Catalytic effect of a novel MgC0.5Co3 compound on the dehydrogenation of MgH2

The application of magnesium hydride (MgH 2 ) is limited due to the high reaction temperature and slow kinetics during dehydrogenation. In order to ameliorate the dehydrogenation property of MgH 2 , MgC 0.5 Co 3 compound with induction and catalytic effects was introduced into the Mg/MgH 2 system via ball-milling and hydriding combustion methods in present study. Compared to the pure MgH 2 , the initial hydrogen desorption temperature of MgH 2 –MgC 0.5 Co 3 composite lowered to 237 ​°C, decreasing by 141 ​°C. At 325 ​°C the MgH 2 –MgC 0.5 Co 3 composite could release 4.38 ​wt% H 2 within 60 ​min, which is 4.5 times the capacity of hydrogen released by as milled-MgH 2 . Besides, the hydrogen desorption activation energy of the MgH 2 –MgC 0.5 Co 3 composite was dramatically reduced to 126.7 ​± ​1.4 ​kJ/mol. It was observed that MgC 0.5 Co 3 was chemically stable and no chemical transformation occurred after cycling, which not only inhibited the nucleation and growth of composite particles, but also had a positive effect on the hydrogen desorption reaction of MgH 2 due to its catalytic effect. This study may provide references for designing and synthesizing Mg–C–Co alloy compound for the Mg-based hydrogen storage area.