Point-Defect Segregation and Space-Charge Potentials at the Σ5(310)[001] Grain Boundary in Ceria
The atomistic structure and point-defect thermodynamics of the model Σ5(310)[001] grain boundary in CeO2 were explored with atomistic simulations. An interface with a double-diamond-shaped structural repeat unit was found to have the lowest energy. Segregation energies were calculated for oxygen v...
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Multidisciplinary Digital Publishing Institute
2024
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| Online Access: | https://hdl.handle.net/1721.1/157268 |
| _version_ | 1824458369558118400 |
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| author | Usler, Adrian L. Heelweg, Henrik J. De Souza, Roger A. Genreith-Schriever, Annalena R. |
| author2 | Massachusetts Institute of Technology. Department of Chemistry |
| author_facet | Massachusetts Institute of Technology. Department of Chemistry Usler, Adrian L. Heelweg, Henrik J. De Souza, Roger A. Genreith-Schriever, Annalena R. |
| author_sort | Usler, Adrian L. |
| collection | MIT |
| description | The atomistic structure and point-defect thermodynamics of the model Σ5(310)[001]
grain boundary in CeO2 were explored with atomistic simulations. An interface with a double-diamond-shaped structural repeat unit was found to have the lowest energy. Segregation energies were calculated for oxygen vacancies, electron polarons, gadolinium and scandium acceptor cations, and tantalum donor cations. These energies deviate strongly from their bulk values over the same length scale, thus indicating a structural grain-boundary width of approximately 1.5 nm. However, an analysis revealed no unambiguous correlation between segregation energies and local structural descriptors, such as interatomic distance or coordination number. From the segregation energies, the grain-boundary space-charge potential in Gouy–Chapman and restricted-equilibrium regimes was calculated as a function of temperature for dilute solutions of (i) oxygen vacancies and acceptor cations and (ii) electron polarons and donor cations. For the latter, the space-charge potential is predicted to change from negative to positive in the restricted-equilibrium regime. For the former, the calculation of the space-charge potential from atomistic segregation energies is shown to require the inclusion of the segregation energies for acceptor cations. Nevertheless, the space-charge potential in the restricted-equilibrium regime can be described well with an empirical model employing a single effective oxygen-vacancy segregation energy. |
| first_indexed | 2025-02-19T04:24:48Z |
| format | Article |
| id | mit-1721.1/157268 |
| institution | Massachusetts Institute of Technology |
| last_indexed | 2025-02-19T04:24:48Z |
| publishDate | 2024 |
| publisher | Multidisciplinary Digital Publishing Institute |
| record_format | dspace |
| spelling | mit-1721.1/1572682025-01-10T04:20:15Z Point-Defect Segregation and Space-Charge Potentials at the Σ5(310)[001] Grain Boundary in Ceria Usler, Adrian L. Heelweg, Henrik J. De Souza, Roger A. Genreith-Schriever, Annalena R. Massachusetts Institute of Technology. Department of Chemistry The atomistic structure and point-defect thermodynamics of the model Σ5(310)[001] grain boundary in CeO2 were explored with atomistic simulations. An interface with a double-diamond-shaped structural repeat unit was found to have the lowest energy. Segregation energies were calculated for oxygen vacancies, electron polarons, gadolinium and scandium acceptor cations, and tantalum donor cations. These energies deviate strongly from their bulk values over the same length scale, thus indicating a structural grain-boundary width of approximately 1.5 nm. However, an analysis revealed no unambiguous correlation between segregation energies and local structural descriptors, such as interatomic distance or coordination number. From the segregation energies, the grain-boundary space-charge potential in Gouy–Chapman and restricted-equilibrium regimes was calculated as a function of temperature for dilute solutions of (i) oxygen vacancies and acceptor cations and (ii) electron polarons and donor cations. For the latter, the space-charge potential is predicted to change from negative to positive in the restricted-equilibrium regime. For the former, the calculation of the space-charge potential from atomistic segregation energies is shown to require the inclusion of the segregation energies for acceptor cations. Nevertheless, the space-charge potential in the restricted-equilibrium regime can be described well with an empirical model employing a single effective oxygen-vacancy segregation energy. 2024-10-11T21:42:43Z 2024-10-11T21:42:43Z 2024-08-03 2024-09-27T13:18:14Z Article http://purl.org/eprint/type/JournalArticle https://hdl.handle.net/1721.1/157268 Usler, A.L.; Heelweg, H.J.; De Souza, R.A.; Genreith-Schriever, A.R. Point-Defect Segregation and Space-Charge Potentials at the Σ5(310)[001] Grain Boundary in Ceria. Solids 2024, 5, 404-421. PUBLISHER_CC http://dx.doi.org/10.3390/solids5030027 solids Creative Commons Attribution https://creativecommons.org/licenses/by/4.0/ application/pdf Multidisciplinary Digital Publishing Institute Multidisciplinary Digital Publishing Institute |
| spellingShingle | Usler, Adrian L. Heelweg, Henrik J. De Souza, Roger A. Genreith-Schriever, Annalena R. Point-Defect Segregation and Space-Charge Potentials at the Σ5(310)[001] Grain Boundary in Ceria |
| title | Point-Defect Segregation and Space-Charge Potentials at the Σ5(310)[001] Grain Boundary in Ceria |
| title_full | Point-Defect Segregation and Space-Charge Potentials at the Σ5(310)[001] Grain Boundary in Ceria |
| title_fullStr | Point-Defect Segregation and Space-Charge Potentials at the Σ5(310)[001] Grain Boundary in Ceria |
| title_full_unstemmed | Point-Defect Segregation and Space-Charge Potentials at the Σ5(310)[001] Grain Boundary in Ceria |
| title_short | Point-Defect Segregation and Space-Charge Potentials at the Σ5(310)[001] Grain Boundary in Ceria |
| title_sort | point defect segregation and space charge potentials at the sigma 5 310 001 grain boundary in ceria |
| url | https://hdl.handle.net/1721.1/157268 |
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