Enhancement of hydrogen storage properties by in situ formed LaH3 and Mg2NiH4 during milling MgH2 with porous LaNiO3

In this study, we reported that a porous perovskite LaNiO3 prepared by a precipitation-combustion method exhibited significant catalytic effect on hydrogen storage properties of Mg. It is demonstrated that the optimal H-absorption property was achieved on the composite containing 10 wt.% porous LaNiO3 with a milling time of 10 h, 5.1 wt.% hydrogen can be absorbed within 1.0 min at 200 degrees C. The activation energy of hydrogenation of the composite is ca. 7.05 kJ/mol H-2 and the rate-controlling step is controlled by H-diffusion at a temperature higher than 200 degrees C. SEM, XRD and XPS results indicated that the prominent hydrogen storage properties of MgH2 catalyzed by the porous LaNiO3 are resulted from the uniform distribution of porous LaNiO3 with high BET surface in the matrix of MgH2 as well as the synergistic catalytic effect of LaH3 and Mg2NiH4 formed in situ at the hydrogenation process.