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

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• 作者：M. Porcu ; A.K. Petford-Long ; J.M. Sykes
• 关键词：Hydrogen storage ; Magnesium hydride ; Niobium oxide ; Transmission electron microscopy
• 刊名：Journal of Alloys and Compounds
• 出版年：2008
• 期刊代码：45_09258388
• 类别：ms
• 出版时间：3 April 2008
• 卷：453
• 期：1-2
• 页码：341-346
• 文件大小：1051 K

摘要

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.