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Synthesis and decomposition mechanisms of ternary Mg2COH5 studied using in situ synchrotron X-ray diffraction

Norek, M.; Nielsen, T. K.; Polanski, M.; Kunce, I.; Plocinski, T.; Jaroszewicz, L. R.; Cerenius, Yngve LU ; Jensen, T. R. and Bystrzycki, J. (2011) In International Journal of Hydrogen Energy 36(17). p.10760-10770
Abstract
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 degrees C. The ternary hydride forms in less than 2.5 h (including the milling time) with a yield of similar to 90% at similar to 300 degrees 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... (More)
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 degrees C. The ternary hydride forms in less than 2.5 h (including the milling time) with a yield of similar to 90% at similar to 300 degrees 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 similar to 5 nm. Mg2COH5 decomposes at approximately 300 degrees C to elemental Mg and Co. Additionally, at approximately 400 degrees 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 Mg2COH5. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved. (Less)
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author
organization
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Contribution to journal
publication status
published
subject
keywords
Magnesium-cobalt hydride, Synthesis, Mechanical milling, In situ, SR-PXD, Microstructure
in
International Journal of Hydrogen Energy
volume
36
issue
17
pages
10760 - 10770
publisher
Elsevier
external identifiers
  • wos:000295235200035
  • scopus:80051602061
ISSN
1879-3487
DOI
10.1016/j.ijhydene.2011.05.126
language
English
LU publication?
yes
id
b5fd1f4c-2652-4285-bb18-ff5b3b37f1be (old id 2208317)
date added to LUP
2011-11-25 14:10:42
date last changed
2017-11-05 04:08:42
@article{b5fd1f4c-2652-4285-bb18-ff5b3b37f1be,
  abstract     = {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 degrees C. The ternary hydride forms in less than 2.5 h (including the milling time) with a yield of similar to 90% at similar to 300 degrees 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 similar to 5 nm. Mg2COH5 decomposes at approximately 300 degrees C to elemental Mg and Co. Additionally, at approximately 400 degrees 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 Mg2COH5. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.},
  author       = {Norek, M. and Nielsen, T. K. and Polanski, M. and Kunce, I. and Plocinski, T. and Jaroszewicz, L. R. and Cerenius, Yngve and Jensen, T. R. and Bystrzycki, J.},
  issn         = {1879-3487},
  keyword      = {Magnesium-cobalt hydride,Synthesis,Mechanical milling,In situ,SR-PXD,Microstructure},
  language     = {eng},
  number       = {17},
  pages        = {10760--10770},
  publisher    = {Elsevier},
  series       = {International Journal of Hydrogen Energy},
  title        = {Synthesis and decomposition mechanisms of ternary Mg2COH5 studied using in situ synchrotron X-ray diffraction},
  url          = {http://dx.doi.org/10.1016/j.ijhydene.2011.05.126},
  volume       = {36},
  year         = {2011},
}