%A DU Xiao-Ming, LI Wu-Hui, HUANG Yong, WU Er-Dong
%T First-Principles Calculation of the Crystal Structure and Stabilization of Mg-Ti-H System
%0 Journal Article
%D 2011
%J Acta Phys. -Chim. Sin.
%R 10.3866/PKU.WHXB20112793
%P 2793-2798
%V 27
%N 12
%U {http://www.whxb.pku.edu.cn/CN/abstract/article_27768.shtml}
%8 2011-11-25
%X First-principles calculations were performed to determine the equilibrium crystal structures, energetic properties, and stability of Mg_{x}Ti_{(1-x)}H_{2} (*x*=0.25, 0.5, 0.75, 0.875) systems containing different amounts of titanium using the pseudopotential plane-wave method based on density functional theory. The calculation results show that the hydrogen atoms in the Mg_{x}Ti_{(1-x)}H_{2} hydrides roughly occupy the tetrahedral interstitial sites. The calculated H―Ti distances are less than the H―Mg distances. This indicates that Ti has a more notable affinity for hydrogen than Mg. The bonding strength of H―Mg is weaker when the Ti atom attracts surrounding hydrogen atoms. The stabilization and dehydrogenation temperatures of the hydrides Mg_{x}Ti_{(1-x)}H_{2} are lower than those of MgH_{2} with an increasing Ti content. This indicates that titanium can reduce the decomposition temperature of the Mg_{x}Ti_{(1-x)}H_{2} hydrides and play a significant catalytic role in improving the dehydrogenation dynamic properties of the Mg_{x}Ti_{(1-x)}H_{2} hydrides.