Theoretical Prediction of High Pressure Methane Adsorption in Porous Aromatic Frameworks (PAFs)

Abstract

The adsorption isotherms of methane in four micro- and mesoporous materials, based on the diamond structure with (poly)phenyl chains inserted in all the C-C bonds, have been simulated with Grand Canonical Monte Carlo technique. The pressure range was extended above 250 bar and the isotherms were computed at 298, 313, and 353 K, to explore the potentiality of these materials for automotive applications, increasing the capacity of high-pressure tanks or storing a comparable amount of gas at much lower pressure. The force field employed in the simulations was optimized to fit the correct behavior of the free gas in all the pressure range and to reproduce the methane-phenyl interactions computed at high quantum mechanical level (post Hartree-Fock). All the examined materials showed a high affinity for methane, ensuring a larger storage of gas than simple compression in all the conditions: two samples exceeded the target proposed by U.S. Department of Energy for methane storage in low-pressure fuel tanks (180 cm(3) (STP)/cm(3) at 35 bar and room temperature).

The right isotherms for the right reasons? Validation of generic force fields for prediction of methane adsorption in metal-organic frameworks

“…Since then, GCMC has been employed to predict CH4 adsorption isotherms in a wide range of MOFs and related structures [14,15,16,17,18,19,20,21,22,23], with reasonable agreement with experiment reported in many cases.…”

An atomistic model of a disordered nanoporous solid: Interplay between Monte Carlo simulations and gas adsorption experiments

“…This model, referred to as mPAF-FCL, was easily prepared starting from the periodic structure of PAF-301, 30,36,53 i. e. a diamond network with a phenyl ring inserted in each CC bond: every two tetracoordinated carbons, two phenyl rings were replaced by hydrogen atoms as illustrated in Figure 2, and the structure was optimized by CRYSTAL09 with periodic boundary conditions. The resulting solid is far denser than the laboratory sample (0.87 instead of 0.53 g/cm 3 ), showing that the model crosslinking is excessive.…”

Tetrahedral organic molecules as components in supramolecular architectures and in covalent assemblies, networks and polymers

“…HCP-11 is thermally stable up to 520 C in air and its absolute H 2 uptake can reach 10.7 wt% at 48 bar and 77 K, 127 its CO 2 uptake is 1300 mg g À1 at 40 bar and room temperature. 128 A theoretical simulation of high pressure methane adsorption of HCP-11 predicted a total methane uptake as high as 728 mg g À1 at 53.8 bar at 298 K. 129 Comotti studied the in situ solid-state polymerization of acrylonitrile in the cavities of HCP-11, proving that conned polymerization in porous frameworks leads to innovative nanostructured materials. 130 Zhou showed that post-functionalization of HCP-11 leads to enhanced properties.…”