%0 Journal Article
%A Franz, Douglas
%A Forrest, Katherine
A.
%A Pham, Tony
%A Space, Brian
%D 2016
%T Accurate H2 Sorption Modeling in the rht-MOF NOTT-112 Using Explicit Polarization
%U https://acs.figshare.com/articles/journal_contribution/Accurate_H_sub_2_sub_Sorption_Modeling_in_the_i_rht_i_-MOF_NOTT-112_Using_Explicit_Polarization/3798936
%R 10.1021/acs.cgd.6b01058.s001
%2 https://acs.figshare.com/ndownloader/files/5914557
%K NOTT -112.
%K H 2 sorption isotherms
%K H 2 sorption
%K GCMC
%K Explicit Polarization Hydrogen sorption
%K NPD
%K Grand canonical Monte Carlo
%K open-metal sites
%K interaction
%K gas sorption behavior
%K Cu
%K Accurate H 2 Sorption Modeling
%K NOTT -112
%K MOF NOTT -112
%K data
%K neutron powder diffraction
%X Hydrogen
sorption was characterized theoretically in NOTT-112,
an rht-metal–organic framework (MOF) that
consists of Cu2+ ions coordinated to 1,3,5-tris(3′,5′-dicarboxy[1,1′-biphenyl]-4-yl)benzene
ligands. Grand canonical Monte Carlo (GCMC) simulations of H2 sorption were performed using three different sorbate potentials
of increasing complexity to elucidate the mechanism of interaction
in NOTT-112. Reasonable agreement with the experimental H2 sorption isotherms, isosteric heats of adsorption (Qst), and H2–Cu2+ distances
was obtained with the model that includes explicit many-body polarization.
This highlights the physical importance of induction in H2 sorption in MOFs with open-metal sites. The two Cu2+ ions
within the paddlewheels in NOTT-112 have distinct electrostatic profiles
and sorption characteristics. The Cu2+ ions projecting
into the cuboctahedral (cub–Oh)
cage of the MOF are more electropositive than the Cu2+ ions
projecting toward the organic linker, and therefore serve as the initial
loading sites. Such a sorption mechanism has been shown to be sensitive
and tunable via the magnitude of the metal charge. Simulated sorption
onto the open-metal sites was compared with extant experimental neutron
powder diffraction (NPD) data in NOTT-112. Simulated annealing calculations
on sorbates and analysis of the radial distribution function for H2 sorbed about the Cu2+ ions revealed metal–sorbate
interaction distances that were in reasonable agreement with NPD data
in NOTT-112 for the most realistic model. This study demonstrates
how the inclusion of explicit polarization in classical GCMC simulation
is able to reproduce experimental observables and elucidate the gas
sorption behavior in a MOF possessing open-metal sites. Additionally,
this study shows how careful modeling of the MOF–sorbate interactions
can provide complementary atomistic resolution to data obtained from
NPD measurements.
%I ACS Publications