For the first time, the MgH₂–NaAlH₄ (ratio 4:1) destabilized system with CoTiO₃ addition has been explored. The CoTiO₃-doped MgH₂–NaAlH₄ sample begins to dehydrogenate at 130 ℃, which is declined by 40 ℃ compared to the undoped MgH₂–NaAlH₄. Moreover, the de/rehydrogenation kinetics characteristics of the CoTiO₃-doped MgH₂–NaAlH₄ were greatly ameliorated. With the inclusion of CoTiO₃, the MgH₂–NaAlH₄ composite absorbed 5.2 wt.% H₂, higher than undoped MgH₂–NaAlH₄. In the context of dehydrogenation, the CoTiO₃-doped MgH₂–NaAlH₄ sample desorbed 2.6 wt.% H₂, almost doubled compared to the amount of hydrogen desorbed from the undoped MgH₂–NaAlH₄ sample. The activation energy obtained by the Kissinger analysis for MgH₂ decomposition was significantly lower by 35.9 kJ/mol than the undoped MgH₂–NaAlH₄ sample. The reaction mechanism demonstrated that new phases of MgCo and AlTi₃ were generated in situ during the heating process and are likely to play a substantial catalytic function and be useful in ameliorating the de/rehydrogenation properties of the destabilized MgH₂–NaAlH₄ system with the inclusion of CoTiO₃.

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.