<bold>Improvement in hydrogen storage performance of MgH</bold><bold>2</bold><bold> by vanadium doped with ZIF-8 derived a single-atom catalyst</bold> V-N-C

Herein, the successful preparation of a single-atom catalyst V-N-C using vanadium-doped zeolitic imidazolate framework (ZIF)-8 as a precursor is reported. The experimental results showed that the V-N-C had a good promoting effect on the hydrogen storage performance of MgH2, and the optimal addition amount of V-N-C was 10 wt%. The hydrogenation and dehydrogenation apparent activation energies of 10 wt% V-N-C-catalyzed MgH2 were reduced by 44.9 and 53.5 kJ center dot mol(-1), respectively, compared to those of additive-free MgH2. The 10 wt% V-N-C-catalyzed MgH2 could reabsorb 5.92 wt% of hydrogen in 50 min at 150(degrees)C, with a capacity retention rate of 99.1% after 30 cycles of hydrogen absorption and desorption. Mechanism analysis showed that V-N-C was partially transformed into VN and metallic V when it was milled with MgH2; the in-situ-formed VN and metallic V played an important role in improving the hydrogen storage performance of MgH2. This approach provides a potential solution for obtaining high-performance Mg-based hydrogen storage materials through synergistic interactions between V, N and C.