Mao, J., Gu, Q. and Gregory, D. H. (2015) Revisiting the hydrogen storage behavior of the Na-O-H system. Materials, 8(5), pp. 2191-2203. (doi: 10.3390/ma8052191) (PMCID:PMC5455565)
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Abstract
Solid-state reactions between sodium hydride and sodium hydroxide are unusual among hydride-hydroxide systems since hydrogen can be stored reversibly. In order to understand the relationship between hydrogen uptake/release properties and phase/structure evolution, the dehydrogenation and hydrogenation behavior of the Na-O-H system has been investigated in detail both ex- and in-situ. Simultaneous thermogravimetric-differential thermal analysis coupled to mass spectrometry (TG-DTA-MS) experiments of NaH-NaOH composites reveal two principal features: Firstly, an H2 desorption event occurring between 240 and 380 °C and secondly an additional endothermic process at around 170 °C with no associated weight change. In-situ high-resolution synchrotron powder X-ray diffraction showed that NaOH appears to form a solid solution with NaH yielding a new cubic complex hydride phase below 200 °C. The Na-H-OH phase persists up to the maximum temperature of the in-situ diffraction experiment shortly before dehydrogenation occurs. The present work suggests that not only is the inter-phase synergic interaction of protic hydrogen (in NaOH) and hydridic hydrogen (in NaH) important in the dehydrogenation mechanism, but that also an intra-phase Hδ+… Hδ– interaction may be a crucial step in the desorption process.
| Item Type: | Articles |
|---|---|
| Additional Information: | The research post for JM has received funding from the European Union's Seventh Framework 610 Programme (FP7/2007-2013) for the Fuel Cells and Hydrogen Joint Technology Initiative under Grant 611 Agreement number 303447. |
| Keywords: | Hydrogen storage, sodium oxide, sodium hydride, sodium hydroxide, in-situ synchrotron powder diffraction. |
| Status: | Published |
| Refereed: | Yes |
| Glasgow Author(s) Enlighten ID: | Mao, Dr Jianfeng and Gregory, Professor Duncan |
| Authors: | Mao, J., Gu, Q., and Gregory, D. H. |
| College/School: | College of Science and Engineering > School of Chemistry |
| Journal Name: | Materials |
| Publisher: | MDPI |
| ISSN: | 1996-1944 |
| ISSN (Online): | 1996-1944 |
| Published Online: | 28 April 2015 |
| Copyright Holders: | Copyright © 2017 The Authors |
| First Published: | First published in Materials 8(5): 2191-2203 |
| Publisher Policy: | Reproduced under a Creative Commons license |
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