Force Field Development from Periodic Density Functional Theory Calculations for Gas Separation Applications Using Metal-Organic Frameworks
Journal
Journal of Physical Chemistry C
Journal Volume
120
Journal Issue
23
Pages
12590-12604
Date Issued
2016
Author(s)
Mercado R.
Vlaisavljevich B.
Lin L.-C.
Lee K.
Lee Y.
Mason J.A.
Xiao D.J.
Gonzalez M.I.
Kapelewski M.T.
Neaton J.B.
Smit B.
Abstract
We present accurate force fields developed from density functional theory (DFT) calculations with periodic boundary conditions for use in molecular simulations involving M2(dobdc) (M-MOF-74; dobdc4- = 2,5-dioxidobenzenedicarboxylate; M = Mg, Mn, Fe, Co, Ni, Zn) and frameworks of similar topology. In these systems, conventional force fields fail to accurately model gas adsorption due to the strongly binding open-metal sites. The DFT-derived force fields predict the adsorption of CO2, H2O, and CH4 inside these frameworks much more accurately than other common force fields. We show that these force fields can also be used for M2(dobpdc) (dobpdc4- = 4,4′-dioxidobiphenyl-3,3′-dicarboxylate), an extended version of MOF-74, and thus are a promising alternative to common force fields for studying materials similar to MOF-74 for carbon capture applications. Furthermore, it is anticipated that the approach can be applied to other metal-organic framework topologies to obtain force fields for different systems. We have used this force field to study the effect of contaminants such as H2O and N2 upon these materials' performance for the separation of CO2 from the emissions of natural gas reservoirs and coal-fired power plants. Specifically, mixture adsorption isotherms calculated with these DFT-derived force fields showed a significant reduction in the uptake of many gas components in the presence of even trace amounts of H2O vapor. The extent to which the various gases are affected by the concentration of H2O in the reservoir is quantitatively different for the different frameworks and is related to their heats of adsorption. Additionally, significant increases in CO2 selectivities over CH4 and N2 are observed as the temperature of the systems is lowered. ? 2016 American Chemical Society.
Subjects
Adsorption
Binding sites
Carbon
Carbon dioxide
Carboxylation
Coal
Crystalline materials
Fossil fuel power plants
Gas adsorption
Gas emissions
Gas plants
Gases
Java programming language
Manganese
Natural gas fields
Organic polymers
Organometallics
Topology
Coal-fired power plant
Force field development
Heats of adsorption
Metal organic framework
Molecular simulations
Natural gas reservoir
Periodic boundary conditions
Periodic density functional theory calculations
Density functional theory
Type
journal article