Article ID Journal Published Year Pages File Type
1450771 Acta Materialia 2007 7 Pages PDF
Abstract

Nanocrystalline MgH2 with fine and evenly dispersed Nb hydride was prepared by ball milling a mixture of MgH2 and 1 mol.% NbF5. This NbH-catalyzed MgH2 desorbed 6.3 wt.% H2 in 15 min and absorbed more than 90% of its initial hydrogen capacity within 5 min at 573 K. Moreover, this fast sorption kinetics was maintained after 10 cycles. Based on X-ray diffraction and transmission electron microscopy/energy-dispersive spectroscopy analyses, it is suggested that NbF5 melts during high-energy ball milling and this promotes the formation of extremely fine, film-like Nb hydride preferentially along the grain boundaries of nanocrystalline MgH2 by a liquid/solid reaction. This unique nanostructured Nb hydride is believed to suppress the grain growth of MgH2 quite effectively and thus maintain its initial catalytic effect throughout repeated hydrogenation–dehydrogenation cycles.

Related Topics
Physical Sciences and Engineering Materials Science Ceramics and Composites
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