Sorption properties and reversibility of Ti(IV) and Nb(V)-fluoride doped-Ca(BH4)2-MgH2 system
Bonatto Minella, Christian (Institut für Festkörper- und Werkstofforschung Dresden)
Garroni, Sebastiano (Università degli Studi di Sassari. Dipartimento di Chimica e Farmacia)
Pistidda, Claudio (Helmholtz-Zentrum Geesthacht. Das Institut für Werkstoffforschung)
Baró, M. D.. (Universitat Autònoma de Barcelona. Departament de Física)
Gutfleisch, O (Technische Universität Darmstadt. Fachgebiete Materialwissenschaft)
Klassen, Thomas (Helmholtz-Zentrum Geesthacht. Das Institut für Werkstoffforschung)
Dornheim, Martin (Helmholtz-Zentrum Geesthacht. Das Institut für Werkstoffforschung)

Data:	2015
Resum:	In the last decade, alkaline and alkaline earth metal tetrahydroborates have been the focuses of the research due to their high gravimetric and volumetric hydrogen densities. Among them, Ca(BH4)2 and the Ca(BH4)2 + MgH2 reactive hydride composite (RHC), were calculated to have the ideal thermodynamic properties which fall within the optimal range for mobile applications. In this study, the addition of NbF5 or TiF4 to the Ca(BH4)2 + MgH2 reactive hydride composite system was attempted aiming to obtain a full reversible system with the simultaneous supression of CaB12H12. Structural characterization of the specimens was performed by means of in-situ Synchroton Radiation Power X-ray diffraction (SR-PXD) and 11B {1H} Solid State Magic Angle Spinning-Nuclear Magnetic Resonance (MAS-NMR). The evolution of the chemical state of the Nb- and Ti-based additives was monitored by X-ray Absorption Near Edge Structure (XANES). The addition of NbF5 or TiF4 to the Ca(BH4)2 + MgH2 system have not supressed completely the formation of CaB12H12 and only a slight improvement concerning the reversible reaction was displayed just in the case of Nb-doped composite material.
Nota:	Ajuts: The authors are grateful to the Marie-Curie European Research Training Network (Contract MRTN-CT-2006-03 5366/COSY)
Drets:	Aquest material està protegit per drets d'autor i/o drets afins. Podeu utilitzar aquest material en funció del que permet la legislació de drets d'autor i drets afins d'aplicació al vostre cas. Per a d'altres usos heu d'obtenir permís del(s) titular(s) de drets.
Llengua:	Anglès
Document:	Article ; recerca ; Versió acceptada per publicar
Matèria:	Hydrogen storage ; Transition metal fluorides ; Tetrahydroborate ; Ins-situ Synchronton Radiation Powder X-ray diffraction (SR-PXD) ; X-ray Absorption Near Edge Structure (XANES) ; 11B {1H} Solid State Magic Angle Spinning-Nuclear Magnetic Resonance (MAS-NMR)
Publicat a:	Journal of alloys and compounds, Vol. 622 (Feb. 2015) , p. 989-994, ISSN 0925-8388

DOI: 10.1016/j.jallcom.2014.11.038

Post-print 26 p, 1.3 MB

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