Ni catalytic effects for the enhanced hydrogenation properties of Mg17Al12(1 1 0) surface

We present hydrogen adsorption properties enhancement for the Ni-adsorbed and -substituted Mg17Al12 (1 1 0) surfaces. Results show that using density functional theory methods, the effects of Ni addition on the hydrogen storage properties of Mg17Al12 alloy are revealed. Compared with the clean Mg17Al12 (1 1 0) surfaces, hydrogen atoms and molecules adsorption on the Mg17Al12(1 1 0)/Ni, Mg16NiAl12(1 1 0), and Mg15Ni2Al12(1 1 0) surfaces are significantly improved. In addition, the effects of Ni are also observed in the processes of hydrogen dissociation (diffusion) on (in) the Ni-containing systems. Calculations indicate that molecular hydrogen dissociation on the Mg17Al12 (1 1 0)/Ni surface is spontaneous. Moreover, the barrier energies of H incorporation from the Ni-containing surfaces into the subsurfaces are much lower than that case of the pure (1 1 0) surfaces. Ni plays an active role in improving hydrogenation properties and facilitating hydrogen transportation.