Title: Gas Adsorption and Dynamics in Pillared Graphene Frameworks,
Abstract: Pillared Graphene Frameworks are a novel class of microporous materials made
by graphene sheets separated by organic spacers. One of their main features is
that the pillar type and density can be chosen to tune the material properties.
In this work, we present a computer simulation study of adsorption and dynamics
of H$_{4}$, CH$_{2}$, CO$_{2}$, N$_{2}$ and O$_{2}$ and binary mixtures
thereof, in Pillared Graphene Frameworks with nitrogen-containing organic
spacers. In general, we find that pillar density plays the most important role
in determining gas adsorption. In the low-pressure regime (< 10 bar) the amount
of gas adsorbed is an increasing function of pillar density. At higher
pressures the opposite trend is observed. Diffusion coefficients were computed
for representative structures taking into account the framework flexibility
that is essential in assessing the dynamical properties of the adsorbed gases.
Good performance for the gas separation in CH$_{4}$/H$_{2}$, CO$_{2}$/H$_{2}$
and CO$_{2}$/N$_{2}$ mixtures was found with values comparable to those of
metal-organic frameworks and zeolites.