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化学学报
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化学学报 ›› 2010, Vol. 68 ›› Issue (10): 955-960. 上一篇    下一篇

研究论文

MgH2-Nb体系解氢能力与电子结构的第一原理计算

周惦武*,1，张健2，徐少华3，彭平3，刘金水3   

  1. (1湖南大学汽车车身先进设计制造国家重点实验室 长沙 410082)
    (b长沙理工大学汽车与机械工程学院 长沙 410114)
    (c湖南大学材料科学与工程学院 长沙 410082)
  • 投稿日期:2009-10-26 修回日期:2009-12-24 发布日期:2010-01-05
  • 通讯作者: 周惦武 E-mail:ZDWe_mail@yahoo.com.cn

First-principles Calculation of Electronic Structure and Dehydrogenating Properties of MgH2-Nb Systems

Zhou Dianwu*,1 Zhang Jian2 Xu Shaohua3 Peng Ping3 Liu Jinshui3   

  1. (1 State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha 410082)
    (2 School of Vehicle and Mechanical Engineering, Changsha University of Science & Technology, Changsha 410114)
    (3 School of Materials Science and Engineering, Hunan University, Changsha 410082)
  • Received:2009-10-26 Revised:2009-12-24 Published:2010-01-05

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采用第一原理赝势平面波方法, 构建了一个NbH0.6/MgH2相界模型, 研究了Nb合金化对MgH2解氢能力与电子结构的影响. 结果显示: NbH0.6/MgH2相界的结构稳定性比MgH2相差, 表明Nb合金化利于提高MgH2相的解氢能力; Nb对MgH2相解氢能力增强的主要原因在于Nb-H间电子相互作用比Mg-H间强, 有利于促进NbH0.6相形核, 并且α-Mg在MgH2-Nb体系的NbH0.6/MgH2相界中形核比在MgH2相中容易.

关键词: MgH2, 第一原理计算, 解氢能力, 电子结构

A NbH0.6/MgH2 interface is designed and constituted in this work. A first-principles plane-wave pseudopotentials method based on Density Functional Theory (DFT) has been used to investigate the Niobium alloying effects on the dehydrogenating properties and electronic structure of magnesium hydride, i.e., MgH2. A low absolute value of the negative heat of formation of NbH0.6/MgH2 interface compared with that of MgH2 indicates Niobium hydrides befit to improve the dehydrogenating properties of MgH2. Based on the analysis of the density of states (DOS) and the total electron density distribution of MgH2 before and after Nb alloying, it was found that the catalysis effect of Nb on dehydrogenating kinetics of MgH2 may attribute to a stronger bonding between Nb and H atoms than that between Mg and H atoms, which leads to nucleation of NbH0.6 phase and the α-Mg at the NbH0.6/MgH2 interface in the MgH2-Nb systems is easier than in pure MgH2 phase.

Key words: MgH2, first-principles calculation, dehydrogenating properties, electronic structure