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Surface and Particle-Size Effects on Hydrogen Desorption from Catalyst-Doped MgH2

TitleSurface and Particle-Size Effects on Hydrogen Desorption from Catalyst-Doped MgH2
Publication TypeJournal Article
Year of Publication2012
AuthorsReich JM, Wang LL, Johnson DD
Journal TitleJournal of Physical Chemistry C
Volume116
Pages20315-20320
Date Published09
Type of ArticleArticle
ISBN Number1932-7447
Accession NumberWOS:000309150200024
Keywordsab-initio, dehydrogenation, initio molecular-dynamics, magnesium hydride, metals, sorption kinetics, storage properties, system, total-energy calculations, wave basis-set
Abstract

With their high capacity, light-metal hydrides like MgH2 remain under scrutiny as reversible H-storage materials, especially to develop control of H-desorption properties by decreasing size (ball-milling) and/or adding catalysts. By employing density functional theory and simulated annealing, we study initial H-2 desorption from semi-infinite stepped rutile (110) surface and Mg31H62 nanoclusters, with(out) transition-metal catalyst dopants (Ti or Fe). While Mg31H62 structures are disordered (amorphous), the semi-infinite surfaces and nanoclusters have similar single, double, and triple H-to-metal bond configurations that yield similar H-desorption energies. Hence, there is no size effect on desorption energetics with reduction in sample size, but dopants do reduce the H-desorption energy. All desorption energies are endothermic, in contrast to a recent report.
URL<Go to ISI>://WOS:000309150200024
DOI10.1021/jp304059c
Alternate JournalJ. Phys. Chem. C