First Principles DFT Study of Hydrogen Storage on Graphene with La Decoration

Abstract

The properties of hydrogen storage on graphene with La decoration are investigated using a first-principles plane-wave pseudopotential method based on the density functional theory in this paper. The clustering problem of La decorated graphene is considered and B doping can solve it effectively in theory. We obtain the stable geometrical configuration of the modified system and the properties of hydrogen storage are excellent. It can absorb up to 6 H 2 molecules with an average adsorption energy range of – 0.529 to – 0.655 eV/H 2 , which meets the ideal range between the physisorbed and chemisorbed states for hydrogen storage. Furthermore, it is proved that the existence of La atom alters the charge distribution of H 2 molecules and graphene sheet based on the calculation and analysis about the electronic density of states and charge density difference of the modified system. La atom interacts with hydrogen molecules through Kubas interaction. Thereby, it improves the performance of graphene sheet for hydrogen storage. The modified system exhibits the excellent potential to become one of the most suitable candidates for hydrogen storage medium at near ambient conditions with molecule state.