Effect of strain engineering on the highly controllable H2 purification performance of graphenylene-like boron nitride membranes: DFT calculations and MD simulations

To obtain high-purity hydrogen for industrial applications, it is highly desirable to separate and purify hydrogen from byproduct gases in hydrogen preparation. DFT calculations and MD simulations were performed to study the hydrogen separation performance of the graphenylene-like boron nitride (p-BN) monolayer under the modification of strain engineering. The p-BN membrane is thermal stable at high temperatures of 1500 K. Without strain engineering, the p-BN monolayer cannot be used as H₂ separation membranes at room temperature, as no H₂ gas can permeate from the membrane, however, it would be potential for H₂ separation at high temperatures (the H₂ permeance of 3.415 × 10⁵-2.732 × 10⁶ GPU with high selectivity above 500 K). Strain engineering can effectively enhance the H₂ purification properties of the p-BN monolayer. At 9 % strains, the H₂ permeability of the p-BN membrane is 2.357 × 10⁷ GPU at 300 K, much higher than the industrial acceptance value, while the selectivity of H₂ related to other gases (N₂, CO, O₂, CO₂, and CH₄) is 14.75, 33.09, 1.002 × 10², 8.512 × 10⁵, and 1.502 × 10¹⁰, respectively. Therefore, our findings indicate that the p-BN membranes are excellent candidates for highly controllable and reversible H₂ separation and purification under modification of strain engineering.