Correlation between hydrogen storage properties and amount of alloy particles in Mg-based composites

The results obtained from the systematic investigation of the effect of amount of alloy particles in Mg + x wt% (Ti0.1Zr0.9)1.1Mn0.9V0.1Fe0.5Ni0.5 (x = 5, 15, 25, 30, 35, 40, 50, 60 and 75) on the hydrogen storage properties have been discussed. Mg + x wt% (Ti0.1Zr0.9)1.1Mn0.9V0.1Fe0.5Ni0.5 (x = 5, 15, 25, 30, 35, 40, 50, 60 and 75) composites have been synthesized by reaction ball milling. The composites have been characterized by powder X-ray diffractograms (XRD) and scanning electron microscopy (SEM). To examine the effect of amount of catalyst on the hydrogen storage properties of these composites, pressure-composition absorption/desorption isotherms have been obtained in the pressure range 0.1-100 bar at 300 °C using pressure reduction technique. Maximum storage capacity of around 4.7 wt% at 300 °C has been obtained in Mg + 5 wt% (Ti0.1Zr0.9)1.1Mn0.9V0.1Fe0.5Ni0.5. The dependence of plateau pressure on the unit cell volume of Mg phase in these composites is discussed. Hydrogen absorption kinetics of these materials were performed at 300 °C. The kinetics data were analyzed using rate equations to understand the mechanism of hydriding reaction process.