Strain-tunable self-passivated porous phosphorene for high-efficiency helium separation

The skyrocketing demand for helium (He) has stressed the limitation of the global He storge. The helium-rich natural gas represents the most accessible resource of He, thus the development of effective ways to extract He from natural gas is of high priority on the research agenda. The membrane-based separation technique is regarded as a promising method for efficient He purification that might possibly mitigate the current He shortage. In this work, by employing first-principles calculations together with molecular dynamics simulations, we predicted that both the strained and unstrained self-passivated porous phosphorene membrane can be used for efficient He harvest from natural gas. The results demonstrate that the porous phosphorene exhibits high He selectivities (10(4)-10(18)) over impure molecules (CO, N-2, CO2, CH4) and high He permeance of 10(-3) mol m(-2) s(-1) Pa-1 at 300 K, both far exceeding the industry standard. More importantly, the He permeance of the porous phosphorene can be effectively regulated under moderate strain along with high selectivity. Therefore, the porous phosphorene presented in this study is a robust and mechanically-controlled semipermeable membrane for efficient He purification that holds a great prospect in industrial application.