▎ 摘　　要

Nanoporous graphene is being regarded as a promising candidate for reliable gas separation and purification applications. In the present research, the permeation barrier, selectivity and all thermodynamic functions for passing of four different molecules including CH4, H2S, N-2 and CO2 gases on four types of porous graphene which is doped by two, three and six nitrogen atoms using quantum mechanical modelling, based on the density functional theory, B97D, and cc-pVTZ basis set have been evaluated. We find that the permeation barrier of all studied gases especially carbon dioxide decreased by considering the functionalized porous graphene by two, three and six nitrogens-doped, respectively. The results of our study propose using a porous graphene sheet as highly efficient and highly selective membranes for gas separations.