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化学学报
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化学学报 ›› 2011, Vol. 69 ›› Issue (14): 1715-1720. 上一篇    下一篇

研究论文

LiNH2-X (X＝Mg, Al, Ti, Nb)体系解氢性能的第一原理计算

袁江1,2，周惦武*,1，彭平1，侯德政2   

  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)
    (2湖南张家界航空工业职业技术学院 张家界 427000)
  • 投稿日期:2010-07-07 修回日期:2011-01-10 发布日期:2011-03-21
  • 通讯作者: 袁江 E-mail:57121076@qq.com
  • 基金资助:

    湖南省自然科学基金项目与湖南大学汽车车身先进设计制造国家重点实验室自主研究课题项目;湖南省张家界航空工业职业技术学院创新基金项目

First-Principles Calculation of Dehydrogenating Properties of LiNH2-X (X＝Mg, Al, Ti, Nb) Systems

Yuan Jiang1,2 Zhou Dianwu*,1 Peng Ping1 Hou Dezheng2   

  1. (1 State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha 410082)
    (2 Zhangjiajie Aviation Industry Vocational Technical College, Zhangjiajie 427000)
  • Received:2010-07-07 Revised:2011-01-10 Published:2011-03-21
  • Contact: Jiang Yuan E-mail:57121076@qq.com

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采用基于密度泛函理论的第一原理赝势平面波方法, 计算了LiNH2-X (X＝Mg, Al, Ti, Nb)体系的晶体与电子结构及稳定性能. 负合金形成热与H原子解离能的计算发现: 合金化元素X在LiNH2中少量置换固溶时, 体系结构稳定性发生变化, 合金化增强了体系的解氢能力, 其中Nb提高LiNH2体系解氢效果最好, 理论计算预测合金化提高体系解氢性能与他人结果一致. 电子态密度(DOS)与电子密度分析发现: X (X＝Mg, Al, Ti, Nb)合金化提高LiNH2解氢能力的主要原因是X导致LiNH2体系Fermi能级附近能隙值发生变化以及Li与NH之间的成键作用减弱.

关键词: 赝势平面波, LiNH2, 合金形成热, 电子结构

Crystal, electronic structure and stability of LiNH2-X (X＝Mg, Al, Ti, Nb) system have been determined from first-principles calculation based on the density functional theory. The calculated negative heat of formation and dissociation energy of H atom show that when a little X dissolve into LiNH2 in a small amount of replacement solution, there are some changes on structural stability, alloying elements benefit to improve the dehydrogenating properties of the system and Nb was considered as the best element. Some results from theoretical calculation which alloying system can improve the dehydrogenation properties of LiNH2 hydride are in agreement well with other ones. After comparing the densities of states (DOS) and the charge distribution, it is found that the catalysis effect of X (X＝Mg, Al, Ti, Nb) on dehydrogenating kinetics of LiNH2 may attribute to the changes of energy gap near the Fermi level and the weakened bonding between Li and NH.

Key words: plane-wave pseudopotential theory, LiNH2, heat of formation, electronic structure

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