Effect of Ti-EG-Ni Dual-Metal Organic Crystal-Derived TiO2/C/Ni on the Hydrogen Storage Performance of MgH2

To effectively address the kinetic sluggishness associated with MgH2, this study utilized Ti–EG–Ni dual-metal organic crystal as precursors and employed carburization to prepare the unique rod-shaped structure TiO2/C/Ni. The catalyst was incorporated into MgH2 by ball milling, demonstrating excellent hydrogen storage performance. The composite of MgH2–8 wt % TiO2/C/Ni exhibited a lower initial dehydrogenation temperature of 185 °C and a marked dehydrogenation activation energy of 60.537 kJ/mol. At 300 and 150 °C, it only required 300 s to release 6.17 wt % H2 and absorb 5.72 wt % H2 within 20 s, respectively. Additionally, the composites demonstrated excellent cycling stability, maintaining 94% reversible capacity after 50 cycles. Theoretical computations suggested that the in situ-generated metal Mg2Ni and semiconductor TiO2 created a Schottky heterojunction, which stimulated an internal electric field between Ni and TiO2, accelerating electron transfer. The strong electronic interaction between the catalyst and MgH2 weakened the Mg–H bond energy and elongated the Mg–H bond, promoting hydrogen dissociation. During hydrogen absorption and desorption, the composite material exhibited excellent hydrogen storage performance due to the uniform distribution of elements, the in situ-generated catalytic active sites (multivalent Ti and Mg2Ni/Mg2NiH4), and the support provided by carbon to the nanostructures. Our findings provide a deeper understanding of how highly active catalysts of metal oxides/C/Ni enhance the hydrogen storage performance of MgH2.