Nanolayer-like-shaped MgFeO Synthesised a Simple Hydrothermal Method and Its Catalytic Effect on the Hydrogen Storage Properties of MgH

In this study, the effect of nanolayer-like-shaped MgFeO that is synthesised a simple hydrothermal method on the performance of MgH for hydrogen storage is studied. MgH + 10 wt% MgFeO is prepared by using the ball milling method. The MgFeO-doped MgH sample started to release H at approximately 250 °C, 90 °C and 170 °C lower than the milled and pure MgH respectively. At 320 °C, the isothermal desorption kinetic study has shown that the doped sample has desorbed approximately 4.8 wt% H in 10 min while the milled MgH desorbed less than 1.0 wt% H. For isothermal absorption kinetics, the doped sample can absorb approximately 5.5 wt% H in 10 min at 200 °C. Meanwhile, the undoped sample absorbs only 4.0 wt% H in the same condition. The activation energy of 10 wt% MgFeO-doped MgH composite is 99.9 kJ mol, which shows a reduction of 33.1 kJ mol compared to the milled MgH (133.0 kJ mol). 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 MgFeO-doped MgH system by providing a synergetic catalytic effect.