Enhancement effect of Ce hydride on hydrogen storage performance of Mg(NH2)2-2LiH
Enhancement effect of Ce hydride on hydrogen storage performance of Mg(NH2)2-2LiH
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DOI：
10.1016/j.jallcom.2023.172247
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发表时间：
2023-09
影响因子：
6.2
通讯作者：
Chen Jin;Haoyuan Zheng;Li Wang;Haizhen Liu;Xinhua Wang;Mi Yan
中科院分区：
文献类型：
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作者：
Chen Jin;Haoyuan Zheng;Li Wang;Haizhen Liu;Xinhua Wang;Mi Yan
由于Mg（NH2）2 - 2LiH体系具有较高的储氢容量和125 ℃左右的温和放氢温度，可作为新一代车载储氢材料，但吸放氢动力学仍存在很大障碍。本文首次采用稀土氢化物CeH_（2.51）作为改性催化剂，以提高其储氢性能。实验结果表明，与纯Mg（NH2）2 - 2LiH相比，CeH2. 51的加入能显著改善Mg（NH2）2 - 2LiH的吸放氢动力学和循环性能。CeH_（2.51）掺杂量为7.5wt%时，样品的综合性能最好。初始放氢温度和吸氢温度分别降至110 ° C和60 ° C，放氢活化能从120.0 kJ/mol降至102.5 kJ/mol，经10次吸放氢循环后，储氢量几乎没有衰减。此外，通过各种表征也阐明了CeH2.51改善Mg（NH2）2 - 2LiH储氢性能的机制。
Because Mg(NH2)2-2LiH system has a high hydrogen storage capacity and a mild hydrogen release temperature around 125 °C, it can be used as a new generation of on-board hydrogen storage material, but the hydrogen absorption and release kinetics still have great obstacles. In this paper, CeH2.51, a rare earth hydride, was used as a modified catalyst to improve its hydrogen storage performance for the first time. The experimental results showed that the addition of CeH2.51can significantly improve the hydrogen absorption/desorption kinetics and cycle performance compared with that of the pristine sample Mg(NH2)2-2LiH. And the sample doped with 7.5 wt% CeH2.51shows the best comprehensive performance. The initial hydrogen release and absorption temperatures drops to 110 °C and 60 °C, respectively, and the activation energy of hydrogen release decreased from 120.0 kJ/mol to 102.5 kJ/mol, the hydrogen storage capacity of has almost no decay after 10 absorption/desorption cycles. In addition, the mechanism of CeH2.51improving the hydrogen storage performance of Mg(NH2)2-2LiH was also clarified by various characterizations.