Effect of Mechanical Activation on the Reaction of Magnesium Hydride with Water

Lukashev, R. V.; Yakovleva, N. A.; Klyamkin, S. N.; Тарасов, Б. П.

doi:10.1134/s0036023608030017

Cited by 32 publications

(13 citation statements)

References 10 publications

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“…Several hydrolysis studies of MgH 2 have been conducted using ball-milled MgH 2 powder supplemented with graphite [9] or rareearth metal [10]. The compounds generate hydrogen in pure water at room temperature.…”

Section: Introductionmentioning

confidence: 99%

Industrial production of MgH2 and its application

Uesugi¹,

Sugiyama²,

Nii³

et al. 2011

Journal of Alloys and Compounds

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Section: Introductionmentioning

confidence: 99%

Industrial production of MgH2 and its application

Uesugi¹,

Sugiyama²,

Nii³

et al. 2011

Journal of Alloys and Compounds

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“…The need for compact, safe, and inexpensive hydrogen sources is a key issue for the development of fuel cells. One of the most attractive metal hydrides for hydrogen generation is magnesium hydride, (MgH 2 ) [7][8][9][10][11][12][13][14][15][16][17]. It is an especially promising material owing to its quite high hydrogen capacity of 7.6 mass% and relatively low production cost.…”

Section: Introductionmentioning

confidence: 99%

“…Several studies have used metallic powders with high chemical activity via a ball-milling method [7,[9][10][11][12][13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Chemical equilibrium analysis for hydrolysis of magnesium hydride to generate hydrogen

Hiraki

Hiroi

Akashi

et al. 2012

International Journal of Hydrogen Energy

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Magnesium hydride is a promising hydrogen source because of its high mass density of hydrogen, 15.2%, when it is hydrolyzed; MgH 2 + 2H 2 O = Mg(OH) 2 + 2H 2 + 277 kJ. However, a magnesium hydroxide, Mg(OH) 2 , layer forms rapidly on the surface of the unreacted MgH 2 as the pH increases, hindering further reaction. The purpose of this study is to find acids that could effectively accelerate the reaction by using a chemical equilibrium analysis where the relationships of pH to concentration of ionized Mg were calculated. For the best performing acid, the calculated and measured relationships were compared, and the effects of acid concentration on hydrogen release were measured. The analysis revealed that citric acid and ethylenediamine-tetraacetic acid were good buffering agents. The calculated and measured relationships between pH and concentration of ionized Mg were in good accord. Hydrogen release improved considerably in a relatively dilute citric acid solution instead of pure distilled water. The maximum amount of hydrogen generated was 1.7  10 3 cm 3 ·g -1 at STP after 30 min. We estimated the exact concentration of citric acid solution for complete MgH 2 hydrolysis by a chemical equilibrium analysis method.

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“…Due to the hydrogen generation by hydrolysis having the excellent properties of widely raw material sources, high hydrogen generation yield, high hydrogen purity, and environmental friendliness, a large amount of metal hydrides have been studied as the mobile hydrogen source of fuel cell, such as LiH [43], CaH2 [44], MgH2 [45][46][47][48], NaBH4 [49][50][51], LiBH4 [52,53], LiAlH4 [42,52]. Among them, LiH, CaH2, and LiAlH4 can react with water violently, so the uncontrollable reaction leads to poor practicability.…”

mentioning

confidence: 99%

Enhanced Hydrogen Generation Properties of MgH2-Based Hydrides by Breaking the Magnesium Hydroxide Passivation Layer

Ouyang

Huang

et al. 2015

Energies

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Due to its relatively low cost, high hydrogen yield, and environmentally friendly hydrolysis byproducts, magnesium hydride (MgH2) appears to be an attractive candidate for hydrogen generation. However, the hydrolysis reaction of MgH2 is rapidly inhibited by the formation of a magnesium hydroxide passivation layer. To improve the hydrolysis properties of MgH2-based hydrides we investigated three different approaches: ball milling, synthesis of MgH2-based composites, and tuning of the solution composition. We demonstrate that the formation of a composite system, such as the MgH2/LaH3 composite, through ball milling and in situ synthesis, can improve the hydrolysis properties of MgH2 in pure water. Furthermore, the addition of Ni to the MgH2/LaH3 composite resulted in the synthesis of LaH3/MgH2/Ni composites. The LaH3/MgH2/Ni composites exhibited a higher hydrolysis rate-120 mL/(g·min) of H2 in the first 5 min-than the MgH2/LaH3 composite-95 mL/(g·min)-without the formation of the magnesium hydroxide passivation layer. Moreover, the yield rate was controlled by manipulation of the particle size via ball milling. OPEN ACCESSEnergies 2015, 8 4238The hydrolysis of MgH2 was also improved by optimizing the solution. The MgH2 produced 1711.2 mL/g of H2 in 10 min at 298 K in the 27.1% ammonium chloride solution, and the hydrolytic conversion rate reached the value of 99.5%.

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Effect of Mechanical Activation on the Reaction of Magnesium Hydride with Water

Cited by 32 publications

References 10 publications

Industrial production of MgH2 and its application

Industrial production of MgH2 and its application

Chemical equilibrium analysis for hydrolysis of magnesium hydride to generate hydrogen

Enhanced Hydrogen Generation Properties of MgH2-Based Hydrides by Breaking the Magnesium Hydroxide Passivation Layer

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