The First Principles Study of Hydrogen Adsorption on Ni-Decorated LiB (001) Surface

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 Ni-decorated LiB (001) can adsorb up to six H₂ molecules, indicating that the Ni-decorated LiB (001) system might be a promising hydrogen storage material.