High-efficiency CO2 capture and separation over N2 in penta-graphene pores: insights from GCMC and DFT simulations

Abstract

CO2 capture and separation over N2 in penta-graphene (PG) slit pores (PG-x, x = 7−12) were investigated by using grand canonical Monte Carlo (GCMC) and density functional theory (DFT) simulations. GCMC results showed that PG pores exhibit high-efficiency CO2 capture and separation over N2. The best performing PG-8 exhibited an extraordinary CO2 adsorption capacity of 8.11 mmol/g at 1 bar and 5.56 mmol/g at 0.15 bar, respectively, with a high CO2/N2 selectivity of 69 at 1 bar and 298 K. The relative concentration distribution analyses illustrated that gas molecules were mainly adsorbed nearby PG nanosheet at their equilibrium states. DFT results showed that CO2 had a higher adsorption energy than that of N2 on PG nanosheet, further demonstrating PG pore as a promising material for CO2 capture and separation.