TEM studies of Nb2O5 catalyst in ball-milled MgH2 for hydrogen storage

M. Porcu; A. K. Petford-Long; J. M. Sykes

doi:10.1016/j.jallcom.2006.11.147

TEM studies of Nb₂O₅ catalyst in ball-milled MgH₂ for hydrogen storage

M. Porcu^*, A. K. Petford-Long, J. M. Sykes

^*Corresponding author for this work

Materials Science and Engineering

Research output: Contribution to journal › Article › peer-review

91 Scopus citations

Abstract

In this paper we report microstructural studies by transmission electron microscopy (TEM) of magnesium hydride nanocomposites produced by ball milling. The work employed high angle annular dark field (HAADF) imaging, high resolution TEM (HRTEM), and electron energy loss spectroscopy (EELS). MgH₂ samples had been prepared by ball-milling with 17 wt% of Nb₂O₅. Samples milled for a short time (30 h) show a decrease in particle size in comparison to MgH₂ milled alone for the same amount of time. After only 30 h milling, finely dispersed Nb₂O₅ was detected within the MgH₂ matrix. After milling for longer times (300 h) the amount of Nb₂O₅ dispersed within the Mg matrix increases. Analysis of material that had been milled for 300 h and then subjected to hydrogen desorption by heating showed that MgH₂ and Nb₂O₅ interact during the thermal desorption forming both a partially reduced niobium oxide phase and a mixed Nb-Mg-O phase.

Original language	English (US)
Pages (from-to)	341-346
Number of pages	6
Journal	Journal of Alloys and Compounds
Volume	453
Issue number	1-2
DOIs	https://doi.org/10.1016/j.jallcom.2006.11.147
State	Published - Apr 3 2008

Keywords

Hydrogen storage
Magnesium hydride
Niobium oxide
Transmission electron microscopy

ASJC Scopus subject areas

Mechanics of Materials
Mechanical Engineering
Metals and Alloys
Materials Chemistry

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10.1016/j.jallcom.2006.11.147

Cite this

@article{a921842b3d9e4744aaf41ff6e3e4443b,

title = "TEM studies of Nb2O5 catalyst in ball-milled MgH2 for hydrogen storage",

abstract = "In this paper we report microstructural studies by transmission electron microscopy (TEM) of magnesium hydride nanocomposites produced by ball milling. The work employed high angle annular dark field (HAADF) imaging, high resolution TEM (HRTEM), and electron energy loss spectroscopy (EELS). MgH2 samples had been prepared by ball-milling with 17 wt% of Nb2O5. Samples milled for a short time (30 h) show a decrease in particle size in comparison to MgH2 milled alone for the same amount of time. After only 30 h milling, finely dispersed Nb2O5 was detected within the MgH2 matrix. After milling for longer times (300 h) the amount of Nb2O5 dispersed within the Mg matrix increases. Analysis of material that had been milled for 300 h and then subjected to hydrogen desorption by heating showed that MgH2 and Nb2O5 interact during the thermal desorption forming both a partially reduced niobium oxide phase and a mixed Nb-Mg-O phase.",

keywords = "Hydrogen storage, Magnesium hydride, Niobium oxide, Transmission electron microscopy",

author = "M. Porcu and Petford-Long, {A. K.} and Sykes, {J. M.}",

note = "Funding Information: The work has been supported by the Research Training Network “H-Sorption in MgH 2 ” of the 5th Framework Programme of the EU Commission. Contract number: HPRN-CT-2002-00208. We are grateful to GKSS for provision of samples and technical advice and to Professor G.D.W. Smith for provision of laboratory facilities. M.P. wishes to thank the Electron Microscopy staff of the Department of Materials, Oxford University, for technical support.",

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AU - Porcu, M.

AU - Petford-Long, A. K.

AU - Sykes, J. M.

N1 - Funding Information: The work has been supported by the Research Training Network “H-Sorption in MgH 2 ” of the 5th Framework Programme of the EU Commission. Contract number: HPRN-CT-2002-00208. We are grateful to GKSS for provision of samples and technical advice and to Professor G.D.W. Smith for provision of laboratory facilities. M.P. wishes to thank the Electron Microscopy staff of the Department of Materials, Oxford University, for technical support.

PY - 2008/4/3

Y1 - 2008/4/3

N2 - In this paper we report microstructural studies by transmission electron microscopy (TEM) of magnesium hydride nanocomposites produced by ball milling. The work employed high angle annular dark field (HAADF) imaging, high resolution TEM (HRTEM), and electron energy loss spectroscopy (EELS). MgH2 samples had been prepared by ball-milling with 17 wt% of Nb2O5. Samples milled for a short time (30 h) show a decrease in particle size in comparison to MgH2 milled alone for the same amount of time. After only 30 h milling, finely dispersed Nb2O5 was detected within the MgH2 matrix. After milling for longer times (300 h) the amount of Nb2O5 dispersed within the Mg matrix increases. Analysis of material that had been milled for 300 h and then subjected to hydrogen desorption by heating showed that MgH2 and Nb2O5 interact during the thermal desorption forming both a partially reduced niobium oxide phase and a mixed Nb-Mg-O phase.

AB - In this paper we report microstructural studies by transmission electron microscopy (TEM) of magnesium hydride nanocomposites produced by ball milling. The work employed high angle annular dark field (HAADF) imaging, high resolution TEM (HRTEM), and electron energy loss spectroscopy (EELS). MgH2 samples had been prepared by ball-milling with 17 wt% of Nb2O5. Samples milled for a short time (30 h) show a decrease in particle size in comparison to MgH2 milled alone for the same amount of time. After only 30 h milling, finely dispersed Nb2O5 was detected within the MgH2 matrix. After milling for longer times (300 h) the amount of Nb2O5 dispersed within the Mg matrix increases. Analysis of material that had been milled for 300 h and then subjected to hydrogen desorption by heating showed that MgH2 and Nb2O5 interact during the thermal desorption forming both a partially reduced niobium oxide phase and a mixed Nb-Mg-O phase.

KW - Hydrogen storage

KW - Magnesium hydride

KW - Niobium oxide

KW - Transmission electron microscopy

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