Electronic properties of porous graphene and its hydrogen storage potentials

Abstract

First principles calculation based on density functional theory has been applied to systematically study the electronic structure, especially band gap of recently synthesized periodic porous structure, graphene nanomesh, as well as its analogous system BN nanomesh. These porous structures possess various band gaps due to two parameters: neck length and width. The modulation of these parameters can be achieved through different etching templates in experiments. Two mechanisms, plane and nanoribbon, are proposed to understand the band gap variation with respect to neck length and width, qualitatively. We also examine electronic frontier states around Fermi level. Especially, armchair necked BN nanomesh has separated highest occupied and lowest unoccupied states in real space, which also makes it be reactive at different site. The hydrogen storage potentials based on transition metal atoms such as Sc trapped in anionic decorated pores are also been explored. No clustering problem is found and one Sc can adsorb four H2 molecules with binding energy per H2 of 0.13 eV.