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Title: A first principles study of energetics and electronic structural responses of uranium-based coordination polymers to Np incorporation

Abstract

Abstract Recently developed coordination polymers (CPs) and metal organic frameworks (MOFs) may find applications in areas such as catalysis, hydrogen storage, and heavy metal immobilization. Research on the potential application of actinide-based CPs (An-CP/MOFs) is not as advanced as transition metal-based MOFs. In order to modify their structures necessary for optimizing thermodynamic and electronic properties, here, we described how a specific topology of a particular actinide-based CP or MOF responds to the incorporation of other actinides considering their diverse coordination chemistry associated with the multiple valence states and charge-balancing mechanisms. In this study, we apply a recently developed DFT-based method to determine the relative stability of transuranium incorporated CPs in comparison to their uranium counterpart considering both solid and aqueous state sources and sinks to understand the mechanism and energetics of charge-balanced Np 5+incorporation into three uranium-based CPs. The calculated Np 5++H +incorporation energies for these CPs range from 0.33 to 0.52 eV, depending on the organic linker, when using the solid oxide Np source Np 2O 5and U sink UO 3. Incorporation energies of these CPs using aqueous sources and sinks increase to 2.85–3.14 eV. The thermodynamic and structural analysis in this study aides in determining, why certain MOFmore » topologies and ligands are selective for some actinides and not for others. This means that once this method is extended across a variety of CPs with their respective linker molecules and different actinides, it can be used to identify certain CPs with certain organic ligands being specific for certain actinides. This information can be used to construct CPs for actinide separation. This is the first determination of the electronic structure (band structure, density of states) of these uranium- and transuranium-based CPs which may eventually lead to design CPs with certain optical or catalytic properties. While the reduction of the DFT-determined-bandgap goes from 3.1 eV to 2.4 eV when going from CP1 to CP3, showing the influence of the linker, Np 6+incorporation reduces the bandgap for CP1 and CP3, while increasing it for CP2. The coupled substitution of U 6+→Np 5++H +reduces the bandgap significantly, but only for CP3.« less

Authors:
;
Publication Date:
Research Org.:
Univ. of Michigan, Ann Arbor, MI (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1541925
DOE Contract Number:  
FG02-06ER15783
Resource Type:
Journal Article
Journal Name:
Radiochimica Acta
Additional Journal Information:
Journal Volume: 106; Journal Issue: 1; Journal ID: ISSN 0033-8230
Publisher:
de Gruyter
Country of Publication:
United States
Language:
English
Subject:
Chemistry; Nuclear Science & Technology

Citation Formats

Saha, Saumitra, and Becker, Udo. A first principles study of energetics and electronic structural responses of uranium-based coordination polymers to Np incorporation. United States: N. p., 2018. Web. doi:10.1515/ract-2016-2732.
Saha, Saumitra, & Becker, Udo. A first principles study of energetics and electronic structural responses of uranium-based coordination polymers to Np incorporation. United States. doi:10.1515/ract-2016-2732.
Saha, Saumitra, and Becker, Udo. Fri . "A first principles study of energetics and electronic structural responses of uranium-based coordination polymers to Np incorporation". United States. doi:10.1515/ract-2016-2732.
@article{osti_1541925,
title = {A first principles study of energetics and electronic structural responses of uranium-based coordination polymers to Np incorporation},
author = {Saha, Saumitra and Becker, Udo},
abstractNote = {Abstract Recently developed coordination polymers (CPs) and metal organic frameworks (MOFs) may find applications in areas such as catalysis, hydrogen storage, and heavy metal immobilization. Research on the potential application of actinide-based CPs (An-CP/MOFs) is not as advanced as transition metal-based MOFs. In order to modify their structures necessary for optimizing thermodynamic and electronic properties, here, we described how a specific topology of a particular actinide-based CP or MOF responds to the incorporation of other actinides considering their diverse coordination chemistry associated with the multiple valence states and charge-balancing mechanisms. In this study, we apply a recently developed DFT-based method to determine the relative stability of transuranium incorporated CPs in comparison to their uranium counterpart considering both solid and aqueous state sources and sinks to understand the mechanism and energetics of charge-balanced Np5+incorporation into three uranium-based CPs. The calculated Np5++H+incorporation energies for these CPs range from 0.33 to 0.52 eV, depending on the organic linker, when using the solid oxide Np source Np2O5and U sink UO3. Incorporation energies of these CPs using aqueous sources and sinks increase to 2.85–3.14 eV. The thermodynamic and structural analysis in this study aides in determining, why certain MOF topologies and ligands are selective for some actinides and not for others. This means that once this method is extended across a variety of CPs with their respective linker molecules and different actinides, it can be used to identify certain CPs with certain organic ligands being specific for certain actinides. This information can be used to construct CPs for actinide separation. This is the first determination of the electronic structure (band structure, density of states) of these uranium- and transuranium-based CPs which may eventually lead to design CPs with certain optical or catalytic properties. While the reduction of the DFT-determined-bandgap goes from 3.1 eV to 2.4 eV when going from CP1 to CP3, showing the influence of the linker, Np6+incorporation reduces the bandgap for CP1 and CP3, while increasing it for CP2. The coupled substitution of U6+→Np5++H+reduces the bandgap significantly, but only for CP3.},
doi = {10.1515/ract-2016-2732},
journal = {Radiochimica Acta},
issn = {0033-8230},
number = 1,
volume = 106,
place = {United States},
year = {2018},
month = {1}
}