摘要
采用基于密度泛函理论的第一性原理赝势平面波方法,计算了Nb合金化前后Mg2Ni及其氢化物的能量与电子结构。合金生成焓分析表明:当Nb原子占据Mg(6i)位置时,Mg2Ni的结构最为稳定;进一步对其氢化物进行分析,发现Nb合金化降低了氢化物的稳定性,氢原子的解离能明显减小,表明体系的解氢能力得到增强。电子结构分析表明:Mg2Ni H4中存在着较强的Ni-H键的作用,而Mg-H键作用相对较弱,由于Nb与H的作用大于Mg与H的作用,而导致Ni-H键的作用减弱,这可能是Nb合金化后氢化物稳定性降低的一个原因。
The energies and electronic structures of Nb alloying Mg2 Ni and the corresponding hydrides were investigated by the first-principles plane-wave pseudopotential method based on the density functional theory. The results of the formation enthalpy show that when Nb atom occupies the Mg（6i） lattice sites, the structure of Mg2 Ni has the highest structure stability. The further analysis of the hydrides shows that Nb alloying significantly decreases the stability of the hydrides and the dissociated energies of H atoms, indicating that Nb alloying benefits the improvement of the dehydrogenating properties of Mg2 Ni hydrides. Analysis of the electronic structures suggests that Ni-H bond is stronger than the Mg-H bond in Mg2 Ni H4 phase. The Ni-H bond is weakened because the interaction between Nb and H is stronger than the interaction between Mg and H. This may be one of the reasons of decreasing structure stability of the hydrides.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2015年第2期386-390,共5页
Rare Metal Materials and Engineering
基金
教育部高校博士点基金(20101415110003)
太原市科技计划项目(110153)
山西省高校科技研究开发项目(2010118)
