MXene-supported VHx nanoparticles enhancing hydrogen storage properties of magnesium hydride

• Reduces onset dehydrogenation temperature of MgH2 from 267.6°C to 190.3°C with 10wt% VHx@Ti3C2. • Achieves rapid hydrogen release of 6.72wt% within 10 min at 290°C, compared to only 0.29wt% for pure MgH2. • Maintains over 95% of initial hydrogen absorption/desorption capacity after 20 cycles, demonstrating excellent cycling stability. • Unveils dual catalytic mechanism: layered Ti3C2 provides abundant active sites, while VHx acts as a "hydrogen pump" accelerating H-ion migration.