LaFeO3 synthesised by solid-state method for enhanced sorption properties of MgH2

Abstract

Environment pollution becomes more serious in recent years. Thus, hydrogen energy has been considered as a suitable energy carrier due to its renewability, clean and environmentally friendly. In the application of hydrogen energy, there are problems in the storage which need to be solved. Therefore, the aim of this research is to enhance the hydrogen storage performance of MgH2 by the addition of LaFeO3 as a catalyst through ball milling technique. The result showed that the LaFeO3-doped MgH2 appeared to have a better performance on the sorption properties compared to the MgH2 samples. For the onset desorption temperature, the temperature was reduced from 420 °C (as received MgH2) to 300 °C (LaFeO3-doped MgH2). In addition, the LaFeO3-doped MgH2 sample was able to desorb about 3.7 wt% of H2 within 15 min at 320 °C, while the undoped sample just released 1.4 wt% of H2 under the same condition. For the absorption kinetics, the LaFeO3-doped MgH2 and milled MgH2 sample had absorbed about 6.1 wt% and 4.1 wt% of H2 within 30 min, respectively. The activation energy of the doped sample showed a reduction to 107 kJ/mol, which revealed an improvement in kinetics. The existence of in situ MgO, La2O3 and Fe strongly affected the hydrogenation performance of MgH2 that led to the enhancement of the hydrogen storage properties of MgH2.

Keywords

• Magnesium hydride
• Hydrogen storage
• Catalyst
• Lanthanum iron oxide