中文摘要：

采用第一原理赝势平面波方法,构建了一个NbH0.6/MgH2相界模型,研究了Nb合金化对MgH2解氢能力与电子结构的影响.结果显示：NbH0.6/MgH2相界的结构稳定性比MgH2相差,表明Nb合金化利于提高MgH2相的解氢能力;Nb对MgH2相解氢能力增强的主要原因在于Nb-H间电子相互作用比Mg-H间强,有利于促进NbH0.6相形核,并且α-Mg在MgH2-Nb体系的NbH0.6/MgH2相界中形核比在MgH2相中容易.

英文摘要：

A NbH0.6/MgH2 interface is designed and constituted in this work. A first-principles plane-wave pseudopotentials method based on Density Functional Theory （DFT） has been used to investigate the Nio-bium alloying effects on the dehydrogenating properties and electronic structure of magnesium hydride,i.e.,MgH2. A low absolute value of the negative heat of formation of NbH0.6/MgH2 interface compared with that of MgH2 indicates Niobium hydrides befit to improve the dehydrogenating properties of MgH2. Based on the analysis of the density of states （DOS） and the total electron density distribution of MgH2 before and after Nb alloying,it was found that the catalysis effect of Nb on dehydrogenating kinetics of MgH2 may attribute to a stronger bonding between Nb and H atoms than that between Mg and H atoms,which leads to nuclea-tion of NbH0.6 phase and the α-Mg at the NbH0.6/MgH2 interface in the MgH2-Nb systems is easier than in pure MgH2 phase.