Effect of LaFeO3 on hydrogenation/dehydrogenation properties of MgH2

LaFeO3 was used to improve the hydrogen storage properties of MgH2. The MgH2+20 wt.%LaFeO3 composite was prepared by ball milling method. The composite could absorb 3.417 wt.% of hydrogen within 21 min at 423 K while MgH2 only uptaked 0.977 wt.% hydrogen under the same conditions. The composite also released 3.894 wt.% of hydrogen at 623 K, which was almost twice more than MgH2. The TPD measurement showed that the onset dissociation temperature of the composite was 570 K, 80 K lower than the MgH2. Based on the Kissinger plot analysis of the composite, the activation energy Edes was estimated to be 86.69 kJ/mol, which was 36 kJ/mol lower than MgH2. The XRD and SEM results demonstrated that highly dispersed LaFeO3 could be presented in MgH2, benefiting the reduction of particle size and also acting as an inhibitor to keep the particles from clustering during the ball-milled process.

Graphical AbstractTemperature-pressure-desorption curves of the MgH2+20 wt.%LaFeO3 composite and MgH2Figure optionsDownload full-size imageDownload as PowerPoint slide