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Publication in Nature Chemistry

Together with the group of Laura Gagliardi we studied the adsorption of CO2 in the metal organic framework MOF74. 

Coverage of this work at:

University of Minnesota

Lawrence Berkeley National Laboratory

The Energy Collective



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A. Dzubak, L.-C. Lin, J. Kim, J. A. Swisher, R. Poloni, S. N. Maximoff, B. Smit, and L. Gagliardi, Ab-initio Carbon Capture in Open-Site Metal Organic Frameworks Nat Chem  (2012) http://dx.doi.org/0.1038/NCHEM.1432



Cover of PCCP

We ended up on the cover with our molecular simulations of Forrest on diffusion in zeolites.

M. K. F. Abouelnasr and B. Smit, Diffusion in confinement: kinetic simulations of self- and collective diffusion behavior of adsorbed gases PCCP 14 (33), 11600 (2012) http://dx.doi.org/10.1039/C2CP41147D

Abstract

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The self- and collective-diffusion behaviors of adsorbed methane, helium, and isobutane in zeolite frameworks LTA, MFI, AFI, and SAS were examined at various concentrations using a range of molecular simulation techniques including Molecular Dynamics (MD), Monte Carlo (MC), Bennett–Chandler (BC), and kinetic Monte Carlo (kMC). This paper has three main results. (1) A novel model for the process of adsorbate movement between two large cages was created, allowing the formulation of a mixing rule for the re-crossing coefficient between two cages of unequal loading. The predictions from this mixing rule were found to agree quantitatively with explicit simulations. (2) A new approach to the dynamically corrected Transition State Theory method to analytically calculate self-diffusion properties was developed, explicitly accounting for nanoscale fluctuations in concentration. This approach was demonstrated to quantitatively agree with previous methods, but is uniquely suited to be adapted to a kMC simulation that can simulate the collective-diffusion behavior. (3) While at low and moderate loadings the self- and collective-diffusion behaviors in LTA are observed to coincide, at higher concentrations they diverge. A change in the adsorbate packing scheme was shown to cause this divergence, a trait which is replicated in a kMC simulation that explicitly models this behavior. These phenomena were further investigated for isobutane in zeolite MFI, where MD results showed a separation in self- and collective- diffusion behavior that was reproduced with kMC simulations.

© Berend Smit 2019