▎ 摘　　要

We have used density functional theory to investigate the electronic properties of two-dimensional porous sheets. The porous C and BN sheets based on graphene and alpha-graphyne are studied. It is found that the porous graphene is an insulator while porous alpha-graphyne has semiconducting properties. By substitution of C atoms by B and N atoms, the band gap becomes larger. The porous graphene-like and porous graphyne-like BN sheets show insulating behaviors. The nonzero band gap of these porous C and BN sheets may provide an opportunity to use them in nanoelectronic devices.