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Flexible metal-organic frameworks (MOF) can show exceptional selectivity and capacity for adsorption of CO2. The incorporation of CO2 into flexible MOFs that have Cu2+ coordination centers and organic pillar ligands is accompanied by a distortion of the framework lattice arising from chemical interactions between these components and CO2 molecules. CO2 adsorption yields a reproducible lattice expansion that is enabled by the rotation of the pillar ligands. The structures of Cu2(pzdc)2(bpy) and Cu2(pzdc)2(bpe), CPL-2 and CPL-5, were evaluated using in situ synchrotron x-ray powder diffraction at room temperature at CO2 gas pressures up to 50 atm. The structural parameters exhibit hysteresis between pressurization and depressurization. The pore volume within CPL-2 and CPL-5 increases at elevated CO2 pressure due to a combination of the pillar ligand rotation and the overall expansion of the lattice. Volumetric CO2 adsorption measurements up to 50 atm reveal adsorption behavior consistent with the structural results, including a rapid uptake of CO2 at low pressure, saturation above 20 atm, and hysteresis evident as a retention of CO2 during depressurization. A significantly greater CO2 uptake is observed in CPL-5 in comparison with predictions based on CO2 pressure-induced expansion of the pore volume available for adsorption, indicating that the flexibility of the CPL structures is a key factor in enhancing adsorption capacity.
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DFTB based models of gas molecules adsorbed in functionalized carbophenes
Molecular data of functionalized carbophenes, gas molecules, and gas molecules adsorbed by functionalized carbophenes. All data was produced using density functional tight-binding theory. The data is divided into three text files, each containing the data in the edn extensible data format. A fourth file is an example job script used for creating a DFTB+ input file and running the code on the Mana cluster at the University of Hawaiʻi at Mānoa. Version 1 of this data contained incorrect adsorption energies of CO2 molecules into the pores of the functionalized carbophenes. The errors came from accidentally using the total energy of CO2 as computed in DFTB+ using Universal Force Field parameters for the long-range energy corrections. In contrast, the data set used DFTB+ with Grimme’s D3 dispersion corrections. In Version 2, we corrected the adsorption energy values in the Gas_molecules_in_functionalized_carbophenes.txt records. The file Gas_molecules.txt now includes records for N2 and O2 which were used in computing the formation energies recorded in Gas_molecules_in_functionalized_carbophenes.txt. In creating producing Version 2, we accidentally missed five records. In Version 3, we added those five records back into Gas_molecules_in_functionalized_carbophenes.txt.
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- Award ID(s):
- 2113011
- PAR ID:
- 10562265
- Publisher / Repository:
- Mendeley Data
- Date Published:
- Edition / Version:
- 3
- Subject(s) / Keyword(s):
- Computational Materials Science Carbon Capture and Storage Hydrogen Capture Two-Dimensional Material
- Format(s):
- Medium: X Other: txt; shell_script
- Right(s):
- Creative Commons Attribution Non Commercial 3.0 Unported
- Sponsoring Org:
- National Science Foundation
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