Graphene-anchored Ni6MnO8 nanoparticles with steady catalytic action to accelerate the hydrogen storage kinetics of MgH2

Transition metal-based oxides have been proven to have a substantial catalytic influence on boosting the hydrogen sorption performance of MgH 2 . Herein, the catalytic action of Ni 6 MnO 8 @rGO nanocomposite in accelerating the hydrogen sorption properties of MgH 2 was investigated. The MgH 2  + 5 wt% Ni 6 MnO 8 @rGO composites began delivering H 2 at 218 °C, with about 2.7 wt%, 5.4 wt%, and 6.6 wt% H 2 released within 10 min at 265 °C, 275 °C, and 300 °C, respectively. For isothermal hydrogenation at 75 °C and 100 °C, the dehydrogenated MgH 2  + 5 wt% Ni 6 MnO 8 @rGO sample could absorb 1.0 wt% and 3.3 wt% H 2 in 30 min, respectively. Moreover, as compared to addition-free MgH 2 , the de/rehydrogenation activation energies for doped MgH 2 composites were lowered to 115 ± 11 kJ/mol and 38 ± 7 kJ/mol, and remarkable cyclic stability was reported after 20 cycles. Microstructure analysis revealed that the in-situ formed Mg 2 Ni/Mg 2 NiH 4 , Mn, MnO 2 , and reduced graphene oxide synergically enhanced the hydrogen de/absorption properties of the Mg/MgH 2 system.