The hydrogen storage properties of the Ti decorated benzene-Ti-graphene sandwich-type structures

The binding energy(Eb) for the Ti atom to (6x6) armchair graphitic sheet and (4x7) zigzag graphitic sheet are a little smaller than the experimental cohesive energy of bulk Ti(4.85 eV/atom). Therefore, when more Ti atoms are adsorbed on the structure, the clustering of Ti atoms perhaps appear, which will hander the further hydrogen storage. However, the Eb for the Ti atom to the zigzag and armchair substrate in the two sandwich-type structures increase to 8.27 eV and 8.62 eV respectively, not only are much higher than the Eb of Ti-graphene structure, but also are nearly double of the experimental cohesive energy of bulk Ti(4.85 eV/atom). Therefore, the problem of metal aggregative to form the cluster is expected to be overcome in these two sandwich-type structures, and the materials will be stable for hydrogen storage. Moreover, The desorption temperature TD for two hydrogen molecules adsorbed benzene-Ti-graphene(BTG) structures are at the room temperature, suggesting that the hydrogen release at near-ambient temperature may be feasible.250