What's the appropriate precondition for ammine metallic borohydrides to generate pure hydrogen?
What's the appropriate precondition for ammine metallic borohydrides to generate pure hydrogen?
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DOI：
10.1016/j.ijhydene.2017.05.013
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发表时间：
2017-06
影响因子：
7.2
通讯作者：
Kun Wang;Qian Liu;Xuewei Lang;Kai Tang;Jianguo Zhang
中科院分区：
文献类型：
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作者：
Kun Wang;Qian Liu;Xuewei Lang;Kai Tang;Jianguo Zhang
在储氢材料领域，多阳离子化合物往往比单金属化合物表现出更好的可控性。与氨基金属硼氢化物(AMB)一样，锂和镁具有相似的化学性质，但在防止氢释放过程中的杂质方面表现出不同的外观。我们在前人研究的基础上，用CAR-Parrinello分子动力学方法对LiMg(BH4)3(NH3)2(AMLB)和LiBH4NH3(ALB)的脱氢途径进行了研究。有趣的是，由于相应的混合金属的影响，氢的纯度从ALB到AMGB再到AMLB逐渐提高。此外，AMLB中的两种金属密切合作，控制[NH3]和[BH4]基团的运动，这两个基团几乎抑制了所有的杂质，并在分解过程中表现出增强的性能。从我们的结果来看，脱氢性能的改善应该取决于中心金属的大极化(S)。此外，氢的纯度取决于自由氢离子的数量。
Multiple-cation compounds always show more desirable controllability than that of mono-metallic compounds in the field of the hydrogen-storage materials. As in the ammine metallic borohydrides (AMB), Li and Mg appears similar chemical properties, but they show different appearances in preventing the impurities in the hydrogen releasing process. We applied Car–Parrinello molecular dynamic (CPMD) method to investigate the dehydrogenation pathway for LiMg(BH4)3(NH3)2(AMLB) on the basis of our previous study of Mg(BH4)2(NH3)2(AMgB) and LiBH4NH3(ALB). Interestingly, the purity of hydrogen gradually improves from ALB to AMgB to AMLB caused by the effects of the corresponding mixed metals. Furthermore, the two metals in AMLB are in close cooperation to control the motion of [NH3] and [BH4] groups, which suppress almost all the impurities and show enhanced properties in the decomposition. From our results, the improved dehydrogenation performance should depend on the large polarization of the centre metal(s). Furthermore, the purity of the hydrogen is depending on the quantities of the free hydrogen ions.