Decomposition and formation of magnesium borohydride

Saldan, Ivan

doi:10.1016/j.ijhydene.2016.05.062

Cited by 30 publications

(26 citation statements)

References 142 publications

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“…Obtained results are in good agreement with those previously reported in [6][13][32] [8]. Small temperature differences between the results obtained in this work and literature results can be due to different applied conditions of pressure and heating rate during the measurement [32].…”

Section: (Figure 2)supporting

confidence: 91%

“…According to Soloveichik et al [6] , Li et al [11] and Saldan [8], the first two endothermic peaks (162 and 194ºC) are related to the phase transformation of MBH. Then, in the range of 300-450ºC, MBH was decomposed in 3 different steps (D1-D3).…”

Section: (Figure 2)mentioning

confidence: 97%

“…Different strategies have been tested in order to improve not only the reversibility but also the kinetics and the temperature of the desorption reactions [16] and recently reviewed in [8]. The addition of different additives or catalysts such as NbF 5 , TiO 2 , CoCl 2 , CoF 2 or TiCl 3 among others [14][15], the confinement in porous materials (mainly in carbon materials) [19][20][21], their combinations [23] or the formation of composites [24] are some of the proposals that have been studied.…”

Section: Introductionmentioning

confidence: 99%

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Reversible hydrogen sorption in the composite made of magnesium borohydride and silica aerogel

Rueda

Sanz-Moral

Girella³

et al. 2016

International Journal of Hydrogen Energy

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Magnesium borohydride Mg(BH 4 ) 2 is a promising hydrogen storage material as it releases high hydrogen storage capacity at mild desorption temperatures, but it is still limited by slow hydrogen release kinetics and by the harsh conditions required to re-hydrogenate this compound. In this work, composites made of commercial Mg(BH 4 ) 2 and synthesized silica aerogel microparticles were prepared by thermal treatment in hydrogen under 120 bar and 200ºC. As a result, the sorption properties of the hydride are improved: calorimetric measurements show that decomposition temperature is reduced by 60ºC, and the typical 3-step decomposition mechanism of Mg(BH 4 ) 2 changes to a single-step mechanism in range of 220-400°C. The kinetics of the first dehydrogenation at 300ºC was two times faster in Mg(BH 4 ) 2 -SiO 2 composites than in the case of bulk γ-Mg(BH 4 ) 2 . Additionally, the re-hydrogenation of this material at comparatively moderate conditions of 390ºC and 110 bar is presented for the first time, achieving cyclability with a reversible release of hydrogen up to 6wt%. Different amounts of hydrogen were exchanged depending on the temperature of desorption (300ºC or 400ºC) and the presence or absence of silica aerogel. This result indicates that silica aerogel chemically interacts with Mg(BH 4 ) 2 , acting as an additive, which can result in different hydrogenationdehydrogenation routes in which different amounts and types of intermediates are formed, influencing the kinetics and the cyclability.

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Section: (Figure 2)supporting

confidence: 91%

Section: (Figure 2)mentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

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Reversible hydrogen sorption in the composite made of magnesium borohydride and silica aerogel

Rueda

Sanz-Moral

Girella³

et al. 2016

International Journal of Hydrogen Energy

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“…[ 12–14 ] The high kinetic energy barriers resulting from the sluggish diffusion of hydrogen and mass transport, however, cause the operating storage temperature to rise over 300 °C. [ 15–18 ] Moreover, the reversibility of Mg(BH 4 ) 2 that could be achieved was only partial, even under an extreme condition of 950 bar H 2 at 400 °C, which is impractical for many applications, and this poses a major barrier for the future application of Mg(BH 4 ) 2 as hydrogen storage materials. [ 19,20 ]…”

Section: Figurementioning

confidence: 99%

Heterostructures Built in Metal Hydrides for Advanced Hydrogen Storage Reversibility

et al. 2020

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Hydrogen storage is a vital technology for developing on‐board hydrogen fuel cells. While Mg(BH4)2 is widely regarded as a promising hydrogen storage material owing to its extremely high gravimetric and volumetric capacity, its poor reversibility poses a major bottleneck inhibiting its practical applications. Herein, a facile strategy to effectively improve the reversible hydrogen storage performance of Mg(BH4)2 via building heterostructures uniformly inside MgH2 nanoparticles is reported. The in situ reaction between MgH2 nanoparticles and B2H6 not only forms homogeneous heterostructures with controllable particle size but also simultaneously decreases the particle size of the MgH2 nanoparticles inside, which effectively reduces the kinetic barrier that inhibits the reversible hydrogen storage in both Mg(BH4)2 and MgH2. More importantly, density functional theory coupled with ab initio molecular dynamics calculations clearly demonstrates that MgH2 in this heterostructure can act as a hydrogen pump, which drastically changes the enthalpy for the initial formation of BH bonds by breaking stable BB bonds from endothermic to exothermic and hence thermodynamically improves the reversibility of Mg(BH4)2. It is believed that building heterostructures provides a window of opportunity for discovering high‐performance hydrogen storage materials for on‐board applications.

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“…The safe storage of hydrogen in a compact and efficient form remains a formidable challenge towards the realization of energy decarbonization. Among the wide range of complex hydride materials studied, Mg(BH 4 ) 2 has garnered tremendous interest from the storage community because of desirable physical and thermodynamic properties [1][2][3][4]. Mg(BH 4 ) 2 features a high gravimetric density of H 2 (ca.…”

Section: Introductionmentioning

confidence: 99%

Effects of Glymes on the Distribution of Mg(B10H10) and Mg(B12H12) from the Thermolysis of Mg(BH4)2

et al. 2021

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We examined the effects of concentrations and identities of various glymes, from monoglyme up to tetraglyme, on H2 release from the thermolysis of Mg(BH4)2 at 160–200 °C for 8 h. 11B NMR analysis shows major products of Mg(B10H10) and Mg(B12H12); however, their relative ratio is highly dependent both on the identity and concentration of the glyme to Mg(BH4)2. Selective formation of Mg(B10H10) was observed with an equivalent of monoglyme and 0.25 equivalent of tetraglyme. However, thermolysis of Mg(BH4)2 in the presence of stoichiometric or greater equivalent of glymes can lead to unselective formation of Mg(B10H10) and Mg(B12H12) products or inhibition of H2 release.

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Decomposition and formation of magnesium borohydride

Cited by 30 publications

References 142 publications

Reversible hydrogen sorption in the composite made of magnesium borohydride and silica aerogel

Reversible hydrogen sorption in the composite made of magnesium borohydride and silica aerogel

Heterostructures Built in Metal Hydrides for Advanced Hydrogen Storage Reversibility

Effects of Glymes on the Distribution of Mg(B10H10) and Mg(B12H12) from the Thermolysis of Mg(BH4)2

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