Hydrogen sorption properties of MgH2/10 wt.% Graphite

V. FUSTER; F.J. CASTRO; G. URRETAVIZCAYA

Moscú, Rusia

Simposio; International Symposium on Metal-Hydrogen Systems (MH 2010); 2010

Chemistry Department of Lomonosov Moscow State University

Magnesium based systems is largely studied due to the high hydrogen capacity and low cost of this metal. Nevertheless, the drawbacks related with the slow sorption kinetics and high thermodynamic stability of the hydride still give place to many efforts dedicated to this issue. Among others, the addition of graphite is one possible choice that improves the hydrogen sorption properties of Mg. In this paper, MgH2/10 wt.% graphite prepared by reactive mechanical alloying under H2 atmosphere [1] is studied. The evolution of the desorption behaviour of samples extracted at different milling times, i.e. with different hydrogen content, is analyzed by DSC. The microstructure is studied by optical and electronic microscopy. The sorption properties are studied for different amounts of hydride in the sample by high pressure calorimetry (HPDSC) and conventional isothermal volumetric measurements. The dependence of the hydrogen desorption rate with hydrogen content is related with the reaction mechanism.  [1] V. Fuster, G. Urretavizcaya, F.J. Castro, J. Alloys Compd. (2009) 673-680.