Revisiting the Hydrogen Storage Behavior of the Na-O-H System
| Autor: | Jianfeng Mao, Qinfen Gu, Duncan H. Gregory |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2015 |
| Předmět: |
hydrogen storage
sodium oxide sodium hydride sodium hydroxide in-situ synchrotron powder diffraction Technology Electrical engineering. Electronics. Nuclear engineering TK1-9971 Engineering (General). Civil engineering (General) TA1-2040 Microscopy QH201-278.5 Descriptive and experimental mechanics QC120-168.85 |
| Zdroj: | Materials, Vol 8, Iss 5, Pp 2191-2203 (2015) |
| Druh dokumentu: | article |
| ISSN: | 1996-1944 |
| DOI: | 10.3390/ma8052191 |
| Popis: | 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. |
| Databáze: | Directory of Open Access Journals |
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