Hydrogen interlayer adsorption on Ti-functionalized Mg(0001). A density functional theory research

Hydrogen storage is one of the growing topics in recent years. In the present manuscript, hydrogen adsorption on the pristine and titanium-functionalized Mg(0001) surface is studied applying density functional theory. Ti adsorption between the external layers is more stable than on the surface. Increasing slightly the Titanium coverage, increases the binding energy per Ti atom. Molecular hydrogen interaction with the clean Mg surface is weak (adsorption energy of ≈ -0.03 eV/H 2 ) whereas dissociative adsorption is not stable. However, hydrogen dissociative adsorption between the external layers near adsorbed Titanium atoms, is stable. This indicates the adsorbed Ti atoms enhance the hydrogen storage of the Mg surface. Hydrogen adsorption is less stable as its coverage increases (in the hydrogen low coverage regime). Charge density analysis and activation energy calculations are performed. Titanium-functionalized Mg(0001) surface seems to be a promising material in the topic hydrogen storage. • The interaction of titanium atoms with the Mg(0001) surface is strong. • The most stable adsorption of Ti atoms is between the external Mg layers. • Ti d xy and d yz are shifted upon adsorption. • The interaction of molecular hydrogen with the clean Mg surface is very weak and dissociative adsorption is not stable. • Hydrogen dissociative adsorption between the Mg surface external layers near titanium atoms, is stable.