EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

A promising application of porous graphene is that of membrane for gas separation. In the present work, we apply DFT approximations to calculate the energy barriers, and subsequently, we estimate the permeation of several molecular systems through pores in single-layer graphene. Our calculations are at the level of hybrid-meta GGA functionals. Several different kinds of pores were considered differing in size, shape, and stoichiometry. The goal is to determine the size and type of pores with optimal permeability and selectivity for the application of gas separation. We particularly focus on pores created by carbon vacancies and nitrogen doping (pyridinic, pyrrolic defects). We demonstrate that the size of interest for gas separation is 0.5 nm and that pyridinic pores are the most efficient among the types we examined. We also find examples of pores with industrially acceptable permeance that can effectively separate gases. In addition, we consider pore stacking in bilayer graphene which is studied with atomistic simulations. We show that combinations of pores can be used to enhance/suppress molecular permeability in a non-additive manner.
Acknowledgments: This research is funded by the projects: 1) GATES, “Nanoporous Graphene membrane made without Transfer for gas Separation”, Flag-ERA JTC‐PCI2018‐093137, MIS: 5041612; 2) “National Infrastructure in Nanotechnology, Advanced Materials, and Micro-Nanoelectronics”, MIS: 5002772; Action: “Reinforcement of the Research and Innovation Infrastructure”, funded by the Operational Programme "Competitiveness, Entrepreneurship and Innovation" (NSRF 2014-2020)