Synthesis and decomposition mechanisms of ternary Mg2CoH 5 studied using in situ synchrotron X-ray diffraction

Małgorzata Norek , Thomas Kollin Nielsen , Marek Polanski , Izabela Kunce , Tomasz Płociński , Leszek R. Jaroszewicz , Y. Cerenius , Torben René Jensen , Jerzy Bystrzycki


A ternary Mg2CoH5 hydride was synthesized using a novel method that relies on a relatively short mechanical milling time (1 h) of a 2:1 MgH2-Co powder mixture followed by sintering at a sufficiently high hydrogen pressure (>85 bar) and heating from RT to 500 °C. The ternary hydride forms in less than 2.5 h (including the milling time) with a yield of ∼90% at ∼300 °C. The mechanisms of formation and decomposition of ternary Mg2CoH5 were studied in detail using an in situ synchrotron radiation powder X-ray diffraction (SR-PXD). The obtained experimental results are supported by morphological and microstructural investigations performed using SEM and high-resolution STEM. Additionally, thermal effects occurring during the desorption reaction were studied using DSC. The morphology of as-prepared ternary Mg2CoH5 is characterized by the presence of porous particles with various shapes and sizes, which, in fact, are a type of nanocomposite consisting mainly of nanocrystallites with a size of ∼5 nm. Mg2CoH5 decomposes at approximately 300 °C to elemental Mg and Co. Additionally, at approximately 400 °C, MgCo is formed as precipitates inserted into the Mg-Co matrix. During the rehydrogenation of the decomposed residues, prior to the formation of Mg2CoH5, MgH2 appears, which confirms its key role in the synthesis of the ternary Mg2CoH 5. © 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
Author Małgorzata Norek - Wojskowa Akademia Techniczna (WAT) [Wojskowa Akademia Techniczna]
Małgorzata Norek,,
, Thomas Kollin Nielsen - Aarhus University (AU) [Aarhus Universitet]
Thomas Kollin Nielsen,,
, Marek Polanski - Wojskowa Akademia Techniczna (WAT) [Wojskowa Akademia Techniczna]
Marek Polanski,,
, Izabela Kunce - Wojskowa Akademia Techniczna im. Jarosława Dąbrowskiego (WAT) [Wojskowa Akademia Techniczna]
Izabela Kunce,,
, Tomasz Płociński (FMSE / DMD)
Tomasz Płociński,,
- Division of Materials Design
, Leszek R. Jaroszewicz - Wojskowa Akademia Techniczna (WAT) [Wojskowa Akademia Techniczna]
Leszek R. Jaroszewicz,,
, Y. Cerenius - [Lunds Universitet]
Y. Cerenius,,
, Torben René Jensen - Aarhus University (AU) [Aarhus Universitet]
Torben René Jensen,,
, Jerzy Bystrzycki - Wojskowa Akademia Techniczna (WAT) [Wojskowa Akademia Techniczna]
Jerzy Bystrzycki,,
Journal seriesInternational Journal of Hydrogen Energy, ISSN 0360-3199, (A 35 pkt)
Issue year2011
Pages10760 - 10770
Publication size in sheets0.5
Keywords in EnglishIn situ SR-PXD; Magnesium-cobalt hydride; Mechanical milling; Microstructure; Synthesis
ASJC Classification2102 Energy Engineering and Power Technology; 3104 Condensed Matter Physics; 2103 Fuel Technology; 2105 Renewable Energy, Sustainability and the Environment
Languageen angielski
Synthesis-and-decomposition-mechanisms-of-ternary-Mg_2011_International-Jour.pdf 2.59 MB
Score (nominal)35
Score sourcejournalList
Publication indicators WoS Citations = 20; Scopus Citations = 22; Scopus SNIP (Source Normalised Impact per Paper): 2011 = 1.829; WoS Impact Factor: 2011 = 4.054 (2) - 2011=4.402 (5)
Citation count*25 (2020-01-31)
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