Hydrogen Storage Properties of Pure MgH2

The hydrogen storage properties of pure MgH 2 were studied and compared with those of pure Mg.At the first cycle, pure MgH 2 absorbed hydrogen very slowly at 573 K under 12 bar H 2 .The activation of pure MgH 2 was completed after three hydriding-dehydriding cycles.At the 4 th cycle, the pure MgH 2 absorbed 1.55 wt% H for 5 min, 2.04 wt% H for 10 min, and 3.59 wt% H for 60 min, showing that the activated MgH 2 had a much higher initial hydriding rate and much larger H a (60 min), quantity of hydrogen absorbed for 60 min, than did activated pure Mg.The activated pure Mg, whose activation was completed after four hydriding-dehydriding cycles, absorbed 0.80 wt% H for 5 min, 1.25 wt% H for 10 min, and 2.34 wt% H for 60 min.The particle sizes of the MgH 2 were much smaller than those of the pure Mg before and after hydridingdehydriding cycling.The pure Mg had larger hydrogen quantities absorbed at 573K under 12 bar H 2 for 60 min, H a (60 min), than did the pure MgH 2 from the number of cycles n = 1 to n = 3; however, the pure MgH 2 had larger H a (60 min) than did the pure Mg from n = 4 to n = 6.