Synergistic catalytic effects of Ti0.10Zr0.15V0.35Cr0.10Ni0.30 alloy and Pd/C composites on MgH2 hydrogen storage properties

Magnesium hydride (MgH 2 ) suffers from sluggish kinetics and high operational temperatures, hindering practical hydrogen storage. We pioneer a spatially decoupled catalytic strategy that assigns distinct roles to Ti 0 . 10 Zr 0 . 15 V 0 . 35 Cr 0 . 10 Ni 0 . 30 (TA) alloy (bulk diffusion promoter) and Pd/C (surface dissociation catalyst), overcoming the inherent coupling of rate-limiting steps in MgH 2 . This design achieves near-ambient absorption (4.56 wt% at 100 °C) and eliminates activation cycles—a milestone unattained by single-catalyst systems. Kissinger analysis confirms a 46.0% reduction in activation energy (78.8 kJ/mol) for the surface-limited step, directly validating the spatial separation of catalytic functions. Crucially, the composite retains 92.3% capacity after 30 cycles with negligible kinetic degradation (0.40% decay/cycle), eliminating the need for activation. This work establishes a spatially coupled catalytic mechanism that decouples surface and bulk processes, enabling a lower operating temperature for MgH 2 .