Hydrogen penetration and diffusion on Mg17Al12 (110) surface: A density functional theory investigation

The adsorption, diffusion and penetration of H on the Mg17Al12 (110) surface are investigated systematically by means of the density functional theory calculations. Results indicate that H and H2 prefer to adsorb on the Mg-Mg bridge sites of the Mg17Al12 (110) surface. The lowest barrier energy of molecular hydrogen dissociation on the (110) surface is ∼0.87 eV. The penetration processes of atomic hydrogen incorporation into the Mg17Al12 (110) surface are discussed. It is obtained that the H penetrates from the Mg17Al12 (110) surface into the subsurface with the minimum barrier of ∼0.63 eV, while the hydrogen atom spreads into the deeper Mg17Al12 (110) surface with lower barrier.