| DOI | Trouver le DOI : https://doi.org/10.1016/j.actamat.2012.06.009 |
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| Auteur | Rechercher : Tan, XueHai1; Rechercher : Zahiri, Beniamin; Rechercher : Holt, Chris M. B.1; Rechercher : Kubis, Alan1; Rechercher : Mitlin, David1 |
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| Affiliation | - Conseil national de recherches du Canada. Technologies de sécurité et de rupture
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| Format | Texte, Article |
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| Sujet | Hydrogen storage; Magnesium hydride; TEM; Microstructure; Catalyst |
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| Résumé | Magnesium hydride combined with a new bimetallic Nb–V catalyst displays remarkably rapid and stable low temperature (200 °C) hydrogen storage kinetics, even after 500 full volumetric absorption/desorption cycles. The system is also able to fairly rapidly absorb hydrogen at room temperature at a pressure of 1 bar. This unprecedented absorption behavior was demonstrated for 20 cycles. We employed extensive cryo-stage transmission electron microscopy (TEM) analysis on fully and partially sorbed materials to provide insight into the rapid Mg to MgH2 phase transformation. After extended cycling of what was initially a 1.5 μm thick fully dense alloy film, the sample structure becomes analogous to that of a weakly agglomerated nanocomposite powder. The cycled Mg–V–Nb structure consists of a dense distribution of catalytic Nb–V nanocrystallites covering the surfaces of larger Mg and MgH2 particles. The partially absorbed 20 °C and 200 °C microstructures both show this morphology. TEM results combined with Johnson–Mehl–Avrami-type kinetic analysis point to the surface catalyst distribution and stability against coarsening as being a key influence on the two-stage hydriding kinetics. Remarkably, the mean size of the Nb0.5V0.5H nanocrystallites stays essentially invariant throughout cycling; it is 3 nm after 45 cycles and 4 nm after 500 cycles. A mechanistic description is provided for the cycling-induced microstructural evolution in the ternary alloy as well as in the binary baselines. |
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| Date de publication | 2012-08-27 |
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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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| Identificateur | S1359645412003710 |
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| Numéro NPARC | 21268616 |
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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 | b2584010-fbe6-4fd1-834c-c0fa8f58f7ef |
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| Enregistrement créé | 2013-10-28 |
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| Enregistrement modifié | 2020-04-21 |
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