Modelling carbyne C12-ring calcium decorated for hydrogen storage

Abstract

We computationally investigate the hydrogen storage properties of C12 carbyne structure decorated with one and up to six calcium (Ca) atoms adsorbed to outer surface. The calculations are carried out by density functional theory DFT with the generalized gradient approximation PW91 (Perdew and Wang) as implemented in the modeling and simulation Materials Studio software. Dmol3 is used to calculate, total energies, charge density HOMO-LUMO and Mulliken population analysis. Based on these results, up to six H2 molecules per Ca atom can be physisorbed with an average binding energy of 0.1272 eV per H2 molecule. The study is extended to a system with six calcium atoms, which can adsorb up to 36 H2 molecules. This leads to 15.87 weight percentage (wt %) for the gravimetric hydrogen storage capacity. According to these results, the calcium-coated carbyne C12 structure is a good candidate for hydrogen storage with application to fuel cells.