In this paper, the adsorption and storage of hydrogen on calcium-decorated, boron-doped bilayer graphene was investigated using first principles calculation. The calcium-decorated bilayer graphene was investigated and it was shown that the binding energy of H2 molecule adsorbed on the calcium-decorated bilayer graphene is −0.02 eV and the energy does not belong to reversible usage range of −0.2 - −0.6 eV. Substitutional boron doping can improve the adsorption energy of Ca to bilayer graphene with the empty pz orbital of boron atoms. Our calculations show that calcium atoms can be solidly adsorbed on the interlayer (Ca/B/Graphene) and outerlayer (2Ca/B/Graphene and 3Ca/B/Graphene) of B-doped bilayer graphene. Hydrogen molecule binds with Ca/B/Graphene, 2Ca/B/Graphene and 3Ca/B/Graphene system with an energy that belongs to reversible usage range of −0.2 - −0.6 eV. The overlap between Ca 3d and H2σ orbitals just below the Fermi energy demonstrates the charge transfer between the Ca atom and the H atom and the role of hybridization of the 3d orbita of Ca with the σ orbitals of H2 in efficient adsorption of hydrogen molecules. The charge from hydrogen bonding orbital transfers to empty 3d orbitals of the Ca atom, and then from the 3d orbitals of the Ca atom donated to H2σ* antibonding orbital. Hydrogen moleculars can be adsorbed on the interlayer and outerlayer of Ca-decorated B-doped bilayer graphene.
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