电场中MgO分子吸附H_2的理论研究

Theoretical study of H_2 adsorption on MgO molecule under external electric field

研究电场中MgO分子与H_2的相互作用是探索MgO材料储氢性能的基础.在B3LYP/6-31G**水平上研究了电场中H2在MgO分子上的吸附行为.结果给出电场中单个H_2在Mg/O上的吸附能由无电场时-0.021/-0.099eV提高到场强为0.005a.u.时的-0.037/-0.139eV.H2吸附在O离子上时,电场效应更显著.电场中MgO分子最多能吸附10个H_2,相应的质量密度达33wt%.表明电场诱导MgO材料吸附H_2是一种具有潜力的储氢方法.通过电子结构分析讨论了电场中MgO分子储氢的机理.

The study on the interaction between H_2 and Mg O molecule under external electric field is the basis for exploring the properties of hydrogen storage of Mg O- based materials. The adsorption properties of H_2 on a Mg O molecule under external electric field are studied at the level of B3 LYP /6- 31G＊＊. The results show that the external electric field can efficiently enhance the adsorption energy of single H_2 on the Mg / O ions from- 0. 021 /- 0. 099 e V without electric field to- 0. 037 /- 0. 139 e V with the field intensity of 0. 005 a. u.,respectively. The electric field effect on O ion is more significant than that of Mg ion. Under the electric field,a Mg O molecule can adsorb ten H_2 molecules at most,and the corresponding mass density of hydrogen storage reaches to 33wt%. Our results suggest that the electric field- induced adsorption of H_2 on the Mg O- based materials is a potential method for hydrogen storage. The interaction between Mg O molecule and H_2 under electric field is also discussed by the analysis of electronic structure.