The Ca(BH4)2–MgH2 composite system represents a promising candidate for mobile hydrogen storage due to a 10.5 wt % theoretical hydrogen storage capacity and an estimated equilibrium temperature lower than 160 °C. For this system, the reversibility was achieved without further addition of additives. In this study, the decomposition path of the Ca(BH4)2 + MgH2 composite system is investigated in detail by in situ synchrotron radiation powder X-ray diffraction and differential scanning calorimetry combined with thermogravimetry. The sorption properties are analyzed by volumetric measurements. 11B{1H} solid state magic angle spinning–nuclear magnetic resonance was employed for the characterization of the final amorphous or nanocrystalline boron-based decomposition products. This study shows that the intermediate formation of Ca4Mg3H14 upon dehydrogenation of the Ca(BH4)2–MgH2 composite system is not a necessary step, and its presence can be adjusted modifying the preparation procedure. Moreover, the d-value mismatch calculated for the {111}CaB6/{1011}Mg plane pair is the lowest among the other plane pairs considered in the system. The mismatch in the third direction between CaB6 and Mg is also extremely good. These findings propose Mg as a supporter of the heterogeneous nucleation of CaB6 during decomposition of the Ca(BH4)2 + MgH2 composite system.

Ca(BH4)2 + MgH2: Desorption Reaction and Role of Mg on Its Reversibility / Bonatto Minella, C; Pistidda, C; Garroni, Sebastiano; Nolis, P; Dolors Baró, M; Gutfleisch, O; Klassen, T; Bormann, R; Dornheim, M.. - In: JOURNAL OF PHYSICAL CHEMISTRY. C.. - ISSN 1932-7455. - 117:(2013), pp. 3846-3852. [10.1021/jp312271s]

Ca(BH4)2 + MgH2: Desorption Reaction and Role of Mg on Its Reversibility

GARRONI, Sebastiano;
2013-01-01

Abstract

The Ca(BH4)2–MgH2 composite system represents a promising candidate for mobile hydrogen storage due to a 10.5 wt % theoretical hydrogen storage capacity and an estimated equilibrium temperature lower than 160 °C. For this system, the reversibility was achieved without further addition of additives. In this study, the decomposition path of the Ca(BH4)2 + MgH2 composite system is investigated in detail by in situ synchrotron radiation powder X-ray diffraction and differential scanning calorimetry combined with thermogravimetry. The sorption properties are analyzed by volumetric measurements. 11B{1H} solid state magic angle spinning–nuclear magnetic resonance was employed for the characterization of the final amorphous or nanocrystalline boron-based decomposition products. This study shows that the intermediate formation of Ca4Mg3H14 upon dehydrogenation of the Ca(BH4)2–MgH2 composite system is not a necessary step, and its presence can be adjusted modifying the preparation procedure. Moreover, the d-value mismatch calculated for the {111}CaB6/{1011}Mg plane pair is the lowest among the other plane pairs considered in the system. The mismatch in the third direction between CaB6 and Mg is also extremely good. These findings propose Mg as a supporter of the heterogeneous nucleation of CaB6 during decomposition of the Ca(BH4)2 + MgH2 composite system.
2013
Ca(BH4)2 + MgH2: Desorption Reaction and Role of Mg on Its Reversibility / Bonatto Minella, C; Pistidda, C; Garroni, Sebastiano; Nolis, P; Dolors Baró, M; Gutfleisch, O; Klassen, T; Bormann, R; Dornheim, M.. - In: JOURNAL OF PHYSICAL CHEMISTRY. C.. - ISSN 1932-7455. - 117:(2013), pp. 3846-3852. [10.1021/jp312271s]
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11388/140558
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 35
  • ???jsp.display-item.citation.isi??? 36
social impact