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Metallographic and numerical studies of the role of catalyst particles of MgH2-Mg system

TitleMetallographic and numerical studies of the role of catalyst particles of MgH2-Mg system
Publication TypeArticolo su Rivista peer-reviewed
Year of Publication2010
AuthorsCelino, M., Montone Amelia, Cleri F., Aurora A., Mirabile Gattia Daniele, Giusepponi S., and Antisari M.V.
JournalDefect and Diffusion Forum
Volume297-301
Pagination263-268
ISBN Number3908451809; 9783908451808
ISSN10120386
KeywordsAb initio, Ab initio molecular dynamics, Ab initio molecular dynamics simulation, Ab-initio, Ab-initio molecular dynamics, Absorption and desorptions, Atomic levels, Atoms, Ball milling, Binding energy, Catalyst particles, Catalysts, Characterization, Deformation, Desorption, Diffusion in solids, Dynamics, Energy storage, Experimental conditions, Experimental methods, Heat transfer, Heavy metal catalysts, Heavy metals, High capacity, High operating temperature, Hydrides, Hydrogen, Hydrogen atoms, Hydrogen storage, Low costs, Low voltages, Magnesium, Magnesium hydride, Mass transfer, Metallography, Microscopic characterization, molecular dynamics, Nano-structuring, Nucleation, Nucleation sites, Numerical studies, Partial desorption, Phase transformation, Powder samples, Promising materials, Reaction kinetics, Scanning electron microscopy, SEM, SEM observation
Abstract

Magnesium is one of the most promising materials for hydrogen storage due to its high capacity and low cost. Unfortunately, practical applications are for the moment limited by the slow kinetics and the high operating temperature. Nanostructuring magnesium hydride MgH2, generally by ball milling, introduces plastic deformations and catalysts that highly enhances the H 2 absorption and desorption. However a fundamental understanding of the role played by catalysts and interfaces in MgH2 is still lacking. Microscopic characterization of MgH2-Mg system with and without heavy metal catalysts, is achieved by combining accurate SEM observations of samples after partial desorption process and atomic level ab-initio molecular dynamics simulations of MgH2-Mg interfaces. The experimental method is based on low voltage SEM observations of cross sectional powder samples, prepared by a new specific metallographic process. Identification of nucleation sites of the sorption reaction and their correlation with the presence of catalyst particles is achieved by suitable experimental conditions. Moreover ab-initio molecular dynamics clarifies the interplay of interfaces and the deformations induced during desorption by the presence of catalysts that are able to lower binding energies and free hydrogen atoms toward interfaces. Both approaches confirm and characterize the nucleation step in the catalysts driven phase transformation. © (2010) Trans Tech Publications.

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URLhttps://www.scopus.com/inward/record.uri?eid=2-s2.0-77952270736&doi=10.4028%2fwww.scientific.net%2fDDF.297-301.263&partnerID=40&md5=adf66a68ca463165877914e2f12a9701
DOI10.4028/www.scientific.net/DDF.297-301.263
Citation KeyCelino2010263