Hydrogen Storage Property Comparison of Pure Mg and Iron (III) Oxide-Added Mg Prepared by Reactive Mechanical Grinding

Abstract

The activation of Mg-10 wt%Fe2O3 was completed after one hydriding-dehydriding cycle. Activated Mg-10 wt%Fe2O3 absorbed 5.54 wt% H for 60 min at 593 K under 12 bar H2, and desorbed 1.04 wt% H for 60 min at 593 K under 1.0 bar H2. The effect of the reactive grinding on the hydriding and dehydriding rates of Mg was weak. The reactive grinding of Mg with Fe2O3 is believed to increase the H2-sorption rates by facilitating nucleation (by creating defects on the surface of the Mg particles and by the additive), by making cracks on the surface of Mg particles and reducing the particle size of Mg and thus by shortening the diffusion distances of hydrogen atoms. The added Fe2O3 and the Fe2O3 pulverized during mechanical grinding are considered to help the particles of magnesium become finer. Hydriding-dehydriding cycling is also considered to increase the H2-sorption rates of Mg by creating defects and cracks and by reducing the particle size of Mg.