第一性原理研究Hf对ZrCoH_(3)放氢的影响  

A first-principles study on the effect of Hf on the hydrogen evolution of ZrCoH_(3)

作　　者：曾祥 杨友山 ZENG Xiang;YANG You-Shan(School of Agriculture,Forestry Engineering and Planning,Tongren University,Tongren 554300,China)

机构地区：[1]铜仁学院农林工程与规划学院,铜仁554300

出　　处：《原子与分子物理学报》2024年第4期180-188,共9页Journal of Atomic and Molecular Physics

基　　金：贵州省教育厅青年项目(黔教技[2022]355号)。

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ZrCoH_(3)中.通过第一性原理计算研究了Hf对ZrCoH_(3)放氢的影响.发现用Hf掺杂会使ZrCoH_(3)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Zr_(16)Co_(16)H_(48)> Zr_(16)Co_(16)HfH_(48)> Zr_(16)Co_(15)HfH_(48)> Zr_(15)Co_(16)HfH_(48).理论研究表明在ZrCoH_(3)-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ZrCoH_(3)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Zr_(15)Co_(16)HfH_(48)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.The transition metal element Hf is designed to be added to ZrCoH_(3) by occupying Co atoms,Zr atoms and interstitial sites.The effect of Hf on the hydrogen evolution of ZrCoH_(3) are investigated by first-principles calculations.It is found that substitution with Hf destabilizes ZrCoH_(3),leading to a reductions in the dehydrogenation energy(Ed)and the Co-H average bond length with the order of Zr_(16)Co_(16)H_(48)>Zr_(16)Co_(16)HfH_(48)>Zr_(16)Co_(15)HfH_(48)>Zr_(15)Co_(16)HfH_(48).Theoretical studies show that in the ZrCoH_(3)-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 ZrCoH_(3).Hf atoms preferentially occupy interstitial sites,but this has little effect on the hydrogen dissociation energy.Although the Zr_(15)Co_(16)HfH_(48)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 ZrCoH_(3) 第一性原理计算 放氢性能 过渡金属元素掺杂 

分 类 号：K91[历史地理—人文地理学]