Highly porous ionic rht metal-organic framework for H2 and CO2 storage and separation: A molecular simulation study

Handle URI:
http://hdl.handle.net/10754/561488
Title:
Highly porous ionic rht metal-organic framework for H2 and CO2 storage and separation: A molecular simulation study
Authors:
Babarao, Ravichandar; Eddaoudi, Mohamed ( 0000-0003-1916-9837 ) ; JIANG, Jianwen
Abstract:
The storage and separation of H2 and CO2 are investigated in a highly porous ionic rht metal-organic framework (rht-MOF) using molecular simulation. The rht-MOF possesses a cationic framework and charge-balancing extraframework NO3 - ions. Three types of unique open cages exist in the framework: rhombicuboctahedral, tetrahedral, and cuboctahedral cages. The NO3 - ions exhibit small mobility and are located at the windows connecting the tetrahedral and cuboctahedral cages. At low pressures, H2 adsorption occurs near the NO 3 - ions that act as preferential sites. With increasing pressure, H2 molecules occupy the tetrahedral and cuboctahedral cages and the intersection regions. The predicted isotherm of H2 at 77 K agrees well with the experimental data. The H2 capacity is estimated to be 2.4 wt % at 1 bar and 6.2 wt % at 50 bar, among the highest in reported MOFs. In a four-component mixture (15:75:5:5 CO2/H 2/CO/CH4) representing a typical effluent gas of H 2 production, the selectivity of CO2/H2 in rht-MOF decreases slightly with increasing pressure, then increases because of cooperative interactions, and finally decreases as a consequence of entropy effect. By comparing three ionic MOFs (rht-MOF, soc-MOF, and rho-ZMOF), we find that the selectivity increases with increasing charge density or decreasing free volume. In the presence of a trace amount of H2O, the interactions between CO2 and NO3 - ions are significantly shielded by H2O; consequently, the selectivity of CO 2/H2 decreases substantially. © 2010 American Chemical Society.
KAUST Department:
Advanced Membranes and Porous Materials Research Center; Biological and Environmental Sciences and Engineering (BESE) Division; Physical Sciences and Engineering (PSE) Division; Chemical Science Program; Functional Materials Design, Discovery and Development (FMD3)
Publisher:
American Chemical Society
Journal:
Langmuir
Issue Date:
6-Jul-2010
DOI:
10.1021/la100509g
Type:
Article
ISSN:
07437463
Sponsors:
We gratefully acknowledge the support from the National University of Singapore (R-279-000-297-112).
Appears in Collections:
Articles; Advanced Membranes and Porous Materials Research Center; Physical Sciences and Engineering (PSE) Division; Functional Materials Design, Discovery and Development (FMD3); Chemical Science Program; Biological and Environmental Sciences and Engineering (BESE) Division

Full metadata record

DC FieldValue Language
dc.contributor.authorBabarao, Ravichandaren
dc.contributor.authorEddaoudi, Mohameden
dc.contributor.authorJIANG, Jianwenen
dc.date.accessioned2015-08-02T09:12:36Zen
dc.date.available2015-08-02T09:12:36Zen
dc.date.issued2010-07-06en
dc.identifier.issn07437463en
dc.identifier.doi10.1021/la100509gen
dc.identifier.urihttp://hdl.handle.net/10754/561488en
dc.description.abstractThe storage and separation of H2 and CO2 are investigated in a highly porous ionic rht metal-organic framework (rht-MOF) using molecular simulation. The rht-MOF possesses a cationic framework and charge-balancing extraframework NO3 - ions. Three types of unique open cages exist in the framework: rhombicuboctahedral, tetrahedral, and cuboctahedral cages. The NO3 - ions exhibit small mobility and are located at the windows connecting the tetrahedral and cuboctahedral cages. At low pressures, H2 adsorption occurs near the NO 3 - ions that act as preferential sites. With increasing pressure, H2 molecules occupy the tetrahedral and cuboctahedral cages and the intersection regions. The predicted isotherm of H2 at 77 K agrees well with the experimental data. The H2 capacity is estimated to be 2.4 wt % at 1 bar and 6.2 wt % at 50 bar, among the highest in reported MOFs. In a four-component mixture (15:75:5:5 CO2/H 2/CO/CH4) representing a typical effluent gas of H 2 production, the selectivity of CO2/H2 in rht-MOF decreases slightly with increasing pressure, then increases because of cooperative interactions, and finally decreases as a consequence of entropy effect. By comparing three ionic MOFs (rht-MOF, soc-MOF, and rho-ZMOF), we find that the selectivity increases with increasing charge density or decreasing free volume. In the presence of a trace amount of H2O, the interactions between CO2 and NO3 - ions are significantly shielded by H2O; consequently, the selectivity of CO 2/H2 decreases substantially. © 2010 American Chemical Society.en
dc.description.sponsorshipWe gratefully acknowledge the support from the National University of Singapore (R-279-000-297-112).en
dc.publisherAmerican Chemical Societyen
dc.titleHighly porous ionic rht metal-organic framework for H2 and CO2 storage and separation: A molecular simulation studyen
dc.typeArticleen
dc.contributor.departmentAdvanced Membranes and Porous Materials Research Centeren
dc.contributor.departmentBiological and Environmental Sciences and Engineering (BESE) Divisionen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.contributor.departmentChemical Science Programen
dc.contributor.departmentFunctional Materials Design, Discovery and Development (FMD3)en
dc.identifier.journalLangmuiren
dc.contributor.institutionDepartment of Chemical and Biomolecular Engineering, National University of Singapore, 117576 Singapore, Singaporeen
dc.contributor.institutionDepartment of Chemistry, University of South Florida, Tampa, FL 33620, United Statesen
kaust.authorEddaoudi, Mohameden
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