Ordering of oxygen vacancies and excess charge localization in bulk ceria: A DFT+U study
- Autores
- Murgida, Gustavo Ezequiel; Ferrari, Valeria Paola; Ganduglia Pirovano, Maria Veronica; Llois, Ana Maria
- Año de publicación
- 2014
- Idioma
- inglés
- Tipo de recurso
- artículo
- Estado
- versión publicada
- Descripción
- The importance of ceria (CeO2) in many applications originates from the ease of oxygen vacancy formation and healing. The ordering of vacancies and the whereabouts of the excess charge in bulk CeO2 are of no less significance than at ceria surfaces, but they have not received the same attention. In this work, the formation of neutral oxygen vacancies in bulk CeO2 is investigated using density-functional theory (DFT) in the DFT + U (U is an effective onsite Coulomb interaction parameter) approach for a broad range of vacancy concentrations Θ (1/64 ≤ Θ ≤ 1/4 ). We find that the excess charge prefers to be localized in cation sites such that the mean Ce3+ coordination number is maximized, and if nearest-neighbor cation sites are reduced, they rather be nonuniformly distributed. Furthermore, we show that a vacancy repels other vacancies from its nearest-neighbor shell and that the [110] and [111] directions are possible directions for clustering of second- and third-neighbor vacancies, respectively. Vacancies prefer not to share cations. The results are discussed in a simple physical picture which enables the separation of the different contributions to the averaged vacancy formation energy. We also consider cells with fluorite structure and same stoichiometries as in existing bulk phases, i.e., Ce11O20 (Θ = 1/11), Ce7 O12 (Θ = 1/7), and Ce2O3 (Θ = 1/4), as well as the corresponding real structures. We find that the vacancy ordering and the location of the excess electrons are consistent with the results for single-phase reduced CeO2, but the Ce11O20, Ce7O12, and Ce2O3 structures are substantially more stable. The stability of these phases as a function of pressure and temperature is discussed. Vacancy-induced lattice relaxation effects are crucial for the interpretation of the results.
Fil: Murgida, Gustavo Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Investigaciones y Aplicaciones no Nucleares. Gerencia de Física (Centro Atómico Constituyentes); Argentina
Fil: Ferrari, Valeria Paola. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Investigaciones y Aplicaciones no Nucleares. Gerencia de Física (Centro Atómico Constituyentes); Argentina
Fil: Ganduglia Pirovano, Maria Veronica. Consejo Superior de Investigaciones Científicas; España
Fil: Llois, Ana Maria. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Investigaciones y Aplicaciones no Nucleares. Gerencia de Física (Centro Atómico Constituyentes); Argentina - Materia
-
Ceria
Oxygen Vacancies
Charge Localization
Phase Stability - Nivel de accesibilidad
- acceso abierto
- Condiciones de uso
- https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
- Repositorio
- Institución
- Consejo Nacional de Investigaciones Científicas y Técnicas
- OAI Identificador
- oai:ri.conicet.gov.ar:11336/35955
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Ordering of oxygen vacancies and excess charge localization in bulk ceria: A DFT+U studyMurgida, Gustavo EzequielFerrari, Valeria PaolaGanduglia Pirovano, Maria VeronicaLlois, Ana MariaCeriaOxygen VacanciesCharge LocalizationPhase Stabilityhttps://purl.org/becyt/ford/1.3https://purl.org/becyt/ford/1The importance of ceria (CeO2) in many applications originates from the ease of oxygen vacancy formation and healing. The ordering of vacancies and the whereabouts of the excess charge in bulk CeO2 are of no less significance than at ceria surfaces, but they have not received the same attention. In this work, the formation of neutral oxygen vacancies in bulk CeO2 is investigated using density-functional theory (DFT) in the DFT + U (U is an effective onsite Coulomb interaction parameter) approach for a broad range of vacancy concentrations Θ (1/64 ≤ Θ ≤ 1/4 ). We find that the excess charge prefers to be localized in cation sites such that the mean Ce3+ coordination number is maximized, and if nearest-neighbor cation sites are reduced, they rather be nonuniformly distributed. Furthermore, we show that a vacancy repels other vacancies from its nearest-neighbor shell and that the [110] and [111] directions are possible directions for clustering of second- and third-neighbor vacancies, respectively. Vacancies prefer not to share cations. The results are discussed in a simple physical picture which enables the separation of the different contributions to the averaged vacancy formation energy. We also consider cells with fluorite structure and same stoichiometries as in existing bulk phases, i.e., Ce11O20 (Θ = 1/11), Ce7 O12 (Θ = 1/7), and Ce2O3 (Θ = 1/4), as well as the corresponding real structures. We find that the vacancy ordering and the location of the excess electrons are consistent with the results for single-phase reduced CeO2, but the Ce11O20, Ce7O12, and Ce2O3 structures are substantially more stable. The stability of these phases as a function of pressure and temperature is discussed. Vacancy-induced lattice relaxation effects are crucial for the interpretation of the results.Fil: Murgida, Gustavo Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Investigaciones y Aplicaciones no Nucleares. Gerencia de Física (Centro Atómico Constituyentes); ArgentinaFil: Ferrari, Valeria Paola. