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@NiMoO4 composite catalyst was prepared through a facile hydrothermal reaction. Subsequently, NiO@NiMoO4 was doped into MgH2 by ball milling to solve the problems of high dehydrogenation temperature and slow desorption kinetics of MgH2. It can be seen from the experimental results that the MgH2 + 10 wt% NiO@NiMoO4 composite starts to dehydrogenate at about 190 degrees C, which is about 170 degrees C lower than that of pure MgH2. Meanwhile, after complete dehydrogenation, the composites can start to absorb hydrogen below 40 degrees C. Compared with pure MgH2, 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 MgH2 + 10 wt% NiO@NiMoO4 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 Mg2Ni/Mg2NiH4 synergistically promote the adsorption and dissociation of hydrogen. This new synergistic mechanism provides new comprehen-sive insights for improving reversible hydrogen storage in MgH2.(c) 2022 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.

Automated summary

A novel hydrangea-like NiO@NiMoO4 composite catalyst was prepared and doped into MgH2 to address the high dehydrogenation temperature and slow kinetics of MgH2. The composite showed improved hydrogen desorption and absorption properties compared to pure MgH2. The addition of biomass charcoal further enhanced the hydrogen storage capacity.