The hydrogen storage performance and catalytic mechanism of the MgH2-MoS2 composite

In this work, we synthesized MoS2 catalyst via one-step hydrothermal method, and systematically investigated the catalytic effect of MoS2 on the hydrogen storage properties of MgH2. The MgH2-5MoS2 composite milled for 5 h starts to release hydrogen at 259 °C. Furthermore, it can desorb 4.0 wt.% hydrogen within 20 min at 280 °C, and absorb 4.5 wt.% hydrogen within 5 min at 200 °C. Mo and MoS2 coexisted in the ball milled sample, whereas only Mo was kept in the sample after dehydrogenation and rehydrogenation, which greatly weakens the Mg-H bonds and facilitates the dissociation of MgH2 on the surface of Mo (110). The comparative study show that the formed MgS has no catalytic effect for MgH2. We believed that the evolution and the catalytic mechanism of MoS2 will provide the theoretical guidance for the application of metal sulfide in hydrogen storage materials.