Facile preparation of β-/γ-MgH2 nanocomposites under mild conditions and pathways to rapid dehydrogenation

Xiao, X., Liu, Z., Yarahmadi, S. S. and Gregory, D. (2016) Facile preparation of β-/γ-MgH2 nanocomposites under mild conditions and pathways to rapid dehydrogenation. Physical Chemistry Chemical Physics, 18(15), pp. 10492-10498. (doi: 10.1039/C5CP07762A) (PMID:27030171)

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Abstract

A magnesium hydride composite with enhanced hydrogen desorption kinetics can be synthesized via a simple wet chemical route by ball milling MgH2 with LiCl as an additive at room temperature followed by tetrahydrofuran (THF) treatment under an Ar atmosphere. The as-synthesized composite comprises ca. 18 mass% orthorhombic γ-MgH2 and 80 mass% tetragonal β-MgH2 as submicron-sized particles. The β-/γ-MgH2 nanocomposite exhibits a dehydrogenation capacity of 6.6 wt.% and starts to release hydrogen at ~260 °C; ca. 140 °C lower than that of commercial MgH2. The apparent activation energy for dehydrogenation is 115±3 kJ mol-1, which is ca. 46 % lower than that of commercial MgH2. Analysis suggests that the meta-stable γ-MgH2 component either directly dehydrogenates exothermically or first transforms into stable β-MgH2 very close to the dehydrogenation onset. The improved hydrogen release performance can be attributed both to the existence of the MgH2 nanostructure and to the presence of γ-MgH2.

Item Type:Articles
Additional Information:The authors gratefully acknowledge financial support from the University of Glasgow and the National Natural Science Foundation of China (51571179). DHG also thanks the China Scholarship Council for the award of a scholarship to ZL.
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Xiao, Professor Xuezhang and Gregory, Professor Duncan
Authors: Xiao, X., Liu, Z., Yarahmadi, S. S., and Gregory, D.
College/School:College of Science and Engineering > School of Chemistry
Journal Name:Physical Chemistry Chemical Physics
Publisher:Royal Society of Chemistry
ISSN:1463-9076
ISSN (Online):1463-9084
Published Online:22 March 2016
Copyright Holders:Copyright © 2016 Royal Society of Chemistry
First Published:First published in Physical Chemistry Chemical Physics 18(15):10492-10498
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher

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