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Catalytic doping plays an important role in enhancing the hydrogen storage performance of MgH₂, while finding an efficient and reversible catalyst remains to be a great challenge in enhancing the de/rehydrogenation properties of MgH₂. Herein, a bidirectional nano-TiH_1.971 catalyst was prepared by a wet chemical ball milling method and its effect on hydrogen storage properties of MgH₂ was studied. The results showed that all the TiH_1.971 nanoparticles were effective in improving the de/rehydrogenation kinetics of MgH₂. The MgH₂ composites doped with TiH_1.971 could desorb 6.5 wt % H₂ in 8 min at 300 &#176;C, while the pure MgH₂ only released 0.3 wt % H₂ in 8 min and 1.5 wt % H₂ even in 50 min. It was found that the smaller the size of the TiH_1.971 particles, the better was the catalytic effect in promoting the performance of MgH₂. Besides, the catalyst concentration also played an important role and the 5 wt %-<i>c</i>-TiH_1.971 modified system was found to have the best hydrogen storage performance. Interestingly, a significant hydrogen absorption amount of 4.60 wt % H₂ was evidenced for the 5 wt %-<i>c</i>-TiH_1.971 doped MgH₂ within 10 min at 125 &#176;C, while MgH₂ absorbed only 4.11 wt% hydrogen within the same time at 250 &#176;C. The XRD results demonstrated that the TiH_1.971 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 MgH₂.