Combined Nuclear Magnetic Resonance and Molecular Dynamics Study of Methane Adsorption in M2 (dobdc) Metal–Organic Frameworks
- Univ. of California, Berkeley, CA (United States)
- Ecole Polytechnique Federale Lausanne (Switzlerland)
- RWTH Aachen Univ. (Germany)
- Univ. of California, Berkeley, CA (United States); Ecole Polytechnique Federale Lausanne (Switzlerland)
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
We investigate the diffusion of methane in the metal-organic frameworks M2 (dobdc) (M = Mg, Ni, Zn; dobdc4- = 2,5-dioxido-1,4-benzenedicarboxylate) as a function of methane loading through a combination of nuclear magnetic resonance and molecular dynamics simulations. At low gas densities, our results suggest that favorable CH4 -CH4 interactions lower the free energy barrier for methane hopping between coordinatively unsaturated metal sites and thus enhance the translational motion of methane down the c-axis. At higher gas densities, CH4 -CH4 interactions become more significant, CH4 -CH4 collisions become more frequent, and the gas self-diffusion begins to decrease. Lastly, we determine that the self-diffusion coefficient of methane is inversely related to the binding energy at the coordinatively unsaturated metal sites, such that diffusion is most rapid in the Zn2(dobdc) framework.
- Research Organization:
- Energy Frontier Research Centers (EFRC) (United States). Center for Gas Separations Relevant to Clean Energy Technologies (CGS); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES); National Science Foundation (NSF); Aachen-California Network of Academic Exchange (DAAD Germany)
- Grant/Contract Number:
- AC02-05CH11231; SC0001015; DGE-1752814; DGE-1106400
- OSTI ID:
- 1542406
- Journal Information:
- Journal of Physical Chemistry. C, Vol. 123, Issue 19; ISSN 1932-7447
- Publisher:
- American Chemical SocietyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
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