The catalytic effects of UiO-66 on enhancing hydrogen storage performance of MgH2

This study demonstrates the improved hydrogen storage performance of magnesium hydride (MgH₂) through the incorporation of a zirconium-based metal-organic framework (MOF), UiO-66. The addition of UiO-66 significantly enhances the sorption kinetics and reduces the decomposition temperature to below 400 °C. Synthesized via a solvothermal route and stabilized by post-calcination at 300 °C, UiO-66 exhibits excellent thermal and chemical stability, making it a promising additive for hydrogen storage systems. The MgH₂/UiO-66 composite shows an initial dehydrogenation temperature of 262 °C, which is 80 °C lower than that of milled MgH₂. The apparent activation energy is reduced to 85.5 ± 5.5 kJ/mol, approximately 45 % of the pristine MgH₂, indicating a significantly enhanced reaction pathway. At 250 °C, the composite achieves a hydrogen capacity of approximately 6.8 wt% within 3600 s and maintains stable performance over ten consecutive cycles. Particle size analysis via scanning electron microscopy (SEM) reveals finer dispersion and reduced agglomeration in the composite compared to milled MgH₂ alone. The MgH₂/UiO-66 system effectively functions as a “hydrogen pump,” facilitating faster hydrogenation/dehydrogenation kinetics and improved cycling stability. Hence, this study offers fresh insights to expand research and accelerate the advancement of hydrogen energy.