电场中MgO分子吸附H_2的理论研究

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.

Theoretical Study of H2 Adsorption on MgO Molecule under External Electric Field

The study on the interaction between H2 and MgO molecule under external electric field is the basis for exploring the properties of hydrogen storage of MgO-based materials. The adsorption properties of H2 on an MgO molecule under external electric field are studied at the level of B3LYP/6-31G**. The results show that the external electric field can efficiently enhance the adsorption energy of single H2 on the Mg/O ions from -0.021/-0.099eV without electric field to -0.037/-0.139 eV with the field intensity of 0.005a.u, respectively. The electric field effect on O ion is more significant than that of Mg ion. Under the electric field, an MgO molecule can adsorb ten H2 molecules at most, and the corresponding mass density of hydrogen storage reaches to 33wt%. Our results suggest that the MgO-based materials adsorbed H2 under external electric field is a potential method for hydrogen storage. The interaction between MgO molecule and H2 under electric field is also discussed by the analysis of electronic structure.