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

Abstract: 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.