The First Principles Study of Hydrogen Adsorption on Ni-Decorated LiB (001) Surface**Supported by the National Natural Science Foundation of China under Grant No 60976069, the Science Innovation Training Program under Grant No 2014107191081, and the Science Foundation of Yan'an University under Grant No YD2014-02.

Abstract

The hydrogen adsorption on the one and three Ni-decorated LiB (001) 2×2 surface is investigated by the first principles study. It is demonstrated that Ni atoms are preferentially adsorbed on the top B atom, and form a covalent bond of NiB and an ionic bond of NiLi on the surface. Four H2 molecules can adsorb on the one-Ni-decorated LiB (001) surface, and the average adsorption energy is in a range from −0.35 to −0.58 eV/H2. The charge population analysis shows that the dipole moments on the Ni decorated surface is responsible for the polarization and adsorption of H2. Then, we show that three Ni atoms can be decorated on the LiB (001) 2 × 2 surface, and form a Ni3B nano cluster on the surface, which agrees with experimental results. Three Nidecorated LiB (001) can adsorb up to six H2 molecules, indicating that the Ni-decorated LiB (001) system might be a promising hydrogen storage material.