The electric field effect on the hydrogen storage properties of (MgO)9

(MgO)(9) with a rocksalt structure, a magic number cluster of (MgO)(n), exhibits high stability. In this study, the hydrogen storage properties of (MgO)(9) under an external electric field are explored by DFT calculation. The results reveal that H-2 can be adsorbed on single Mg/O atoms. Because the (MgO)(9) and H-2 are effectively polarized by the external electric field, the adsorption strength of H-2 at certain adsorption sites is substantially enhanced. The adsorption energies of H-2 on three-coordinated Mg/O atoms increase from -0.071/-0.056 eV in the absence of an electric field to -0.186/-0.237 eV under a field intensity of 0.025 a.u. Under the field, (MgO)(9) can adsorb a maximum of 18 H-2 molecules, and the corresponding mass density of hydrogen storage reaches 9.1 wt%. Our results suggest that subjecting the (MgO)(9) to an external electric field is a potential hydrogen storage method. In this paper, the interaction mechanism between H-2 and (MgO)(9) under the external electric field is also investigated through an electronic structure analysis. (C) 2016 Published by Elsevier B.V.