Titanium-decorated graphene for high-capacity hydrogen storage studied by density functional simulations.

We present results of density functional theory (DFT) calculations of the adsorption of hydrogen molecules on Ti-decorated graphene. Our results indicate that the binding energies of molecular hydrogen on Ti-decorated graphene can be dramatically enhanced to 0.23-0.60 eV. The hybridization of the Ti 3d orbitals with the H(2) σ and σ* orbitals plays a central role in the enhanced binding. There is also a contribution from the attractive interaction between the surface dipole and the dipole of polarized H(2). It can be expected that Ti-decorated graphene could be considered as a potential high-capacity hydrogen storage medium.