Nanolayer-like-shaped MgFe 2 O 4 synthesised via a simple hydrothermal method and its catalytic effect on the hydrogen storage properties of MgH 2 .

In this study, the effect of nanolayer-like-shaped MgFe 2 O 4 that is synthesised via a simple hydrothermal method on the performance of MgH 2 for hydrogen storage is studied. MgH 2 + 10 wt% MgFe 2 O 4 is prepared by using the ball milling method. The MgFe 2 O 4 -doped MgH 2 sample started to release H 2 at approximately 250 °C, 90 °C and 170 °C lower than the milled and pure MgH 2 respectively. At 320 °C, the isothermal desorption kinetic study has shown that the doped sample has desorbed approximately 4.8 wt% H 2 in 10 min while the milled MgH 2 desorbed less than 1.0 wt% H 2 . For isothermal absorption kinetics, the doped sample can absorb approximately 5.5 wt% H 2 in 10 min at 200 °C. Meanwhile, the undoped sample absorbs only 4.0 wt% H 2 in the same condition. The activation energy of 10 wt% MgFe 2 O 4 -doped MgH 2 composite is 99.9 kJ mol -1 , which shows a reduction of 33.1 kJ mol -1 compared to the milled MgH 2 (133.0 kJ mol -1 ). X-ray diffraction spectra display the formation of new species which are Fe and MgO after dehydrogenation, and these new species are believed to act as the real catalyst that plays a crucial role in improving the sorption performance of the MgFe 2 O 4 -doped MgH 2 system by providing a synergetic catalytic effect.