Preparation of alkali metal hydrides by mechanical alloying

Elansari, L.; Antoine, L.; Janot, Raphaël; Gachon, J.C.; Kuntz, J.J.; Guérard, D.

doi:10.1016/s0925-8388(01)01615-2

Cited by 14 publications

(15 citation statements)

References 6 publications

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“…The calculated lattice parameter "a", for KH, RbH and CsH are 5.70 ± 0.010, 6.01 ± 0.012 and 6.37 ± 0.015, respectively. These values are in good agreement with those reported by Elansari et al [34]. Fig.…”

Section: Resultssupporting

confidence: 93%

“…The KH was obtained commercially whereas the RbH and CsH were synthesized in the laboratory. The RbH and CsH were prepared using a mechanical alloying method similar to the one described in a previous publication [31] and by Elansari et al [34]. In this method, a 45 ml stainless steel vial was placed into an argon filled glove box and approximately 4e5 g of alkali metal was added to it along with ten stainless steel balls (10 mm in diameter).…”

Section: Methodsmentioning

confidence: 99%

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Potassium, rubidium and cesium hydrides as dehydrogenation catalysts for the lithium amide/magnesium hydride system

Durojaiye

Hayes

Goudy

2015

International Journal of Hydrogen Energy

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Lithium amideDesorption kinetics Potassium hydride Rubidium hydride Cesium hydride a b s t r a c t In this study, the effectiveness of several alkali metal hydrides (KH, RbH and CsH) for improving the hydrogen desorption properties of a 2LiNH 2 /MgH 2 mixture was studied.Results showed that the relative effectiveness of these additives in decreasing the hydrogen desorption temperature, lowering the activation energy and increasing desorption rates from the mixtures is in the order: RbH > KH > CsH > Un-catalyzed. Modeling studies showed that diffusion through a Li 2 Mg(NH) 2 product layer is the rate-controlling process. It is believed that the alkali elements: K, Rb and Cs partially replace the Li in the product layer. This may have an inductive effect in which the NeH bond is weakened thus leading to lower desorption enthalpies. The lattice expansion caused by substitution of the larger alkali elements for Li may also allow for faster diffusion and increased desorption rates.

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Section: Resultssupporting

confidence: 93%

Section: Methodsmentioning

confidence: 99%

Potassium, rubidium and cesium hydrides as dehydrogenation catalysts for the lithium amide/magnesium hydride system

Durojaiye

Hayes

Goudy

2015

International Journal of Hydrogen Energy

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“…The hydrogenation of Rb to RbH under mechanochemical conditions was performed at low revolutions per minute (250 rpm). Otherwise, the metal is smeared over the wall of the milling vial and no complete hydrogenation can be observed [19]. In the next step, the mechanochemically induced hydrogenation of the RbH-Al mixture can be done with 450 rpm to produce RbAlH 4 by ball-milling under 20 MPa H 2 pressure for 5 h according to Scheme 4.…”

Section: Synthesis Procedures and Reagentsmentioning

confidence: 99%

Synthesis, Crystal Structure Analysis and Decomposition of RbAlH4

et al. 2018

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RbAlH 4 , a member of the complex metal aluminum hydride family, can be synthesized phase pure by different synthesis routes. Synthesis from the metals by a mechanochemical reaction requires the presence of a catalyst, but also emphasizes the reversibility of hydrogenation. The structure refinement of neutron diffraction data confirms that RbAlD 4 is isostructural to KAlD 4. The decomposition proceeds via two distinct processes at temperatures above 275 • C. However, the structures formed during decomposition seem to be different from the compounds formed during hydrogen release of early alkali metal aluminum hydrides.

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“…Moreover, the formation of MH during that period modifies the surface tension of the liquid, decreases the dispersion and acts as a catalyst. The second step consists in keeping the rotation rate of 250 rpm for 12 h. At that time, the powder is grayish, due to the presence of a low amount of highly divided free metal, which is easily transformed into MH after heating the vial at 100 • C for a few hours [12].…”

Section: Synthesis Of Alkali Metal Hydridesmentioning

confidence: 99%