Single-layered fluorinated graphene nanopores for H₂/CH₄ and H₂/CO₂ separation with high efficiency and selectivity

The utilization of hydrogen gas (H₂) as an energy resource is a critical alternative to relieve the current greenhouse effect exacerbated by the excessive use of fossil fuels. The production of pure H₂ is usually achieved by its separation from H₂/CH₄ and H₂/CO₂ mixtures; however, such process still represents a great challenge due to the inevitable contamination that occurs after the membrane sieving. Here, we investigate the ability of a 2-dimensional material, a nanoporous fluorinated graphene (F-GRA), to perform the separation of H₂/CH₄ and H₂/CO₂ using molecular dynamics simulations. We generated three representative nanopores with different morphologies in F-GRA sheets to separately explore their sieving performances for the H₂ separation in the H₂/CH₄ and H₂/CO₂ mixtures. Our results revealed that the three F-GRA pores have an excellent performance for the H₂/CH₄ separation, displaying a high permeance for H₂ (over 10⁴ GPU) and a complete rejection for CH₄; these results suggest an ideal permeability and selectivity for these 2D systems. Additionally, two F-GRA pores, namely, pore2 and pore3, also displayed high separation performance in the case of the H₂/CO₂ mixture, while the remaining pore, namely, pore1, exhibit poor performance due to the tight obstruction of the CO₂ gas inside the nanopore. Combined, our findings exploit the utilization of the nanoporous F-GRA 2D material for the separation of H₂/CH₄ and H₂/CO₂ gas mixtures, which might open new possibilities for the future of gas sieving membrane preparation.