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Investigaciones y Aplicaciones no Nucleares. Gerencia de Física (Centro Atómico Constituyentes); ArgentinaFil: Ganduglia Pirovano, Maria Veronica. Consejo Superior de Investigaciones Científicas; EspañaFil: Llois, Ana Maria. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Investigaciones y Aplicaciones no Nucleares. Gerencia de Física (Centro Atómico Constituyentes); ArgentinaAmerican Physical Society2014-09info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionhttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfapplication/pdfapplication/pdfapplication/pdfhttp://hdl.handle.net/11336/35955Murgida, Gustavo Ezequiel; Ferrari, Valeria Paola; Ganduglia Pirovano, Maria Veronica; Llois, Ana Maria; Ordering of oxygen vacancies and excess charge localization in bulk ceria: A DFT+U study; American Physical Society; Physical Review B: Condensed Matter and Materials Physics; 90; 11; 9-2014; 1-121098-0121CONICET DigitalCONICETenginfo:eu-repo/semantics/altIdentifier/url/https://journals.aps.org/prb/abstract/10.1103/PhysRevB.90.115120info:eu-repo/semantics/altIdentifier/doi/10.1103/PhysRevB.90.115120info:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by-nc-sa/2.5/ar/reponame:CONICET Digital (CONICET)instname:Consejo Nacional de Investigaciones Científicas y Técnicas2025-09-03T09:50:54Zoai:ri.conicet.gov.ar:11336/35955instacron:CONICETInstitucionalhttp://ri.conicet.gov.ar/Organismo científico-tecnológicoNo correspondehttp://ri.conicet.gov.ar/oai/requestdasensio@conicet.gov.ar; lcarlino@conicet.gov.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:34982025-09-03 09:50:54.429CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicasfalse |
dc.title.none.fl_str_mv |
Ordering of oxygen vacancies and excess charge localization in bulk ceria: A DFT+U study |
title |
Ordering of oxygen vacancies and excess charge localization in bulk ceria: A DFT+U study |
spellingShingle |
Ordering of oxygen vacancies and excess charge localization in bulk ceria: A DFT+U study Murgida, Gustavo Ezequiel Ceria Oxygen Vacancies Charge Localization Phase Stability |
title_short |
Ordering of oxygen vacancies and excess charge localization in bulk ceria: A DFT+U study |
title_full |
Ordering of oxygen vacancies and excess charge localization in bulk ceria: A DFT+U study |
title_fullStr |
Ordering of oxygen vacancies and excess charge localization in bulk ceria: A DFT+U study |
title_full_unstemmed |
Ordering of oxygen vacancies and excess charge localization in bulk ceria: A DFT+U study |
title_sort |
Ordering of oxygen vacancies and excess charge localization in bulk ceria: A DFT+U study |
dc.creator.none.fl_str_mv |
Murgida, Gustavo Ezequiel Ferrari, Valeria Paola Ganduglia Pirovano, Maria Veronica Llois, Ana Maria |
author |
Murgida, Gustavo Ezequiel |
author_facet |
Murgida, Gustavo Ezequiel Ferrari, Valeria Paola Ganduglia Pirovano, Maria Veronica Llois, Ana Maria |
author_role |
author |
author2 |
Ferrari, Valeria Paola Ganduglia Pirovano, Maria Veronica Llois, Ana Maria |
author2_role |
author author author |
dc.subject.none.fl_str_mv |
Ceria Oxygen Vacancies Charge Localization Phase Stability |
topic |
Ceria Oxygen Vacancies Charge Localization Phase Stability |
purl_subject.fl_str_mv |
https://purl.org/becyt/ford/1.3 https://purl.org/becyt/ford/1 |
dc.description.none.fl_txt_mv |
The importance of ceria (CeO2) in many applications originates from the ease of oxygen vacancy formation and healing. The ordering of vacancies and the whereabouts of the excess charge in bulk CeO2 are of no less significance than at ceria surfaces, but they have not received the same attention. In this work, the formation of neutral oxygen vacancies in bulk CeO2 is investigated using density-functional theory (DFT) in the DFT + U (U is an effective onsite Coulomb interaction parameter) approach for a broad range of vacancy concentrations Θ (1/64 ≤ Θ ≤ 1/4 ). We find that the excess charge prefers to be localized in cation sites such that the mean Ce3+ coordination number is maximized, and if nearest-neighbor cation sites are reduced, they rather be nonuniformly distributed. Furthermore, we show that a vacancy repels other vacancies from its nearest-neighbor shell and that the [110] and [111] directions are possible directions for clustering of second- and third-neighbor vacancies, respectively. Vacancies prefer not to share cations. The results are discussed in a simple physical picture which enables the separation of the different contributions to the averaged vacancy formation energy. We also consider cells with fluorite structure and same stoichiometries as in existing bulk phases, i.e., Ce11O20 (Θ = 1/11), Ce7 O12 (Θ = 1/7), and Ce2O3 (Θ = 1/4), as well as the corresponding real structures. We find that the vacancy ordering and the location of the excess electrons are consistent with the results for single-phase reduced CeO2, but the Ce11O20, Ce7O12, and Ce2O3 structures are substantially more stable. The stability of these phases as a function of pressure and temperature is discussed. Vacancy-induced lattice relaxation effects are crucial for the interpretation of the results. Fil: Murgida, Gustavo Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Investigaciones y Aplicaciones no Nucleares. Gerencia de Física (Centro Atómico Constituyentes); Argentina Fil: Ferrari, Valeria Paola. