The effect of layer number on the gas permeation through nanopores within few-layer graphene.

Few-layer graphene has been widely regarded as an efficient filter for gas separation, but the effect of the layer number on the gas permeation process is still unclear. To explore the layer number effect, we perform molecular dynamics simulations to investigate the gas permeation through a nanopore within the few-layer graphene. Our numerical simulations show that the permeation constant decreases with increasing layer number, which is analyzed based on the macroscopic Kennard empirical model. The macroscopic model is in good agreement with the numerical result in the limit of large layer number, but there are obvious deviations for the medium layer number. We generalize the macroscopic model by considering the nanoscale effect from the surface morphology of the nanoscale pore, which can well describe the layer number dependence for the gas permeation constant in the full range. These results provide valuable information for the application of few-layer graphene in the gas permeation field.