In order to further study the hydrogen storage mechanism of Mg-based hydrogen storage materials, Mg90Ce5Y5 alloy was used as the basis, and three kinds of heavy rare earth oxides were doped into the alloy by ball milling technology. The microstructure and hydrogen storage properties were characterized by XRD, SEM, TEM and PCI. The results show that the hydrogen absorption rate and discharge rate of modified Mg90Ce5Y5 alloy are significantly increased, and the performance is Er2O3 > Dy2O3 > Yb2O3. The hydrogen storage capacity of Er2O3 catalyzed samples is 5.02 wt%, which is higher than 4.82 wt% and 4.80 wt% of Dy2O3 and Yb2O3 catalyzed samples. The hydrogen absorption saturation rate of the sample catalyzed by Er2O3 for 2 min is ∼90 %, the complete release of hydrogen only takes 50 min at 573 K, and the dehydrogenation activation energy is 76.9 kJ/mol. The hydrogen absorption and emission rate is fast, and the dehydrogenation activation energy is slightly lower than that of the other two catalysts. In the process of hydrogen absorption and desorption, the three catalysts exhibit different phase transitions, namely DyH2↔DyH3, ErH2↔ErH3 and irreversible YbH2. DyH2↔DyH3, ErH2↔ErH3 phase transitions have the "hydrogen pump" effect, which can effectively improve the hydrogen absorption and desorption kinetic rate of Mg90Ce5Y5 alloy. Some nano-rare earth compounds and phase transformation significantly improve the kinetic properties of the alloy. However, the enthalpy change of all three catalytic alloys is around 76 kJ/mol H2, which is considered only a slight improvement in thermodynamic properties.

中文翻译：

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RE2O3改性Re-Mg基合金的显微组织及储氢性能研究 （RE = Dy， Er， Yb）


为进一步研究Mg基储氢材料的储氢机理，以Mg90Ce5Y5合金为基础，通过球磨技术将三种重稀土氧化物掺杂到合金中。通过 XRD、SEM、TEM 和 PCI 对微观结构和储氢性能进行了表征。结果表明，改性Mg90Ce5Y5合金的吸氢速率和放电速率显著提高，性能为Er2O3 > Dy2O3 > Yb2O3。Er2O3 催化样品的储氢能力为 5.02 wt%，高于 Dy2O3 和 Yb2O3 催化样品的 4.82 wt% 和 4.80 wt%。Er2O3 催化 2 min 的样品吸氢饱和速率为 ∼90 %，在 573 K 下氢的完全释放仅需 50 min，脱氢活化能为 76.9 kJ/mol。氢气吸收和排放速度快，脱氢活化能略低于其他两种催化剂。在氢气吸收和解吸过程中，三种催化剂表现出不同的相变，即 DyH2↔DyH3、ErH2↔ErH3 和不可逆 YbH2。DyH2↔DyH3、ErH2↔ErH3 相变具有“氢泵”效应，可有效提高 Mg90Ce5Y5 合金的吸氢和解吸动力学速率。一些纳米稀土化合物和相变显着改善了合金的动力学性能。然而，所有三种催化合金的焓变都在 76 kJ/mol H2 左右，这被认为只是热力学性能的轻微改进。