Metal‐Borohydride‐Modified Zr(BH4)4⋅8 NH3: Low‐Temperature Dehydrogenation Yielding Highly Pure Hydrogen

Huang, Jin‐Shun; Ouyang, Liuzhang; Gu, Qinfen; Yu, Xuebin; Zhu, Min

doi:10.1002/chem.201501461

Cited by 13 publications

(6 citation statements)

References 34 publications

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“…The peak at ~43 ° is assigned to the stainless steel sample holder. A typical FTIR spectrum of NaBH4 would display vibrational peaks associated with the BH4group in the region of 2410-2200 cm -1 corresponding to the stretching mode of BH4 -, whereas the bending modes of BH4 -are to be found around 1120 cm -1 [19,20].…”

Section: Composition Of the As-synthesized Materialsmentioning

confidence: 99%

Direct Synthesis of NaBH4 Nanoparticles from NaOCH3 for Hydrogen Storage

Wang

Aguey‐Zinsou

2019

Energies

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Hydrogen is regarded as a promising energy carrier to substitute fossil fuels. However, storing hydrogen with high density remains a challenge. NaBH 4 is a potential hydrogen storage material due to its high gravimetric hydrogen density (10.8 mass%), but the hydrogen kinetic and thermodynamic properties of NaBH 4 are poor against the application needs. Nanosizing is an effective strategy to improve the hydrogen properties of NaBH 4 . In this context, we report on the direct synthesis of NaBH 4 nanoparticles (~6-260 nm) from the NaOCH 3 precursor. The hydrogen desorption properties of such nanoparticles are reported as well as experimental conditions that lead to the synthesis of (Na 2 B 12 H 12 ) free NaBH 4 nanoparticles.

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Section: Composition Of the As-synthesized Materialsmentioning

confidence: 99%

Direct Synthesis of NaBH4 Nanoparticles from NaOCH3 for Hydrogen Storage

Wang

Aguey‐Zinsou

2019

Energies

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“…The use of NH 3 ligands to saturate and immobilize the metal cation with formation of ammine metal borohydrides (AMBs, [M(NH 3 ) x ][BH 4 ] y ) is an effective strategy to improve thermodynamic stability of metal borohydrides. − Although AMBs show improvement of dehydrogenation properties and prevention of B 2 H 6 release compared to metal borohydrides, many of these AMBs tend to release ammonia during thermal decomposition. It has been reported that [Li(NH 3 ) x ][BH 4 ] and [Ca(NH 3 ) x ][BH 4 ] 2 ( x = 1, 2, and 4) release a significant amount of ammonia below 300 °C under dynamic situation. ,, The [Mg(NH 3 ) 2 ][BH 4 ] 2 and [Al(NH 3 ) 6 ][BH 4 ] 3 mainly release hydrogen with a certain amount of ammonia detected during decomposition. , Among these AMBs, zinc ammine borohydride, [Zn(NH 3 ) 2 ][BH 4 ] 2 , shows favorable dehydrogenation properties in terms of hydrogen desorption temperature and purity of gas release.…”

Section: Introductionmentioning

confidence: 99%

Decomposition Mechanism of Zinc Ammine Borohydride: A First-Principles Calculation

Chen

Zou

et al. 2018

J. Phys. Chem. C

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The decomposition mechanism of zinc ammine borohydride ([Zn(NH 3) 2 ][BH 4 ] 2) has been studied by density functional theory calculation. The release of B 2 H 6 and BH 3 is predicted to be kinetically and/or thermodynamically unfavorable for [Zn(NH 3) 2 ][BH 4 ] 2 , in agreement with experimental results that no boranes were detected during decomposition. The climbing image nudged elastic band calculation and ab initio molecular dynamics simulations indicate the formation of NH 3 BH 3 and B 2 H 7-intermediates during decomposition of [Zn(NH 3) 2 ][BH 4 ] 2 , which is different from that observed for other reported ammine metal borohydrides. The dehydrogenation occurs through reaction pathways involving transfer of hydrides from the Zn cation to BH 4-or transfer of protons from NH 3 BH 3 to NH 3 .

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“…13 Furthermore, recent experiments have mixed various MBAs with MBs or ammonia borane (NH 3 BH 3 ) to tune the H 2 release temperature and purity. 19,20 Looking at the available experimental data for a large number of MBAs, a clear pattern emerges between the Pauling electronegativity χ p of the metal M in M (BH 4 ) x and the material's decomposition temperature. 21 As can be seen in Fig.…”

Section: Introductionmentioning

confidence: 99%

Decomposition mechanisms in metal borohydrides and their ammoniates

Welchman

Thonhauser

2017

J. Mater. Chem. A

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Ammoniation in metal borohydrides (MBs) with the form M (BH 4 ) x has been shown to lower their decomposition temperatures with M of low electronegativity (χ p 1.6), but raise it for high-χ p MBs (χ p 1.6). Although this behavior is just as desired, an understanding of the mechanisms that cause it is still lacking. Using ab initio methods, we elucidate those mechanisms and find that ammoniation always causes thermodynamic destabilization, explaining the observed lower decomposition temperatures for low-χ p MBs. For high-χ p MBs, we find that ammoniation blocks B 2 H 6 formation-the preferred decomposition mechanism in these MBs-and thus kinetically stabilizes those phases. The shift in decomposition pathway that causes the distinct change from destabilization to stabilization around χ p = 1.6 thus coincides with the onset of B 2 H 6 formation in MBs. Furthermore, with our analysis we are also able to explain why these materials release either H 2 or NH 3 gas upon decomposition. We find that NH 3 is much more strongly coordinated with higher-χ p metals and direct H 2 formation/release becomes more favorable in these materials. Our findings are of importance for unraveling the hydrogen release mechanisms in an important new and promising class of hydrogen storage materials, allowing for a guided tuning of their chemistry to further improve their properties.

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Metal‐Borohydride‐Modified Zr(BH₄)₄⋅8 NH₃: Low‐Temperature Dehydrogenation Yielding Highly Pure Hydrogen

Cited by 13 publications

References 34 publications

Direct Synthesis of NaBH4 Nanoparticles from NaOCH3 for Hydrogen Storage

Direct Synthesis of NaBH4 Nanoparticles from NaOCH3 for Hydrogen Storage

Decomposition Mechanism of Zinc Ammine Borohydride: A First-Principles Calculation

Decomposition mechanisms in metal borohydrides and their ammoniates

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