Effect of porous nanosheet NiO on hydrogen storage performance of MgH2

In the field of solid hydrogen storage , Magnesium hydride (MgH 2 ) is the promising material. However, the practical application was hindered due to slow kinetics performance and unfavorable thermodynamic property. In this study, porous nanosheet NiO was prepared by the calcination of Ni(OH) 2 synthesized using the hydrothermal way and subsequently introduced in MgH 2 by ball milling . The resulting MgH 2 -5 wt% NiO material conveyed significantly enhanced hydrogen storage property. The initial dehydrogenation temperature was decreased to 210 °C, which is 114 °C lower than that of Ball-milling MgH 2 . The MgH 2 -5 wt% NiO released 6.4 wt% H 2 within 10 min at 300 °C.And at room temperature it begins to uptake hydrogen. The MgH 2 -5 wt% NiO composite also displayed excellent cyclic stability, retaining the 96.2 % of capacity retention rate after 40 cycles. Furthermore, added NiO catalyst reduced the hydrogen desorption activation energy of MgH 2 from 133.69 ± 12.55 kJ/mol to 81.47 ± 7.48 kJ/mol. The superior performance owed to the in-situ generation of Mg 2 Ni/Mg 2 NiH 4 during the reaction between NiO and MgH 2 . These intermediates act as the “hydrogen pump,” weakening the Mg–H bond strength to improving the hydrogen storage properties of MgH 2 . This study displays that the catalyst of porous nanosheet NiO can obviously better the hydrogen storage property of MgH 2 , making it a more viable candidate for practical applications.