Catalytic Effect of Facile Synthesized TiH Nanoparticles on the Hydrogen Storage Properties of MgH.

Catalytic doping plays an important role in enhancing the hydrogen storage performance of MgH, while finding an efficient and reversible catalyst remains to be a great challenge in enhancing the de/rehydrogenation properties of MgH. Herein, a bidirectional nano-TiH catalyst was prepared by a wet chemical ball milling method and its effect on hydrogen storage properties of MgH was studied. The results showed that all the TiH nanoparticles were effective in improving the de/rehydrogenation kinetics of MgH. The MgH composites doped with TiH could desorb 6.5 wt % H in 8 min at 300 °C, while the pure MgH only released 0.3 wt % H in 8 min and 1.5 wt % H even in 50 min. It was found that the smaller the size of the TiH particles, the better was the catalytic effect in promoting the performance of MgH. Besides, the catalyst concentration also played an important role and the 5 wt %--TiH modified system was found to have the best hydrogen storage performance. Interestingly, a significant hydrogen absorption amount of 4.60 wt % H was evidenced for the 5 wt %--TiH doped MgH within 10 min at 125 °C, while MgH absorbed only 4.11 wt% hydrogen within the same time at 250 °C. The XRD results demonstrated that the TiH remained stable in cycling and could serve as an active site for hydrogen transportation, which contributed to the significant improvement of the hydrogen storage properties of MgH.