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dc.contributor.authorDenys, Roman V
dc.contributor.authorYartys, Volodymyr A
dc.contributor.authorGray, Evan MacA
dc.contributor.authorWebb, Colin J
dc.date.accessioned2017-09-13T12:30:35Z
dc.date.available2017-09-13T12:30:35Z
dc.date.issued2015
dc.identifier.issn1996-1073
dc.identifier.doi10.3390/en8043198
dc.identifier.urihttp://hdl.handle.net/10072/124971
dc.description.abstracthis work focused on the high pressure PCT and in situ neutron powder diffraction studies of the LaMg2Ni9-H2 (D2) system at pressures up to 1,000 bar. LaMg2Ni9 alloy was prepared by a powder metallurgy route from the LaNi9 alloy precursor and Mg powder. Two La3−xMgxNi9 samples with slightly different La/Mg ratios were studied, La1.1Mg1.9Ni9 (sample 1) and La0.9Mg2.1Ni9 (sample 2). In situ neutron powder diffraction studies of the La1.09Mg1.91Ni9D9.5 (1) and La0.91Mg2.09Ni9D9.4 (2) deuterides were performed at 25 bar D2 (1) and 918 bar D2 (2). The hydrogenation properties of the (1) and (2) are dramatically different from those for LaNi3. The Mg-containing intermetallics reversibly form hydrides with DHdes = 24.0 kJ/molH2 and an equilibrium pressure of H2 desorption of 18 bar at 20 °C (La1.09Mg1.91Ni9). A pronounced hysteresis of H2 absorption and desorption, ~100 bar, is observed. The studies showed that LaNi5-assisted hydrogenation of MgNi2 in the LaMg2Ni9 hybrid structure takes place. In the La1.09Mg1.91Ni9D9.5 (1) and La0.91Mg2.09Ni9D9.4 (2) (a = 5.263/5.212; c = 25.803/25.71 Å) D atoms are accommodated in both Laves and CaCu5-type slabs. In the LaNi5 CaCu5-type layer, D atoms fill three types of interstices; a deformed octahedron [La2Ni4], and [La(Mg)2Ni2] and [Ni4] tetrahedra. The overall chemical compositions can be presented as LaNi5H5.6/5.0 + 2*MgNi2H1.95/2.2 showing that the hydrogenation of the MgNi2 slab proceeds at mild H2/D2 pressure of just 20 bar. A partial filling by D of the four types of the tetrahedral interstices in the MgNi2 slab takes place, including [MgNi3] and [Mg2Ni2] tetrahedra.
dc.description.peerreviewedYes
dc.languageEnglish
dc.publisherMDPI
dc.relation.ispartofpagefrom3198
dc.relation.ispartofpageto3211
dc.relation.ispartofissue4
dc.relation.ispartofjournalEnergies
dc.relation.ispartofvolume8
dc.subject.fieldofresearchEngineering not elsewhere classified
dc.subject.fieldofresearchEngineering
dc.subject.fieldofresearchPhysical Sciences
dc.subject.fieldofresearchcode099999
dc.subject.fieldofresearchcode09
dc.subject.fieldofresearchcode02
dc.titleLaNi5-Assisted Hydrogenation of MgNi2 in the Hybrid Structures of La1.09Mg1.91Ni9D9.5 and La0.91Mg2.09Ni9D9.4
dc.typeJournal article
dc.type.descriptionC1 - Articles
dc.type.codeC - Journal Articles
dcterms.licensehttp://creativecommons.org/licenses/by/4.0/
dc.description.versionPublished
gro.rights.copyright© 2015 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution license (http://creativecommons.org/licenses/by/4.0/) which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).
gro.hasfulltextFull Text
gro.griffith.authorWebb, Jim J.
gro.griffith.authorGray, Evan M.


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