TY - JOUR
T1 - Investigating H2 Sorption in a Fluorinated Metal-Organic Framework with Small Pores Through Molecular Simulation and Inelastic Neutron Scattering
AU - Forrest, Katherine A.
AU - Pham, Tony
AU - Georgiev, Peter A.
AU - Pinzan, Florian
AU - Cioce, Christian R.
AU - Unruh, Tobias
AU - Eckert, Juergen
AU - Space, Brian
N1 - Publisher Copyright:
© 2015 American Chemical Society.
PY - 2015/7/7
Y1 - 2015/7/7
N2 - Simulations of H2 sorption were performed in a metal-organic framework (MOF) consisting of Zn2+ ions coordinated to 1,2,4-triazole and tetrafluoroterephthalate ligands (denoted [Zn(trz)(tftph)] in this work). The simulated H2 sorption isotherms reported in this work are consistent with the experimental data for the state points considered. The experimental H2 isosteric heat of adsorption (Qst) values for this MOF are approximately 8.0 kJ mol-1 for the considered loading range, which is in the proximity of those determined from simulation. The experimental inelastic neutron scattering (INS) spectra for H2 in [Zn(trz)(tftph)] reveal at least two peaks that occur at low energies, which corresponds to high barriers to rotation for the respective sites. The most favorable sorption site in the MOF was identified from the simulations as sorption in the vicinity of a metal-coordinated H2O molecule, an exposed fluorine atom, and a carboxylate oxygen atom in a confined region in the framework. Secondary sorption was observed between the fluorine atoms of adjacent tetrafluoroterephthalate ligands. The H2 molecule at the primary sorption site in [Zn(trz)(tftph)] exhibits a rotational barrier that exceeds that for most neutral MOFs with open-metal sites according to an empirical phenomenological model, and this was further validated by calculating the rotational potential energy surface for H2 at this site. (Figure Presented).
AB - Simulations of H2 sorption were performed in a metal-organic framework (MOF) consisting of Zn2+ ions coordinated to 1,2,4-triazole and tetrafluoroterephthalate ligands (denoted [Zn(trz)(tftph)] in this work). The simulated H2 sorption isotherms reported in this work are consistent with the experimental data for the state points considered. The experimental H2 isosteric heat of adsorption (Qst) values for this MOF are approximately 8.0 kJ mol-1 for the considered loading range, which is in the proximity of those determined from simulation. The experimental inelastic neutron scattering (INS) spectra for H2 in [Zn(trz)(tftph)] reveal at least two peaks that occur at low energies, which corresponds to high barriers to rotation for the respective sites. The most favorable sorption site in the MOF was identified from the simulations as sorption in the vicinity of a metal-coordinated H2O molecule, an exposed fluorine atom, and a carboxylate oxygen atom in a confined region in the framework. Secondary sorption was observed between the fluorine atoms of adjacent tetrafluoroterephthalate ligands. The H2 molecule at the primary sorption site in [Zn(trz)(tftph)] exhibits a rotational barrier that exceeds that for most neutral MOFs with open-metal sites according to an empirical phenomenological model, and this was further validated by calculating the rotational potential energy surface for H2 at this site. (Figure Presented).
UR - http://www.scopus.com/inward/record.url?scp=84936806690&partnerID=8YFLogxK
U2 - 10.1021/acs.langmuir.5b01664
DO - 10.1021/acs.langmuir.5b01664
M3 - Article
AN - SCOPUS:84936806690
VL - 31
SP - 7328
EP - 7336
JO - Langmuir
JF - Langmuir
SN - 0743-7463
IS - 26
ER -