Nitrogen-Modified Graphdiyne as a Promising Membrane for Helium Separation: First-Principles and Molecular Dynamics Simulations

Abstract

The He separation performance of the N-modified graphdiyne monolayer (N-GDY) was studied by using both the first-principles density functional theory (DFT) and molecular dynamics (MD) simulations. The high cohesive energy of 7.24 eV/atom confirmed the strong stability of N-GDY for a gas separation membrane. Based on the calculations, the N-GDY membrane was found to exhibit extremely high He permeance (4.8 ×10-3 mol/m2·s·Pa at 100 K) and selectivities of He/H2O, He/Ar, He/N2, He/CO, He/CO2, and He/CH4 (102~1012 at 300 K). Therefore, N-GDY should be a good candidate for He separation from natural gas.