Investigation on synthesis, structure and catalytic modification of Ca(AlH4)2 complex hydride

Li, Changxu; Xiao, Xuezhang; Ge, Peiqian; Xue, Jingwen; Li, Shouquan; Ge, Hongwei; Chen, Lixin

doi:10.1016/j.ijhydene.2011.03.151

Cited by 12 publications

(13 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Recently, considerable efforts have further been carried out to develop alkaline-earth metal alanates as potentially promising hydrogen storage materials [11][12][13][14][15][16][17][18][19][20][21]. For example, Mg(AlH 4 ) 2 (∼9.3 wt.% H) and Ca(AlH 4 ) 2 (∼7.9 wt.% H) can be synthesized not only by wet-chemical or mechano-chemical metathesis reaction of alkali metal alanates with alkaline-earth metal chlorides [11][12][13][14][15] but also by direct ball-milling of AlH 3 with MgH 2 or CaH 2 hydrides [16].…”

Section: Introductionmentioning

confidence: 99%

“…For example, Mg(AlH 4 ) 2 (∼9.3 wt.% H) and Ca(AlH 4 ) 2 (∼7.9 wt.% H) can be synthesized not only by wet-chemical or mechano-chemical metathesis reaction of alkali metal alanates with alkaline-earth metal chlorides [11][12][13][14][15] but also by direct ball-milling of AlH 3 with MgH 2 or CaH 2 hydrides [16]. It was found that Mg(AlH 4 ) 2 and Ca(AlH 4 ) 2 might decompose and release hydrogen in two and four steps, respectively [12,[14][15][16], and their dehydrogenation temperature could be reduced by adding catalysts [15,[19][20][21]. Element substitution has been becoming an effective approach to adjust the de-/hydrogenation thermodynamics of conventional metal hydrides and novel complex hydrides [22][23][24][25].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Synthesis, crystal structure and thermal decomposition of LiCa(AlH4)3

Liu

Qian

et al. 2012

Journal of Alloys and Compounds

View full text Add to dashboard Cite

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Synthesis, crystal structure and thermal decomposition of LiCa(AlH4)3

Liu

Qian

et al. 2012

Journal of Alloys and Compounds

View full text Add to dashboard Cite

“…The theoretical capacity of reaction (1) is 4.32 wt % H 2 and, accordingly, less taking into account of the practical purity of the reactants. It must be pointed out that reaction (1) was also reported to occur during mechano-chemical activation synthesis (MCAS) of Ca(AlH 4 ) 2 using such reactants as sodium alanate (NaAlH 4 ) and calcium chloride (CaCl 2 ) [ 13 , 14 , 15 , 16 , 17 ]. So far, the only attempt to use LiAlH 4 as a reactant with CaCl 2 to synthesize Ca(AlH 4 ) 2 by MCAS was reported in [ 13 ] but without any details.…”

Section: Resultsmentioning

confidence: 99%

“…After 2.5 and 5 h of ball milling no diffraction peaks of Ca(AlH 4 ) 2 are visible anymore ( Figure 3 b). It must be pointed out that reaction (2) also occurs during thermal decomposition of Ca(AlH 4 ) 2 [ 13 , 14 , 15 , 16 , 17 ]. Table 1 summarizes the phases present in the microstructure after various milling durations as established from the XRD analysis.…”

Section: Resultsmentioning

confidence: 99%

Mechanical and Thermal Dehydrogenation of the Mechano-Chemically Synthesized Calcium Alanate (Ca(AlH4)2) and Lithium Chloride (LiCl) Composite

2015

View full text Add to dashboard Cite

LiAlH4 and CaCl2 were employed for mechano-chemical activation synthesis (MCAS) of Ca(AlH4)2 and LiCl hydride composite. After short ball milling time, their X-ray diffraction (XRD) peaks are clearly observed. After ball milling for a longer duration than 0.5 h, the CaAlH5 diffraction peaks are observed which indicates that Ca(AlH4)2 starts decomposing during ball milling into CaAlH5+Al+1.5H2. It is estimated that less than 1 wt % H2 was mechanically dehydrogenated in association with decomposition reaction. After 2.5 h of ball milling, no Ca(AlH4)2 diffraction peaks were observed on XRD patterns which suggests that Ca(AlH4)2 was decomposed. Thermal behavior of ball milled powders, which was investigated by thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC), indicates that a certain fraction of Ca(AlH4)2 could have been disordered/amorphized during ball milling being undetectable by XRD. The apparent activation energy for the decomposition of Ca(AlH4)2 and CaAlH5 equals 135 kJ/mol and 183 kJ/mol, respectively.

show abstract

“…обнаружили появление на графиках этих процессов экзо-, эндопики, изгибы или изломы в точках фазовых превращений [1, [25][26][27][28][29][30][31][32].…”

Section: Introductionunclassified

Thermal Gradual Dehydrogenation of Calcium Alanate Ca(AlH$_{4}$)$_{2}$. The System Phase Composition During the Process of Dehydrogenation

Zaginaichenko¹,

Schur²,

Матысина³

et al. 2016

Metallofiz. Noveishie Tekhnol.

View full text Add to dashboard Cite

Разработана статистическая теория термического поэтапного распада аланата кальция с выделением водорода. Рассчитаны свободные энергии всех составляющих фаз химических реакций в зависимости от темпера-туры, концентрации атомов водорода, их активности и значений энерге-тических параметров системы. Получены условия термодинамического равновесия всех фаз, определяющие температурную зависимость концен-трации водорода. С использованием литературных экспериментальных данных оценены численные значения энергетических констант. Построе-ны графики температурной зависимости растворимости водорода в фазах, на которых проявляются изломы или изгибы в точках фазовых перехо-дов. Получен график температурной зависимости выделения водорода в системе с ростом температуры. Проведено сравнение численных значений свободных энергий фаз в точках фазовых превращений, подтверждающее экспериментально проявляющийся фазовый состав системы, т.е. воз-можность реализации каждой фазы в определённых температурных и концентрационных по водороду интервалах.Розроблено статистичну теорію термічного поетапного розпаду аланату кальцію з виділенням водню. Розраховано вільні енергії усіх складових фаз хімічних реакцій залежно від температури, концентрації атомів вод-ню, їх активності і значень енергетичних параметрів системи. Одержано умови термодинамічної рівноваги всіх фаз, що визначають температурну залежність концентрації водню. З використанням літературних експери-ментальних даних оцінено чисельні значення енергетичних констант. Побудовано графіки температурної залежності розчинності водню у фа-зах, на яких проявляються злами або вигини в точках фазових переходів.

show abstract

Investigation on synthesis, structure and catalytic modification of Ca(AlH4)2 complex hydride

Cited by 12 publications

References 28 publications

Synthesis, crystal structure and thermal decomposition of LiCa(AlH4)3

Synthesis, crystal structure and thermal decomposition of LiCa(AlH4)3

Mechanical and Thermal Dehydrogenation of the Mechano-Chemically Synthesized Calcium Alanate (Ca(AlH4)2) and Lithium Chloride (LiCl) Composite

Thermal Gradual Dehydrogenation of Calcium Alanate Ca(AlH$_{4}$)$_{2}$. The System Phase Composition During the Process of Dehydrogenation

Contact Info

Product

Resources

About