NbF 5 additive improves hydrogen release from magnesium borohydride

Ahmad Al-Kukhun; Hyun Tae Hwang; Arvind Varma

doi:10.1016/j.ijhydene.2012.09.097

NbF ₅ additive improves hydrogen release from magnesium borohydride

Ahmad Al-Kukhun, Hyun Tae Hwang, Arvind Varma

Chemical and Materials Engineering

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

49 Scopus citations

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
Pages (from-to)	17671-17677
Number of pages	7
Journal	International Journal of Hydrogen Energy
Volume	37
Issue number	23
DOIs	https://doi.org/10.1016/j.ijhydene.2012.09.097
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

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

Access to Document

10.1016/j.ijhydene.2012.09.097

Cite this

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title = "NbF 5 additive improves hydrogen release from magnesium borohydride",

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.",

keywords = "Dehydrogenation, Hydrogen storage, Magnesium borohydride, Metal complex hydrides, Niobium fluoride",

author = "Ahmad Al-Kukhun and Hwang, {Hyun Tae} and Arvind Varma",

year = "2012",

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T1 - NbF 5 additive improves hydrogen release from magnesium borohydride

AU - Al-Kukhun, Ahmad

AU - Hwang, Hyun Tae

AU - Varma, Arvind

PY - 2012/12

Y1 - 2012/12

N2 - 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.

AB - 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.

KW - Dehydrogenation

KW - Hydrogen storage

KW - Magnesium borohydride

KW - Metal complex hydrides

KW - Niobium fluoride

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