Abstract
The dehydrogenation properties of Mg(BH 4) 2 with various additives (SiO 2, VCl 3, CoCl 2 and NbF 5) were investigated. The addition of NbF 5 significantly improved the extent of hydrogen release as well as the kinetics. While neat Mg(BH 4) 2 starts to release hydrogen >270 °C, Mg(BH 4) 2 with NbF 5 begins hydrogen release ∼75 °C, as confirmed by mass spectrometry and thermogravimetry. The maximum hydrogen yield of Mg(BH 4) 2, obtained in the presence of 15 wt% NbF 5, was 3.7, 7.4, 10.0, 11.4 wt% for 150, 250, 300 and 350 °C, respectively. Using pXRD, we confirmed that the final crystalline product at 300 °C from Mg(BH 4) 2 + 15 wt% NbF 5 was Mg, while it was MgH 2 for neat Mg(BH 4) 2. Solid state 11B NMR analysis of Mg(BH 4) 2 with 15 wt% NbF 5 at 300 °C showed significant selectivity toward the formation of Mg(B 12H 12) as intermediate, while neat Mg(BH 4) 2 showed β-Mg(BH 4) 2, Mg(B 2H 6) as well as some Mg(B 12H 12). Our results demonstrate that NbF 5 is a promising additive to provide high hydrogen yield values from Mg(BH 4) 2 at moderate temperatures <300 °C.
Original language | English |
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Pages (from-to) | 17671-17677 |
Number of pages | 7 |
Journal | International Journal of Hydrogen Energy |
Volume | 37 |
Issue number | 23 |
DOIs | |
State | Published - Dec 2012 |
Keywords
- Dehydrogenation
- Hydrogen storage
- Magnesium borohydride
- Metal complex hydrides
- Niobium fluoride
ASJC Scopus subject areas
- Renewable Energy, Sustainability and the Environment
- Fuel Technology
- Condensed Matter Physics
- Energy Engineering and Power Technology