Molecular Dynamics Simulations of Gas Diffusion in Metal−Organic Frameworks:  Argon in CuBTC

Abstract

The class of coordination polymers known as metal-organic frameworks (MOFs) has three-dimensional porous structures that are considered as a promising alternative to zeolites and other nanoporous materials for catalysis, gas adsorption, and gas separation applications. In this paper, we present the first study of gas diffusion inside an MOF and compare the observed diffusion to known behaviors in zeolites. Using grand canonical Monte Carlo and equilibrium molecular dynamics, we calculate the adsorption isotherm and self-, corrected, and transport diffusivities for argon in the CuBTC metal-organic framework. Our results indicate that diffusion of Ar in CuBTC is very similar to Ar diffusion in silica zeolites in magnitude, concentration, and temperature dependence. This conclusion appears to apply to a broad range of MOF structures.

Recent Advances in Molecular Dynamics Simulations of Gas Diffusion in Metal Organic Frameworks

“…(Skoulidas, 2004) Results showed that diffusion in CuBTC MOF is an activated process as in zeolites. The calculated diffusivities of Ar in CuBTC were similar to the diffusion in zeolites both in magnitude and concentration dependence.…”

Molecular simulation of hydrogen diffusion in interpenetrated metal–organic frameworks

“…During the simulations, the potential energy and force at any position in the adsorbent were determined by interpolation. 23 …”

Stress-Induced Chemical Detection Using Flexible Metal−Organic Frameworks

“…Atomistic methods, such as molecular dynamics and Monte Carlo techniques, are particularly attractive for this purpose, due to their ability to treat a wide variety of related chemical systems coupled with relatively high computational efficiency for large-scale systems. 11 The prototypical MOF compound in computational studies has been IRMOF-1 (also known as MOF-5), which consists of Zn 4 16,25,26 These previous investigations employed standard force fields to model the interaction between the MOF and molecules within its pores, such as the universal force field, 27 DREIDING force field, 28 and OPLS force field, 29 or by custom optimization of Lennard-Jones potentials. 23 In all cases, the atoms within the MOF were not allowed to move during the simulation.…”