Graphenylene-1 Membrane: An Excellent Candidate for Hydrogen Purification and Helium Separation

In this study, we use the density functional theory (DFT) calculations and the molecular dynamics (MD) simulations to investigate the performance of graphenylene--1 membrane for hydrogen ($H_2$) purification and helium ($He$) separation. The stability of this membrane is confirmed by calculating its cohesive energy. Our results show that a surmountable energy barrier for $H_2$ (0.384 eV) and $He$ (0.178 eV) molecules passing through graphenylene-1 membrane. At room temperature, the selectivity of $H_2$/$CO_2$, $H_2$/$N_2$, $H_2$/$CO$ and $H_2$/$CH_4$ are obtained as $3 \times 10^{27}$, $2 \times 10^{18}$, $1 \times 10^{17}$ and $6 \times 10^{46}$, respectively. Furthermore, we demonstrate that graphenylene-1 membrane exhibits the permeance of $H_2$ and He molecules are much higher than the value of them in the current industrial applications specially at temperatures above 300 K and 150 K, respectively. We further performed MD simulations to confirm the results of DFT calculations. All these results show that graphenylene-1 monolayer membrane is an excellent candidate for $H_2$ purification and He separation.