Bilayer Heterostructure of Boron Nitride and Graphene for Hydrogen Storage: A First-Principles Study

We report the hydrogen storage properties of the bilayer h-BN/Gr heterostructure using the density functional theory calculations incorporating DFT-D2 and D3 dispersion corrections. The hydrogen molecules are adsorbed in between the two monolayers and on top of the graphene layer with a maximum gravimetric density of 5.83 wt %. The average adsorption energy per hydrogen molecules (−0.23 eV/H2) is in line with the USDOE benchmark. DFT-D3 shows an enhancement in the adsorption energy by 0.01–0.02 eV. The potentiality of the h-BN/Gr heterostructure for hydrogen storage material can be ascertained from the fact that the material can adsorb hydrogen molecules at all available sites within the binding energy limit (−0.15 to −0.60 eV/H2) without external factors such as metal decorations, electric field, or strain. The hydrogen adsorption on h-BN/Gr is highly modulated by weak van der Waals and electrostatic interactions.