On the barriers limiting the reaction kinetics between catalysed Mg and hydrogen

Montone, A.; Aurora, Annalisa; Gattia, Daniele Mirabile; Antisari, M. Vittori

doi:10.1016/j.scriptamat.2010.05.003

Cited by 29 publications

(14 citation statements)

References 19 publications

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“…After several cycling, the internal material appears to come out from the particle surface, giving rise to worm-like structures where no catalyst particles are present. Similar microstructural evolution is observed for as milled [22] and cycled pure MgH 2 powder (Figure 5d). In particular the extent of protrusion is comparable to the catalyzed sample with the same number of cycles as well as the size of the agglomerates.…”

Section: Resultssupporting

confidence: 79%

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Microstructural and Kinetic Evolution of Fe Doped MgH2 during H2 Cycling

et al. 2012

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The effect of extended H 2 sorption cycles on the structure and on the hydrogen storage performances of MgH 2 powders with 5 wt% of Fe particle catalyst is reported. MgH 2 powders with and without Fe have been ball milled under Argon, the doped MgH 2 nanocomposite has been cycled under hydrogen pressure up to a maximum of 47 desorption and absorption cycles at 300 °C. After acceleration during the first 10 cycles, the kinetics behavior of doped MgH 2 is constant after extended cycling, in terms of maximum storage capacity and rate of sorption. The major effect of cycling on particle morphology is the progressive extraction of Mg from the MgO shell surrounding the powder particles. The Mg extraction from the MgO shell leaves the catalyst particles inside the hydride particles. Many empty MgO shells are observed in the pure ball milled MgH 2 upon cycling at higher temperature, suggesting that this enhancement of the extraction efficiency is related to the higher operating temperature which favors Mg diffusivity with respect to the H ion one.

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Section: Resultssupporting

confidence: 79%

“…The value of n in the range from 0.5 to 1 suggests a transformation at constant density of MgH 2 nuclei and controlled by limited hydrogen flux at the powder particle surface [22]. In the case of desorption reaction, the process is influenced by the presence of Fe.…”

Section: Resultsmentioning

confidence: 99%

Microstructural and Kinetic Evolution of Fe Doped MgH2 during H2 Cycling

et al. 2012

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“…Montone A et al [41] later investigated the process of catalyzed Mg reacting with hydrogen to give MgH 2 . The results suggested that the process of the newly grown MgH 2 phase was interface-controlled, and the surface of the sample served as the factor limiting the hydrogen flue supplied to the reaction.…”

Section: Catalystsmentioning

confidence: 99%

“…The limiting factor may be related to the step of splitting the hydrogen molecule on the Mg surface or to the further diffusion through the oxide hydroxide layer which forms on the Mg surface. By adding a catalyst on the surface of the material, it is possible to effectively increase the hydrogen concentration on the surface of the material, thereby accelerating the progress of the reaction [41]. When the reaction rate is increased, the absorption and desorption processes of the catalyzed material can be carried out at lower temperatures compared to the non-catalyzed material [22].…”

Section: Catalystsmentioning

confidence: 99%

A Critical Review of Mg-Based Hydrogen Storage Materials Processed by Equal Channel Angular Pressing

Lisha

Jiang

et al. 2017

Metals

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Abstract:As a kind of cost-efficient hydrogen storage materials with high hydrogen capacity and light weight, Mg-based alloys have attracted much attention. This review introduces an effective technique in producing bulk ultrafine-grained (UFG) Mg alloys and promoting its hydrogen storage property, namely, equal-channel angular pressing (ECAP). This paper briefly describes the technical principle of ECAP and reviews the research progress on hydrogen storage properties of ECAP-processed Mg alloys. Special attention is given to their hydrogen storage behaviors including hydrogen storage dynamics, capacity, and cycling stability. Finally, it analyzes the factors that affect the hydrogen storage properties of ECAP-processed Mg alloys, such as the grain sizes, lattice defects, catalysts, and textures introduced by ECAP process.

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“…Ball milling [4] and catalysis [4e8] are the most effective techniques. The mechanism of catalytic action and the most effective loci of catalyst atoms were studied in papers [9,10]. As a catalyst, transition metals [11e13] and their oxides [14e18] were used.…”

Section: Introductionmentioning

confidence: 99%