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Title: Methane Storage: Molecular Mechanisms Underlying Room-Temperature Adsorption in Zn 4O(BDC) 3 (MOF-5)

Here, we study how the methane adsorption properties of the ionic MOF-5 are derived from the local structure of its coordinated metal-cluster. Density functional theory is used to study the adsorption process and identify the key interactions which drive it at ambient temperatures. A detailed adsorption model which represents the adsorption process is derived and used to extract thermodynamic properties from previously reported adsorption isotherms. We find that after adsorption of a single molecule to the face of the metal cluster, a nanostructured surface is formed which enables adsorption of additional CH 4 molecules at reduced entropic penalty thanks to on-surface hopping motions and retention of significant translational freedom. Binding of the CH 4 molecules to the MOF is dominated by electrostatic interactions with negatively charged carboxylate groups, while CH 4-CH 4 dispersion interactions are important only at high pressures. Last, the MOF-specific adsorption model is compared against the single-site Langmuir model.
Authors:
 [1] ; ORCiD logo [2]
  1. Univ. of California, Berkeley, CA (United States). Dept. of Chemistry; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division
  2. Univ. of California, Berkeley, CA (United States). Dept. of Chemistry; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Chemical Sciences Division
Publication Date:
Grant/Contract Number:
AC02-05CH11231; CHE-1363342
Type:
Accepted Manuscript
Journal Name:
Journal of Physical Chemistry. C
Additional Journal Information:
Journal Volume: 121; Journal Issue: 22; Related Information: © 2017 American Chemical Society.; Journal ID: ISSN 1932-7447
Publisher:
American Chemical Society
Research Org:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); USDOE Office of Energy Efficiency and Renewable Energy (EERE), Fuel Cell Technologies Office (EE-3F); National Science Foundation (NSF)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 74 ATOMIC AND MOLECULAR PHYSICS
OSTI Identifier:
1464148