Relative Stability of Near-Surface Oxygen Vacancies at the CeO2 (111) Surface upon Zirconium Doping
- Departamento de Física, Universidad Nacional del Sur and Instituto de Física del Sur (IFISUR), CONICET, Av. L.N. Alem 1253, B8000CPB, Bahía Blanca, Buenos Aires, Argentina
- Instituto de Física Rosario (IFIR-CONICET), Ocampo y Esmeralda, S2000EKF Rosario, Santa Fe, Argentina
- Instituto de Catálisis y Petroleoquímica (ICP-CSIC), C/Marie Curie 2, 28049 Madrid, Spain
DOI10.24435/materialscloud:2019.0082/v2 (version v2, submitted on 12 December 2019)
How to cite this entry
Guadalupe S. Otero, Pablo G. Lustemberg, Fernando Prado, M. Veronica Ganduglia-Pirovano, Relative Stability of Near-Surface Oxygen Vacancies at the CeO2 (111) Surface upon Zirconium Doping, Materials Cloud Archive (2019), doi: 10.24435/materialscloud:2019.0082/v2.
The effects of Zr doping on the stability of the CeO2(111) surface as a function of the dopant concentration and distribution, as well as on the relative stability of surface and subsurface oxygen vacancies, were studied by means of density functional theory (DFT+U) calculations. For a given Zr content, the more stable structures do not correspond to those configurations with Zr located in the topmost O-Ce-O trilayer (TL1), but in inner layers, and the stability decreases with increasing Zr concentration. For the undoped CeO2(111) surface, the preference of subsurface vacancies with next-nearest neighbor (NNN) Ce3+ configuration has earlier been predicted. For the Zr-doped surface, the formation of vacancies was studied using a surface unit cell with 2x2 periodicity, and it was found that the most stable configuration corresponds to the Zr atom located in the surface layer (TL1) neighboring a subsurface oxygen vacancy with NNN Ce3+, being the formation energy equal to 1.16 eV. The corresponding surface oxygen vacancy is 0.16 eV less stable. These values are by 0.73 and 0.92 eV, respectively, smaller than the corresponding ones for the pure CeO2(111) surface. Moreover, when Zr is located in TL2 the subsurface vacancy becomes by 0.10 eV less stable, compared to Zr in the TL1. The Ce3+ preference for the next-nearest neighbor cationic sites to both surface and subsurface vacancies at CeO2 (111), becomes more pronounced upon Zr doping. The results are explained in terms of Zr- and vacancy-induced lattice relaxation effects.
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|5.6 MiB||Raw data of Table S4 as presented in the Supporting Information|
|4.9 MiB||Raw data of Table S5 as presented in the Supporting Information|
|14.2 MiB||Raw data of Table S3 as presented in the Supporting Information|
|6.9 MiB||Raw data of Table 1 as presented in the publication|
|30.9 MiB||Raw data of Table S1 as presented in the Supporting Information|
|1.7 MiB||DFT relaxation states corresponding to O2 in gas phase, CeO2 bulk phase, ZrO2 bulk and 1x1, 2x2 and 3x3 CeO2(111).|
|880.7 KiB||DFT relaxation states corresponding to bulks with/without oxygen vacancy: Ce32O64, Ce32O63, Ce31ZrO64 and Ce31ZrO63.|
12 December 2019 [This version]
28 November 2019