Nano-sized TiVH catalysts unlocking high-performance hydrogen storage in magnesium hydride

MgH 2 was renowned for its exceptional gravimetric hydrogen storage capacity of 7.6 wt%. Nevertheless, its large-scale deployment has been limited by its sluggish kinetics. In this work, nano-sized bimetallic hydride TiVH was easily synthesized through a one-step mechanochemical method, and the synthesized TiVH remarkably improved the hydrogen storage properties of MgH 2 . The hydrogen desorption temperature of MgH 2  + 10 wt% TiVH composite was reduced to 195 °C, while the hydrogen absorption temperature was close to room temperature. Remarkably, the composite exhibited the release of 6.12 wt% hydrogen in merely 180 s under 310 °C, and rapidly absorbed 5.1 wt% H 2 within 100 s at 110 °C. The activation energies for hydrogen desorption and absorption of MgH 2 were reduced by 26% (142.6 kJ·mol −1 to 105.6 kJ·mol −1 ) and 39% (82.6 kJ·mol −1 to 50.5 kJ·mol −1 ), respectively, indicating a substantial improvement of MgH 2 in the hydrogen desorption and absorption kinetics. Furthermore, the composite displayed excellent cycling stability, retaining a high hydrogen storage capacity even after 30 consecutive cycles at 300 °C. These performance enhancements were attributed to the “hydrogen pump” effect, while the lattice distortion within bimetallic TiVH also effectively improved the hydrogen sorption kinetics of MgH 2 . This work provided a novel strategy for the construction of multi-component hydride nanocatalysts in enhancing the hydrogen storage property of MgH 2 and understanding the catalytic mechanism of these catalysts.