Multiphase catalytic system enhancement of hydrogen storage performance in MgSc alloy via nanosheet-clustered NiO

Catalytic modification can effectively reduce the kinetic barriers and enhance the reaction rate of Mg-based hydrogen storage materials. In this study, nanosheet-clustered NiO catalyst is synthesized and incorporated into MgSc solid solution alloy. The hydrogen de/sorption properties are optimized through the effects of in-situ generated nanocatalysts and external addition catalysts. Results indicate the in-situ formation of nanosized ScH 2 catalytic phases within MgSc alloy matrix, along with the generation of Mg 2 Ni/Mg 2 NiH 4 nanophases through the reaction between NiO and Mg. In addition, a small amount of Ni maintains nanoparticles morphology through stabilization by Ni/MgO coupling effect. At 300 °C, the hydrogen storage capacity of 5 wt% NiO-modified is reached at 5.44 wt%. And the dehydrogenation capacity achieves 3.05 wt% within 5 min. The formation of multiphase interfaces during hydrogenation establishes both abundant hydrogen diffusion channels and high-density active sites. In addition, dehydrogenation performance is remarkably enhanced by the synergistic catalytic between Ni-mediated hydrogen spillover and the hydrogen pump effect of ScH 2 and Mg 2 Ni/Mg 2 NiH 4 . • Multiphase catalytic system is formed by in-situ ScH 2 and external NiO catalyst. • At 300°C, NiO-5 (capacity 5.44 wt%) release 3.05 wt% H 2 within 5 min. • Part of Ni is retained as elemental nanoparticles under Ni/MgO coupling effect. • Multiphase synergistic effect accelerates the release of hydrogen.