| DOI | Trouver le DOI : https://doi.org/10.1021/nn4019009 |
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| Auteur | Rechercher : Prabhudev, Sagar; Rechercher : Bugnet, Matthieu; Rechercher : Bock, Christina1; Rechercher : Botton, Gianluigi A. |
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| Affiliation | - Conseil national de recherches du Canada. Énergie, les mines et l'environnement
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| Format | Texte, Article |
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| Sujet | Aberration-corrected scanning transmission electron microscopies; Compositional analysis; Enhanced catalytic activity; Lattice strain; Nanocatalysts; Oxygen reduction reaction; Scanning transmission electron microscopy; Two Dimensional (2 D); Atoms; Catalyst activity; Degradation; Durability; Electrolytic reduction; Energy dispersive spectroscopy; Proton exchange membrane fuel cells (PEMFC); Shells (structures); Surface relaxation; Transmission electron microscopy; Two dimensional; X ray diffraction; Platinum |
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| Résumé | Fine-tuning nanocatalysts to enhance their catalytic activity and durability is crucial to commercialize proton exchange membrane fuel cells. The structural ordering and time evolution of ordered Pt3Fe2 intermetallic core-shell nanocatalysts for the oxygen reduction reaction that exhibit increased mass activity (228%) and an enhanced catalytic activity (155%) compared to Pt/C has been quantified using aberration-corrected scanning transmission electron microscopy. These catalysts were found to exhibit a static core-dynamic shell regime wherein, despite treating over 10 000 cycles, there is negligible decrease (9%) in catalytic activity and the ordered Pt 3Fe2 core remained virtually intact while the Pt shell suffered a continuous enrichment. The existence of this regime was further confirmed by X-ray diffraction and the compositional analyses using energy-dispersive spectroscopy. With atomic-scale two-dimensional (2-D) surface relaxation mapping, we demonstrate that the Pt atoms on the surface are slightly relaxed with respect to bulk. The cycled nanocatalysts were found to exhibit a greater surface relaxation compared to noncycled catalysts. With 2-D lattice strain mapping, we show that the particle was about -3% strained with respect to pure Pt. While the observed enhancement in their activity is ascribed to such a strained lattice, our findings on the degradation kinetics establish that their extended catalytic durability is attributable to a sustained atomic order. |
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| Date de publication | 2013-06-17 |
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| Dans | |
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| Langue | anglais |
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| Publications évaluées par des pairs | Oui |
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| Numéro NPARC | 21270349 |
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| Exporter la notice | Exporter en format RIS |
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| Signaler une correction | Signaler une correction (s'ouvre dans un nouvel onglet) |
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| Identificateur de l’enregistrement | 747146e2-9b5a-4b16-91f0-23ba20313fb7 |
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| Enregistrement créé | 2014-02-04 |
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| Enregistrement modifié | 2020-04-22 |
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