第一性原理研究Hf对ZrCoH3放氢的影响
A first-principles study on the effect of Hf on the hydrogen evolution of ZrCoH3
曾祥 1杨友山1
作者信息
- 1. 铜仁学院 农林工程与规划学院,铜仁 554300
- 折叠
摘要
过渡金属元素Hf被设计成通过占据Co原子、Zr原子和间隙位点来添加到ZrCoH3 中.通过第一性原理计算研究了Hf对ZrCoH3放氢的影响.发现用Hf掺杂会使ZrCoH3 不稳定,导致氢离解能(Ed)、Co-H平均单位键长的键序(SBOCo-H)降低,顺序为Zr16Co16H48>Zr16Co16HfH48>Zr16Co15HfH48>Zr15Co16HfH48.理论研究表明在ZrCoH3-Hf体系中,较弱的Co-H共价键相互作用、金属特性和Hf-H键的形成都有利于提高ZrCoH3的放氢能力.Hf原子优先占据间隙位,但这对氢离解能影响很小,氢离解能与位置能之间存在悖论关系.尽管Zr15Co16HfH48化合物具有低的氢离解能,表现出良好的放氢性能,但在实际应用Hf占据Zr位时需要消耗过高的能量成本.
Abstract
The transition metal element Hf is designed to be added to ZrCoH3 by occupying Co atoms,Zr atoms and interstitial sites.The effect of Hf on the hydrogen evolution of ZrCoH3 are investigated by first-principles calculations.It is found that substitution with Hf destabilizes ZrCoH3,leading to a reductions in the dehydrogen-ation energy(Ed)and the Co-H average bond length with the order of Zr16Co16H48>Zr16Co16HfH48>Zr16Co15HfH48>Zr15Co16HfH48.Theoretical studies show that in the ZrCoH3-Hf system,the weaker Co-H covalent bond interaction,metallic properties and the formation of Hf-H bonds are all beneficial to improve the hydrogen release capacity of ZrCoH3.Hf atoms preferentially occupy interstitial sites,but this has little effect on the hydro-gen dissociation energy.Although the Zr15Co16HfH48 compound has low hydrogen dissociation energy and exhibits good hydrogen desorption performance,it needs to consume too high energy cost when Hf occupies Zr site in practical application.
关键词
储氢/ZrCoH3/第一性原理计算/放氢性能/过渡金属元素掺杂Key words
Hydrogen storage/ZrCoH3/First-principles calculations/Dehydrogenation performance/Transition metal element doping引用本文复制引用
基金项目
贵州省教育厅青年项目(黔教技[2022]355号)
出版年
2024
国家科技期刊平台
NSTL
万方数据