Ameliorating the re/dehydrogenation behaviour of MgH2 by zinc titanate addition

• Published in: Journal of magnesium and alloys 2023-06, Vol.11 (6), p.2205-2215
• Main Authors: Ali, N.A., Sazelee, N.A., Md Din, M.F., Nasef, M.M., Jalil, A.A., Liu, Haizen, Ismail, M.
• Format: Article
• Language: English
• Subjects: Additive; Hydrogen storage; MgH2; Solid-state storage; Zn2TiO4
• ISSN: 2213-9567; 2213-9567
• DOI: 10.1016/j.jma.2023.05.005

Magnesium hydride (MgH2) is the most feasible and effective solid-state hydrogen storage material, which has excellent reversibility but initiates decomposing at high temperatures and has slow kinetics performance. Here, zinc titanate (Zn2TiO4) synthesised by the solid-state method was used as an additive to lower the initial temperature for dehydrogenation and enhance the re/dehydrogenation behaviour of MgH2. With the presence of Zn2TiO4, the starting temperature for the dehydrogenation of MgH2 was remarkably lowered to around 290°C–305°C. In addition, within 300 s, the MgH2–Zn2TiO4 sample absorbed 5.0 wt.% of H2 and 2.2–3.6 wt.% H2 was liberated from the composite sample in 30 min, which is faster by 22–36 times than as-milled MgH2. The activation energy of the MgH2 for the dehydrogenation process was also downshifted to 105.5 kJ/mol with the addition of Zn2TiO4 indicating a decrease of 22% than as-milled MgH2. The superior behaviour of MgH2 was due to the formation of MgZn2, MgO and MgTiO3, which are responsible for ameliorating the re/dehydrogenation behaviour of MgH2. These findings provide a new understanding of the hydrogen storage behaviour of the catalysed-MgH2 system.