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

Abstract

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 10⁵ 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.