Effect of surface curvature on the hydrogen storage capacity of the Sc-, Ti-, and V-doped graphene surfaces: Theoretical study

Hydrogen (H2) is an excellent energy carrier and can be produced in an environmentally friendly way. The H2 binding performance of different Sc-, Ti-, and V-doped carbon surfaces (i.e., graphenes, circumcoronenes, and circumtrindenes) is investigated using density functional theory. The calculated H2 binding energies are ranging from −12 kJ mol−1 to −22 kJ mol−1 for one H2 molecule per transition metal (TM) atom. Such binding energies are suitable for reversible H2 adsorption and desorption cycle. Obtained results suggest that the curvature of the TM-doped carbon surfaces enhances their H2 binding ability. TM atom in the curved carbon surfaces, representing an active site, is sterically more easily accessible for H2 binding than in the case of the planar metal-doped graphene surfaces. For comparison, the N2 binding ability of the same set of TM-doped carbon surfaces is studied as well.