Theoretical investigation of calcium-decorated β12 boron sheet for hydrogen storage

Abstract

From first-principles calculations based on density functional theory, we find that the recently synthesized β12 boron sheet is a perfect candidate for calcium-decoration and hydrogen storage application. In contrast to graphene where defects are required to capture Ca, the naturally formed hexagonal hollow ring in β12 boron sheet provides the ideal site for Ca adsorption, and up to 6H2 molecules for each Ca atom can be captured with a desirable binding energy of ∼0.2 eV/H2. The gravimetric hydrogen density for Ca decorated boron sheet can reach up to 8.92 wt%. From the electronic analysis, it is found that both the orbital hybridizations and polarization mechanism play significant roles in H2 adsorption and storage.