Du är här

Pressure Effect on the 2NaH+MgB2 Hydrogen Absorption Reaction

Författare:
  • Claudio Pistidda
  • Sebastiano Garroni
  • Christian Bonatto Minella
  • Francesco Dolci
  • Torben R. Jensen
  • Pau Nolis
  • Ulrike Boesenberg
  • Yngve Cerenius
  • Wiebke Lohstroh
  • Maximilian Fichtner
  • Maria Dolores Baro
  • Ruediger Bormann
  • Martin Dornheim
Publiceringsår: 2010
Språk: Engelska
Sidor: 21816-21823
Publikation/Tidskrift/Serie: Journal of Physical Chemistry C
Volym: 114
Nummer: 49
Dokumenttyp: Artikel
Förlag: Amer Chemical Soc

Sammanfattning

The hydrogen absorption mechanism of the 2NaH + MgB2 system has been investigated in detail. Depending on the applied hydrogen pressure, different intermediate phases are observed. In the case of absorption measurements performed under 50 bar of hydrogen pressure, NaBH4 is found not to be formed directly. Instead, first an unknown phase is formed, followed upon further heating by the formation of NaMgH3 and a NaH-NaBH4 molten salt mixture; only at the end after heating to 380 degrees C do the reflections of the crystalline NaBH4 appear. In contrast, measurements performed at lower hydrogen pressure (5 bar of H-2), but under the same temperature conditions, demonstrate that the synthesis of NaBH4 is possible without occurrence of the unknown phase and of NaMgH3. This indicates that the reaction path can be tuned by the applied hydrogen pressure. The formation of a NaH-NaBH4 molten salt mixture is observed also for the measurement performed under 5 bar of hydrogen pressure with the formation of free Mg. However, under this pressure condition the formation of crystalline NaBH4 is observed only during cooling at 367 degrees C. For none of the applied experimental conditions has it been possible to achieve the theoretical gravimetric hydrogen capacity of 7.8 wt %.

Disputation

Nyckelord

  • Physics and Astronomy

Övriga

Published
Yes
  • ISSN: 1932-7447

Box 117, 221 00 LUND
Telefon 046-222 00 00 (växel)
Telefax 046-222 47 20
lu [at] lu [dot] se

 

Fakturaadress: Box 188, 221 00 LUND
Organisationsnummer: 202100-3211
Om webbplatsen