First-principle study of adsorption of hydrogen on Ti-doped Mg(0001) surface

Ab initio density functional theory (DFT) calculations are performed to study the adsorption of H₂ molecules on a Ti-doped Mg(0001) surface. We find that two hydrogen molecules are able to dissociate on top of the Ti atom with very small activation barriers (0.103 and 0.145 eV for the first and second H₂ molecules, respectively). Additionally, a molecular adsorption state of H₂ above the Ti atom is observed for the first time and is attributed to the polarization of the H₂ molecule by the Ti cation. Our results parallel recent findings for H₂ adsorption on Ti-doped carbon nanotubes or fullerenes. They provide new insight into the preliminary stages of hydrogen adsorption onto Ti-incorporated Mg surfaces.