The effect of transition metals on hydrogen migration and catalysis in cast Mg-Ni alloys

Cho, Y. H., Aminorroaya, S., Liu, H. K. and Dahle, A. K. (2011) The effect of transition metals on hydrogen migration and catalysis in cast Mg-Ni alloys. International Journal of Hydrogen Energy, 36 8: 4984-4992. doi:10.1016/j.ijhydene.2010.12.090

Author Cho, Y. H.
Aminorroaya, S.
Liu, H. K.
Dahle, A. K.
Title The effect of transition metals on hydrogen migration and catalysis in cast Mg-Ni alloys
Journal name International Journal of Hydrogen Energy   Check publisher's open access policy
ISSN 0360-3199
Publication date 2011-04
Sub-type Article (original research)
DOI 10.1016/j.ijhydene.2010.12.090
Open Access Status
Volume 36
Issue 8
Start page 4984
End page 4992
Total pages 9
Place of publication London, United Kingdom
Publisher Elsevier
Language eng
Formatted abstract
The inexpensive fabrication technique of casting is applied to develop new Mg-Ni based hydrogen storage alloys with improved hydrogen sorption properties. A nanostructured eutectic Mg-Mg2Ni is formed upon solidification which introduces a large area of interfaces along which hydrogen diffusion can occur with high diffusivity. After a few cycles of hydrogenation and dehydrogenation, an ultrafine porous structure formed in the eutectic Mg-Mg2Ni and some cracks developed along the interface between the eutectic and the α-Mg matrix. This indicates that hydrogen atoms introduced into the alloys preferentially migrate along the interfaces in the nanostructured eutectic which enables effective short-range diffusion of hydrogen. Furthermore, transition metals (TMs) such as Nb, Ti and V in the range 240-560 ppm are added directly to molten Mg-10 wt% Ni alloys and are found to form intermetallic compounds with Ni during solidification. The alloys can store 5.6-6.3 wt% hydrogen at 350 °C and 2 MPa. TM-rich intermetallics distributed homogeneously in the cast alloys appear to play a key role in accelerating the nucleation of Mg from MgH2 upon dehydrogenation. This leads to a significant improvement in the hydrogen desorption kinetics.
Keyword Hydrogen storage
Eutectic Mg-Mg2Ni
Porous structure
Transition metal rich intermetallics
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Mechanical & Mining Engineering Publications
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