Cu3(VO4)2 bimetallic catalyst collaboratively improves the hydrogen storage performance of MgH2

MgH2 as a solid hydrogen storage substance has wide application prospects in future energy systems. This study investigates the role of Cu3(VO4)2 as a bimetallic catalyst in enhancing the hydrogen storage performance of MgH2. The Cu3(VO4)2 was reduced to Mg2Cu, MgCu2 and VO active sites during hydrogen absorption and release by reaction induction, creating a richer catalytic environment for the system. These active sites play an important role in promoting hydrogen dissociation, binding and diffusion. In particular, the synergistic effect of V species (VO) and Cu species (Mg2Cu, MgCu2) in overcoming the paradoxical relationship between hydrogen dissociation and diffusion. As a result, the MgH2-6wt.%Cu3(VO4)2 composite is capable of liberating 4.3 wt% H2 within 60 min at 200 °C and further releasing 5.3 wt% within 30 min at 220 °C, in addition to absorbing 4.44 wt% H2 within 15 min at 100 °C. After 65 cycles, the hydrogen absorption and desorption amount of MgH2-6wt.%Cu3(VO4)2 composite are 5.67 wt% and 5.6 wt% respectively, with a reversible hydrogen storage capacity preserved at 94 %. This investigation reveals the cooperative catalytic effect of Cu/V bimetallic oxide catalyst on the kinetic attributes of Mg/MgH2, and provides a possibility for developing practical magnesium hydrogen storage materials.