Stability and bonding mechanism of ternary (Mg, Fe, Ni)H 2 hydrides from first principles calculations
Stability and bonding mechanism of ternary (Mg, Fe, Ni)H 2 hydrides from first principles calculations
复制标题
DOI：
10.1016/j.ijhydene.2008.11.046
复制
发表时间：
2009-02
影响因子：
7.2
通讯作者：
Y. Song;Wang Zhang;R. Yang
中科院分区：
文献类型：
--
作者：
Y. Song;Wang Zhang;R. Yang
采用GGA中的FP-LAPW方法，通过电子结构和总能量计算，研究了三元镁基化合物Mg（Mg，X，Y）H2（X或Y=Fe或Ni）的稳定性和成键机理.根据合金化体系的总能量与纯金属和氢化物的总能量之差，确定了所选合金元素对氢化物稳定性的影响。对超晶胞的整体几何形状和H原子的内部坐标进行了完全弛豫。利用总能量随H原子坐标的变化估算了合金原子与周围H原子的成键相互作用。合金元素Fe和Ni使MgH 2不稳定。这与合金元素和H原子之间的弱键结合改善了MgH 2的脱氢性能。
The stability and bonding mechanism of ternary magnesium based hydrides (Mg, X, Y)H2, X or Y=Fe or Ni, were studied by means of electronic structure and total energy calculations using the FP-LAPW method within the GGA. The influence of the selected alloying elements on the stability of the hydride was determined from the difference between the total energy of the alloyed systems and those of the pure metal and the hydride. Full relaxation was carried out against the overall geometry of the supercell and the internal coordinates of the H atoms. The bonding interactions between the alloying atoms and their surrounding H atoms were estimated using the variation of the total energy against the coordinates of H atoms. The alloying elements, Fe and Ni, destabilised MgH2. This combined with the weak bonds between the alloying elements and H atoms improved the dehydrogenation properties of MgH2.