Abstract Catalytic doping is an important strategy for enhancing the hydrogen storage performance of magnesium hydride. Hence, LaNi4.5Mn0.5 submicro-particles were successfully prepared via a facile wet chemical ball milling method. To further study the catalytic performance, various amount of as-received LaNi4.5Mn0.5 were introduced to MgH2 and the submicro-LaNi4.5Mn0.5 showed best catalytic effect on MgH2. Specifically, experimental results showed that LaNi4.5Mn0.5 submicro-particles modified MgH2 started to release hydrogen at 175 °C, about 150 °C lower than that of additive-free MgH2. At 300 °C, the composite could desorb 6.6 wt% H2 within 6 min. Moreover, the fully dehydrogenated sample could take up hydrogen at room temperature and 4.1 wt% H2 was charged within 10 min at 150 °C. The apparent activation energy of MgH2 for hydrogenation after doping submicro-LaNi4.5Mn0.5 was greatly reduced from 72.50 ± 2.70 to 16.63 ± 1.40 kJ/mol. Furthermore, a hydrogen capacity of 6.1 wt% was maintained after 10 cycles. The synergetic effects between the in-situ formed Mg2Ni/Mg2NiH4, Mn and LaH3 may contribute to the promoted hydrogen dissociation and diffusion along the Mg/MgH2 interface, thus reducing the energy barrier and enhancing the hydrogen storage performance of MgH2.

中文翻译：

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简易合成的 LaNi4.5Mn0.5 亚微粒对 MgH2 储氢性能的优异催化作用

摘要 催化掺杂是提高氢化镁储氢性能的重要策略。因此，LaNi4.5Mn0.5 亚微米颗粒通过简便的湿化学球磨法成功制备。为了进一步研究催化性能，将不同量的LaNi4.5Mn0.5引入到MgH2中，亚微LaNi4.5Mn0.5对MgH2的催化效果最好。具体而言，实验结果表明，LaNi4.5Mn0.5 亚微粒修饰的 MgH2 在 175 °C 开始释放氢，比无添加剂的 MgH2 低约 150 °C。在 300 °C 时，复合材料可以在 6 分钟内解吸 6.6 wt% 的 H2。此外，完全脱氢的样品在室温下可以吸收氢气，并且在 150°C 下在 10 分钟内加入 4.1 wt% 的氢气。掺杂亚微LaNi4.5Mn0.5后，MgH2加氢表观活化能从72.50±2.70大大降低到16.63±1.40kJ/mol。此外，在 10 次循环后仍保持 6.1 wt% 的氢容量。原位形成的 Mg2Ni/Mg2NiH4、Mn 和 LaH3 之间的协同作用可能有助于促进氢沿 Mg/MgH2 界面的解离和扩散，从而降低能垒并提高 MgH2 的储氢性能。