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Nguyen, N. B., Lebon, A., Vega, A. & Mokrani, A. (2012) Improvement of hydrogen uptake in iron and vanadium matrices by doping with 3d atomic impurities. J. Alloy. Compd. 545 19–27.
Added by: Laurent Cournède (2016-03-10 21:28:37) |
| Type de référence: Article DOI: 10.1016/j.jallcom.2012.07.100 Numéro d'identification (ISBN etc.): 0925-8388 Clé BibTeX: Nguyen2012 Voir tous les détails bibliographiques  |
Catégories: PMN Mots-clés: ab-initio, clusters, Computer simulations, density, destabilization, electronic-structure, fukui function, Hydrogen absorbing materials, magnetic-properties, Metals and alloys, pseudopotentials, storage, systems, Transition metal and compounds Créateurs: Lebon, Mokrani, Nguyen, Vega Collection: J. Alloy. Compd. |
Consultations : 1/466
Indice de consultation : 3% Indice de popularité : 0.75% |
| Résumé |
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The insertion of hydrogen in V and Fe has been investigated by means of pseudopotential DFT calculations with localized basis sets. In Fe and V matrices we have replaced the central atom by a transition metal impurity X = Sc, Ti, Cr, Mn, Fe, Co and Ni to study the capacity of the environment to trap hydrogen. The dissolution energy and structural rearrangement upon H uptake at the different sites close to the doping impurity are calculated. Optimal electronic environments for H trapping are also determined through the calculation of the Fukui function. In the V matrix, the insertion of hydrogen is promoted by doping with the two impurities located at the left of V in the Periodical Table, that is, Ti and Sc. In the iron matrix, among the elements at its left in the Periodic Table, only Mn improves the H uptake, whereas doping with V and Ti worsen the capability of absorbing hydrogen. Finally, the H-H interaction is found to be strongly dependent upon the metal-hydrogen interaction. Elements like Mn or Fe which shorten the H-X distance, exhibit a strong 3d TM state-is hydrogen state hybridization that seems to wash out the repulsive H-H Coulomb interaction below the 2.0 angstrom limit. Addition of a small percentage of Fe or Mn in binary bcc alloys (V-Ti) is suggested to locally enhance the H storage capacity. (C) 2012 Elsevier B.V. All rights reserved.
Added by: Laurent Cournède |