Oxygen Vacancy-Rich Ti2NTix MXene as a High-Efficiency Catalyst for Enhanced Hydrogen Desorption of MgH2

As a prominent catalyst in the development of MgH 2 hydrogen storage materials, MXene can significantly enhance hydrogen storage performance. In this study, we investigated the impact of using molten salts instead of HF to treat Ti 2 NTi x and its impact on the hydrogen storage properties of MgH 2 . MgH 2 -10 wt% Ti 2 NTi x composite has been prepared via ball milling. The results showed that adding 10   wt% Ti 2 NTi x largely lowered the initial dehydrogenation temperature of MgH 2 from 300.2 ℃ to 173.5 ℃. Under isothermal conditions at 350 ℃, the composite released 6.11   wt% H 2 within 4   minutes. Furthermore, after dehydrogenation, the MgH 2 -10 wt% Ti 2 NTi x composite absorbed 3.4   wt% H 2 in 60   minutes at 100 ℃ and 30   bar hydrogen pressure. EPR found that there is a large number of oxygen vacancies on the Ti 2 NTi x surface introduced by molten salt treatment, providing abundant active sites and accelerating electron transfer. Additionally, the in-situ formation of titanium nitride compounds, the synergistic multivalent catalytic effect of titanium, and the multiphase interfaces in MgH 2 -10 wt% Ti 2 NTi x contributed to the composite’s improved catalytic activity and stability. This work provided valuable insights into the application of oxygen vacancy-rich, incompletely etched Ti 2 NTi x materials in magnesium-based hydrogen storage, demonstrating their great potential in hydrogen storage technologies.