Enhanced hydrogen sorption kinetics of magnesium by destabilized MgH2-δ

被引：73

作者：

Borgschulte, A. ^{[1
]}

Boesenberg, U. ^{[1
]}

Barkhordarian, G. ^{[1
]}

Dornheim, M. ^{[1
]}

Bormann, R. ^{[1
]}

机构：

[1] GKSS Forschungszentrum Geesthacht GmbH, Mat Res Inst, D-21502 Geesthacht, Germany

来源：

CATALYSIS TODAY | 2007年 / 120卷 / 3-4期

关键词：

catalyzed MgH2; oxide; hydrogen sorption kinetics; intermediate phase; DSC; XRD;

D O I：

10.1016/j.cattod.2006.09.031

中图分类号：

O69 [应用化学];

学科分类号：

081704 ;

摘要：

The kinetics of the reversible reaction of hydrogen gas with magnesium forming MgH2 is enhanced significantly by the addition of transition metals oxide catalysts and by using nanostructured powders. Hydrogen absorption and desorption properties of such systems were studied by differential scanning calorimetry (DSC) under hydrogen atmosphere, from which the heat of hydride formation and decomposition is determined. Apart from Mg and stoichiometric MgH2, we find an additional, slightly destabilized phase, which is formed prior to MgH2 upon hydrogenation. The amount of this phase depends on the degree of nanostructuring and the used additive. X-ray diffraction measurements confirm the compared to MgH2 slightly different lattice parameters of the intermediate phase. The results correspond to recent neutron diffraction measurements, by which a new MgH2-delta phase was found. We propose that this destabilized phase acts as a gateway for de-hydrogenation of MgH2. (c) 2006 Elsevier B.V. All rights reserved.

引用

页码：262 / 269

页数：8

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