A quantum chemical study on magnesium(Mg)/magnesium-hydrogen(Mg-H) nanowires

We report on the quantum chemical study of magnesium(Mg)/magnesium-hydrogen(Mg-H) nanowires with the diameter of ∼1 nm. The Mg-H nanowire, which is formed by loading H atoms on the surface of Mg nanowire, exhibits the same hydrogen-storage capacity as that of bulk stoichiometric MgH2 (7.6 wt%) but a significant low desorption enthalpy of 37.55 kJ/mol H2, which corresponds to an ambient-close desorption temperature of 287 K. The subsequent investigations of electronic structure and stability of the Mg-H nanowires reveal that the strength of Mg-H interaction can be further adjusted by considering the H-content and size effects. These results show that the Mg/Mg-H nanowires with the diameter of ∼1 nm are promising for hydrogen storage due to the proper hydride thermodynamics.