Exploration of nanoporous graphene membranes for the separation of N2 from CO2: a multi-scale computational study

Density functional theory (DFT) calculations and molecular dynamic (MD) simulations were performed to investigate the capability of graphene membranes with H-passivated nanopores for the separation of N2/CO2 gas mixtures. We found that the graphene membrane, H-pore-13, with its appropriate pore size of 4.06 Å, can efficiently separate N2 from CO2. Different from the previously reported preferential permeation of CO2 over N2 resulting from size sieving, H-pore-13 can exhibit high N2 selectivity over CO2 with a N2 permeance of 10(5) GPU (gas permeation unit), and no CO2 was found to pass through the pore. It was further revealed that electrostatic sieving plays a cruical role in hindering the passage of CO2 molecules through H-pore-13.