Alloy-type Mo single-atom catalyst enhancing hydrogen storage performance of MgH₂

Metallic single-atom catalysts (SACs) have demonstrated high activity and potential in enhancing the hydrogen storage properties of MgH₂. However, previous reports primarily focus on supported SACs, which often suffer from insufficient contact between single-atom active sites and hydrogen storage materials. In this study, the precursor Mo(CO)₆ is uniformly dispersed on the surface of MgH₂ via impregnation adsorption, leading to the formation of alloy-type Mo single atoms after hydrogenation/dehydrogenation activation. This alloy structure enables zero-distance contact between catalytic sites and the hydrogen storage material, facilitating electron exchange and hydrogen transfer between the Mo sites and MgH₂. The MgH₂ loaded with Mo single atoms (Mo₁-MgH₂) exhibits excellent hydrogen absorption and desorption properties, with the initial hydrogen release temperature lowered from 323 to 218 °C. At 250 °C, Mo₁-MgH₂ absorbs over 6.77 wt% of hydrogen within 1 min and releases over 5.85 wt% within 4 h. During 10 cycles of hydrogenation and dehydrogenation reactions, Mo₁-MgH₂ maintains nearly 100% capacity and shows stable kinetics. This work provides new insights into the design and fabrication of catalysts for hydrogen storage materials.