Hydrogen separation of porous carbon nanotubes: A density functional theory study

First-principle density functional theory (DFT) is employed to investigate the hydrogen separation performance of porous carbon nanotubes (PCNTs). The calculation results indicate that PCNTs are an excellent material for H2 purification. The reaction path of the gas penetration through PCNTs demonstrates that the diffusion barriers of gas inside or outside the tube are various, 0.413 eV and 0.328 eV, respectively, indicating that the gas located outside the nanotubes is relatively easy to diffuse into the tube. Additionally, PCNTs are more selective to H2 than other gas molecules, up to 1031, superior to porous silicon and porous phosphorene, and making potential material for gas separation.