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Investigaciones y Aplicaciones no Nucleares. Gerencia de Física (Centro Atómico Constituyentes); Argentina Fil: Ganduglia Pirovano, Maria Veronica. Consejo Superior de Investigaciones Científicas; España Fil: Llois, Ana Maria. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Investigaciones y Aplicaciones no Nucleares. Gerencia de Física (Centro Atómico Constituyentes); Argentina |
description |
The importance of ceria (CeO2) in many applications originates from the ease of oxygen vacancy formation and healing. The ordering of vacancies and the whereabouts of the excess charge in bulk CeO2 are of no less significance than at ceria surfaces, but they have not received the same attention. In this work, the formation of neutral oxygen vacancies in bulk CeO2 is investigated using density-functional theory (DFT) in the DFT + U (U is an effective onsite Coulomb interaction parameter) approach for a broad range of vacancy concentrations Θ (1/64 ≤ Θ ≤ 1/4 ). We find that the excess charge prefers to be localized in cation sites such that the mean Ce3+ coordination number is maximized, and if nearest-neighbor cation sites are reduced, they rather be nonuniformly distributed. Furthermore, we show that a vacancy repels other vacancies from its nearest-neighbor shell and that the [110] and [111] directions are possible directions for clustering of second- and third-neighbor vacancies, respectively. Vacancies prefer not to share cations. The results are discussed in a simple physical picture which enables the separation of the different contributions to the averaged vacancy formation energy. We also consider cells with fluorite structure and same stoichiometries as in existing bulk phases, i.e., Ce11O20 (Θ = 1/11), Ce7 O12 (Θ = 1/7), and Ce2O3 (Θ = 1/4), as well as the corresponding real structures. We find that the vacancy ordering and the location of the excess electrons are consistent with the results for single-phase reduced CeO2, but the Ce11O20, Ce7O12, and Ce2O3 structures are substantially more stable. The stability of these phases as a function of pressure and temperature is discussed. Vacancy-induced lattice relaxation effects are crucial for the interpretation of the results. |
publishDate |
2014 |
dc.date.none.fl_str_mv |
2014-09 |
dc.type.none.fl_str_mv |
info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion http://purl.org/coar/resource_type/c_6501 info:ar-repo/semantics/articulo |
format |
article |
status_str |
publishedVersion |
dc.identifier.none.fl_str_mv |
http://hdl.handle.net/11336/35955 Murgida, Gustavo Ezequiel; Ferrari, Valeria Paola; Ganduglia Pirovano, Maria Veronica; Llois, Ana Maria; Ordering of oxygen vacancies and excess charge localization in bulk ceria: A DFT+U study; American Physical Society; Physical Review B: Condensed Matter and Materials Physics; 90; 11; 9-2014; 1-12 1098-0121 CONICET Digital CONICET |
url |
http://hdl.handle.net/11336/35955 |
identifier_str_mv |
Murgida, Gustavo Ezequiel; Ferrari, Valeria Paola; Ganduglia Pirovano, Maria Veronica; Llois, Ana Maria; Ordering of oxygen vacancies and excess charge localization in bulk ceria: A DFT+U study; American Physical Society; Physical Review B: Condensed Matter and Materials Physics; 90; 11; 9-2014; 1-12 1098-0121 CONICET Digital CONICET |
dc.language.none.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
info:eu-repo/semantics/altIdentifier/url/https://journals.aps.org/prb/abstract/10.1103/PhysRevB.90.115120 info:eu-repo/semantics/altIdentifier/doi/10.1103/PhysRevB.90.115120 |
dc.rights.none.fl_str_mv |
info:eu-repo/semantics/openAccess https://creativecommons.org/licenses/by-nc-sa/2.5/ar/ |
eu_rights_str_mv |
openAccess |
rights_invalid_str_mv |
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/ |
dc.format.none.fl_str_mv |
application/pdf application/pdf application/pdf application/pdf |
dc.publisher.none.fl_str_mv |
American Physical Society |
publisher.none.fl_str_mv |
American Physical Society |
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reponame:CONICET Digital (CONICET) instname:Consejo Nacional de Investigaciones Científicas y Técnicas |
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Consejo Nacional de Investigaciones Científicas y Técnicas |
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CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicas |
repository.mail.fl_str_mv |
dasensio@conicet.gov.ar; lcarlino@conicet.gov.ar |
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13.13397 |