Fabrication of V2O3-TiO2-rGO ternary heterojunction composite to enhance the hydrogen storage performance of MgH2

The application prospects of MgH 2 as a potential solid hydrogen storage material are limited by its stable thermodynamic properties and slow hydrogenation/dehydrogenation kinetics. In this study, a ternary heterogeneous composite material V 2 O 3 -TiO 2 -rGO (V-T-rGO) was synthesized using the ultrasonic hydrothermal method and doped into MgH 2 through ball milling to improve its hydrogen storage performance. The experimental results demonstrated that the MgH 2  + V-T-rGO samples exhibit superior hydrogen storage properties compared with single-doped V 2 O 3 , TiO 2 , rGO or V-T materials. Specifically, it can uptake hydrogen at room temperature, and adsorbs 5.00 wt% H 2 in just 4 min at 150 °C, and releases 5.87 wt% H 2 within 6 min at 325 °C, demonstrating a faster reaction rate and successful hydrogen absorption. Additionally, the hydrogenation/dehydrogenation activation energies of MgH 2  + V-T-rGO samples are measured at 27.1/72.3 kJ·mol −1 , representing a reduction of 51.2/59.2 kJ·mol −1 compared to MgH 2 alone. Mechanistic analysis revealed that the multiphase composite system produced synergistic catalytic effects, providing abundant active sites and hydrogen diffusion channels to enhance the hydrogen storage performance of MgH 2 . This study presents an innovative approach for constructing transition metal oxide heterostructured materials and holds significant reference value for applications in the field of hydrogen storage.