocatalytic Methanol Oxidation Engstfeld, Albert K. Klein, Jens Brimaud, Sylvain Chemphyschem Communications The most prominent and intensively studied anode catalyst material for direct methanol oxidation fuel cells consists of a combination of platinum (Pt) and ruthenium (Ru). Classically, their high performance is attributed to a bifunctional reaction mechanism where Ru sites provide oxygen species at lower overpotential than Pt. In turn, they oxidize the adsorbed carbonaceous reaction intermediates at lower overpotential; among these, the Pt site‐blocking carbon monoxide. We demonstrate that well‐defined Pt modified Ru(0001) single crystal electrodes, with varying Pt contents and different local PtRu configurations at the surface, are unexpectedly inactive for the methanol oxidation reaction. This observation stands in contradiction with theoretical predictions and the concept of bifunctional catalysis for this reaction. Instead, we suggest that pure Pt defect sites play a more critical role than bifunctional defect sites on the electrodes investigated in this work. John Wiley and Sons Inc. 2021-04-06 2021-05-05 /pmc/articles/PMC8251818/ /pubmed/33635558 http://dx.doi.org/10.1002/cphc.202000979 Text en © 2021 The Authors. ChemPhysChem published by Wiley-VCH GmbH https://creativecommons.org/licenses/by-nc/4.0/This is an open access article under the terms of the http://creativecommons.org/licenses/by-nc/4.0/ (https://creativecommons.org/licenses/by-nc/4.0/) License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.
spellingShingle Communications
Engstfeld, Albert K.
Klein, Jens
Brimaud, Sylvain
Bifunctional versus Defect‐Mediated Effects in Electrocatalytic Methanol Oxidation
title Bifunctional versus Defect‐Mediated Effects in Electrocatalytic Methanol Oxidation
title_full Bifunctional versus Defect‐Mediated Effects in Electrocatalytic Methanol Oxidation
title_fullStr Bifunctional versus Defect‐Mediated Effects in Electrocatalytic Methanol Oxidation
title_full_unstemmed Bifunctional versus Defect‐Mediated Effects in Electrocatalytic Methanol Oxidation
title_short Bifunctional versus Defect‐Mediated Effects in Electrocatalytic Methanol Oxidation
title_sort bifunctional versus defect‐mediated effects in electrocatalytic methanol oxidation
topic Communications
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8251818/
https://www.ncbi.nlm.nih.gov/pubmed/33635558
http://dx.doi.org/10.1002/cphc.202000979
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