Catalytic effect of niobium oxide on hydrogen storage properties of mechanically ball milled MgH2

Nobuko Hanada, Takayuki Ichikawa, Hironobu Fujii

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

We examined a catalytic effect of niobium oxide (Nb2O5) on the hydrogen storage properties of MgH2 prepared by mechanical ball milling method. The MgH2 composite doped with 1 mol% Nb2O5 by ball milling for 20 h desorbed hydrogen up to ∼6 mass% in the temperature range from 200 to 250 °C at the heating rate of 5 °C/min under a purified helium flow. After dehydrogenation at 200 °C, the product showed remarkable hydrogen absorption kinetics. A large amount of gaseous hydrogen up to ∼4.5 mass% was absorbed even at room temperature under 1 MPa hydrogen pressure within 15 s and finally its capacity reached up to 5 mass%. Furthermore, the valence state of Nb2O5 doped in MgH2 was examined by X-ray absorption near edge structure (XANES) measurement. The results indicated that additive Nb2O5 was reduced by MgH2 during mechanical milling. This suggests that the Nb compound, in which the valence state of Nb atom is less than 5+, acts as a catalyst for the hydrogen absorbing/desorbing kinetics.

Original languageEnglish
Pages (from-to)49-50
Number of pages2
JournalPhysica B: Condensed Matter
Volume383
Issue number1
DOIs
Publication statusPublished - 2006 Aug 15
Externally publishedYes

Fingerprint

Niobium oxide
niobium oxides
Hydrogen storage
balls
Hydrogen
hydrogen
Ball milling
Helium
Kinetics
valence
X ray absorption
Dehydrogenation
Heating rate
kinetics
dehydrogenation
Atoms
Temperature
helium
Catalysts
Composite materials

Keywords

  • Catalytic effect
  • Hydrogen storage materials
  • Magnesium hydride
  • Mechanical milling

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics

Cite this

Catalytic effect of niobium oxide on hydrogen storage properties of mechanically ball milled MgH2 . / Hanada, Nobuko; Ichikawa, Takayuki; Fujii, Hironobu.

In: Physica B: Condensed Matter, Vol. 383, No. 1, 15.08.2006, p. 49-50.

Research output: Contribution to journalArticle

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AB - We examined a catalytic effect of niobium oxide (Nb2O5) on the hydrogen storage properties of MgH2 prepared by mechanical ball milling method. The MgH2 composite doped with 1 mol% Nb2O5 by ball milling for 20 h desorbed hydrogen up to ∼6 mass% in the temperature range from 200 to 250 °C at the heating rate of 5 °C/min under a purified helium flow. After dehydrogenation at 200 °C, the product showed remarkable hydrogen absorption kinetics. A large amount of gaseous hydrogen up to ∼4.5 mass% was absorbed even at room temperature under 1 MPa hydrogen pressure within 15 s and finally its capacity reached up to 5 mass%. Furthermore, the valence state of Nb2O5 doped in MgH2 was examined by X-ray absorption near edge structure (XANES) measurement. The results indicated that additive Nb2O5 was reduced by MgH2 during mechanical milling. This suggests that the Nb compound, in which the valence state of Nb atom is less than 5+, acts as a catalyst for the hydrogen absorbing/desorbing kinetics.

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