Study on La–Mg based ternary system for hydrogen storage

An explorative study on the hydriding/dehydriding characteristics of the La2(Mg,Pd)17 ternary alloy, with different Pd content, is presented. All the samples were prepared by induction melting of the selected elements, characterized with scanning electron microscopy and X-ray powder diffraction, to detect present phases, and subsequently milled with a high-energy shaker apparatus. The hydrogen reaction kinetics and thermodynamics properties have been investigated by means of a volumetric Sievert’s apparatus. The measured H2 gravimetric capacity of the alloy varied with the Pd content, being the highest for the sample without Pd (>4.5 wt%). A possible correlation between the constituent phases individuated with microanalysis and the variation in the hydrogenation behaviour is proposed.

► Explorative study in the Mg-rich corner of the La–Pd–Mg ternary system.
► The studied alloys lay on the La2(Mg1−xPdx)17 compositional line.
► Higher Pd content results in lower H2 capacity, but higher equilibrium pressures.
► The highest absorbed hydrogen quantity is 4.8 wt% at 2 MPa and 310 °C.