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.