A Computational Study on Phenyldiboronic Acid-Pillared Graphene Oxide Frameworks for Gas Storage and Separation

Potential applications of pillared graphene oxide frameworks (GOF) with phenyldiboronic acid linkers in gas storage and separation have been systematically explored using a combination of density functional theory calculations and Grand Canonical Monte Carlo simulations. A systematic computational screening of the efficiency of such frameworks in the capture and separation of a wide variety of potent greenhouse gases, as well as gases with significant applications in the energy sector, such as hydrogen and natural gas constituents, has been performed. A classical interaction potential model was employed for the pillared GOF, using the intramolecular geometry and atomic charges obtained by the quantum mechanical calculations. Well-established Lennard-Jones parameters for the nanoporous material and intermolecular potential models for the gases under investigation were also adopted. A high uptake of pure SF6, SO2, H2S, and CO2 has been observed at ambient pressures and temperatures. The CF4 and N2O uptake values at ambient pressure are also among the highest values reported in the literature. The pure H2 uptake reaches the United States Department of Energy targets at low temperatures (77 K) and pressures P > 5 bar, while the total volumetric uptake for CH4 at 50 bar and ambient temperature compares well with the most efficient adsorbents for methane storage. The simulations also revealed that the investigated type of materials is efficient for the separation of SF6–N2, CO2–H2, and H2S-CH4 fluid mixtures. In general, the present work indicates that this particular class of porous frameworks can have applications in industrial-scale gas storage and separation and greenhouse-gas capture to prevent global warming and climate change.