Synergistic enhancement of hydrogen storage properties in MgH2 using LiNbO3 catalyst

Extensive researches are being conducted to improve the high dehydrogenation temperature and sluggish hydrogen release rate of magnesium hydride (MgH2) for better industrial application. In this study, LiNbO3, a catalyst composed of alkali metal Li and transition metal Nb, was prepared through a direct one-step hydrothermal synthesis, which remarkably improved the hydrogen storage performance of MgH2. With the addition of 6 wt% LiNbO3 in MgH2, the initial dehydrogenation temperature decreases from 300 °C to 228 °C, representing a drop of almost 72 °C compared to milled MgH2. Additionally, the MgH2-6 wt.% LiNbO3 composite can quickly release 5.45 wt% of H2 within 13 min at 250 °C, and absorbed about 3.5 wt% of H2 within 30 min at 100 °C. It is also note that LiNbO3 shows better catalytic effect compared to solely adding Li2O or Nb2O5. Furthermore, the activation energy of MgH2-6 wt.% LiNbO3 decreased by 44.37% compared to milled MgH2. The enhanced hydrogen storage performance of MgH2 is attributed to the in situ formation of Nb-based oxides in the presence of LiNbO3, which creates a multielement and multivalent chemical environment.