Hydrogen storage behaviors of magnesium hydride catalyzed by transition metal carbides

In this study, some transitional metal carbides (Ti 3 C 2 , Ni 3 C, Mo 2 C, Cr 3 C 2 and NbC) were prepared to enhance the hydrogen storage behaviors of magnesium-based materials. The carbides with a weight ratio of 5 wt% were introduced into magnesium hydride (MgH 2 ) by mechanical ball milling , and the microstructure, phase composition and hydrogen storage properties of the composites were studied in detail. The phase compositions of Ni 3 C, Mo 2 C, Cr 3 C 2 and NbC in the ball-milled composites have not changed during hydrogen absorption and desorption cycles. However, Ti 3 C 2 decompose into multivalent Ti during hydrogenation process . All of these metal carbides can enhance the hydrogen absorption and desorption kinetics of MgH 2 . Among them, Ti 3 C 2 shows the best catalytic effect on dehydrogenation kinetic properties of MgH 2 , followed by the Ni 3 C, NbC, Mo 2 C and Cr 3 C 2 .