A fancy hydrangea shape bimetallic Ni-Mo oxide of remarkable catalytic effect for hydrogen storage of MgH2

The design of catalysts with excellent catalytic activity plays an important role in the field of solid-state hydrogen storage of new energy sources. Herein, a novel hydrangea-like NiO@NiMoO 4 composite catalyst was prepared through a facile hydrothermal reaction. Subsequently, NiO@NiMoO 4 was doped into MgH 2 by ball milling to solve the problems of high dehydrogenation temperature and slow desorption kinetics of MgH 2 . It can be seen from the experimental results that the MgH 2  + 10 wt% NiO@NiMoO 4 composite starts to dehydrogenate at about 190 °C, which is about 170 °C lower than that of pure MgH 2 . Meanwhile, after complete dehydrogenation, the composites can start to absorb hydrogen below 40 °C. Compared with pure MgH 2 , the activation energy of hydrogen absorption and dehydrogenation of the composite decreased by 47.6 kJ/mol and 46.5 kJ/mol, respectively. In 10th cycle tests, the MgH 2  + 10 wt% NiO@NiMoO 4 composite still has good cycle stability. After adding a small amount of biomass charcoal, the hydrogen storage capacity can even be maintained above 97%. Furthermore, the characterization results show that the in situ generated new species Mo and Mg 2 Ni/Mg 2 NiH 4 synergistically promote the adsorption and dissociation of hydrogen. This new synergistic mechanism provides new comprehensive insights for improving reversible hydrogen storage in MgH 2 .