First-principles design of nano-porous graphene membranes for efficient separation of halogen gases

Abstract

The development of efficient membranes for separating the mixture of gases is an active area for research. Atomically thick layers of 2-D materials can serve as a potential candidate for ultra-thin membranes. Here, we investigated the capability of nano porous graphene (NPG) membranes towards efficient halogen separation. Porosity was induced in graphene membranes via deliberate removal of host C atoms. A number of vacancies viz. 4, 6a, 6b, 8 and 10 were examined with and without functionalization to gauge the halogen selectivity of these NPG membranes. Analysis of potential energy profiles reveal that no selectivity could be obtained without functionalization of the pore rim. However, after functionalizing the pore via F/Cl/H, NPG membranes could possibly differentiate between the halogen molecules. Further, separation of F2 could be obtained by using either of the 6a-1F, 6a-3F or 6b-1F NPG membranes while the same for I2 molecules was obtained via 8V-1F/8V-1Cl/8V-2H membranes. Present findings pledge towards potential applications for efficient ultra-thin membranes for halogen separation.