Express penetration of hydrogen on Mg(10͞13) along the close-packed-planes

Abstract

Metal atoms often locate in energetically favorite close-packed planes, leading to a relatively high penetration barrier for other atoms. Naturally, the penetration would be much easier through non-close-packed planes, i.e. high-index planes. Hydrogen penetration from surface to the bulk (or reversely) across the packed planes is the key step for hydrogen diffusion, thus influences significantly hydrogen sorption behaviors. In this paper, we report a successful synthesis of Mg films in preferential orientations with both close- and non-close-packed planes, i.e. (0001) and a mix of (0001) and (103), by controlling the magnetron sputtering conditions. Experimental investigations confirmed a remarkable decrease in the hydrogen absorption temperature in the Mg (103), down to 392 K from 592 K of the Mg film (0001), determined by the pressure-composition-isothermal (PCI) measurement. The ab initio calculations reveal that non-close-packed Mg(103) slab is advantageous for hydrogen sorption, attributing to the tilted close-packed-planes in the Mg(103) slab.

Nanolayer-like-shaped MgFe2O4 synthesised via a simple hydrothermal method and its catalytic effect on the hydrogen storage properties of MgH2

“…Fig. 5 2 . From the images, it can be seen clearly that the particle size of the pure MgH 2 is around 50-100 mm (Fig.…”

“…However, MgH 2 is restricted by the decomposition temperature, which is high with slow sorption kinetics and is excessively stable thermodynamically. 2 Many research have been conducted to overcome these disadvantages by altering the thermodynamics and improve the kinetic properties by producing nanostructures 3,4 and utilizing catalysts such as carbon-based materials, 5,6 metals, 7-10 metal hydrides, 11,12 metal oxides, [13][14][15][16][17][18] metal halides, [19][20][21] and nanosized alloys.…”

Severely deformed ZK60 + 2.5% Mm alloy for hydrogen storage produced by two different processing routes

“…An additional effect to explain the better hydrogenation properties of CR specimens could also have come from the orientation of the grains. As recently reported by Ouyang et al [42], the hydrogen sorption properties of Mg were clearly correlated with its crystal orientation. The authors studied films prepared by magnetron sputtering and found that the hydrogenation of ð1013Þ planes required less energy than (0001) planes, thus faster diffusion originated from this facet effect.…”

An investigation on hydrogen storage thermodynamics and kinetics of Nd–Mg–Ni-based alloys synthesized by mechanical milling

“…Many hydrogen storage materials have been reported for achieving the application goal, but unfortunately, none of them can meet all the performance requirements proposed by U.S. Department of Energy (DOE) for vehicular applications [6,7]. As far as hydrogen absorption capacity is concerned, Mgbased alloys are regarded as one of the most attractive candidates for hydrogen-fuel-cell vehicle or for nickel-metal hydride (Ni-MH) batteries as negative electrode materials [8,9]. Most of the papers published by International Symposium on Metal Hydrogen System Fundamental and Applications, Manchester, UK, July 2014 (MH2014) still concentrate on the investigation of Mg-based hydrogen storage alloy.…”