Patricia Pérez-Bailac^1,2, Pablo G. Lustemberg^1,3*, M. Verónica Ganduglia-Pirovano¹

1 Instituto de Catálisis y Petroleoquímica (ICP-CSIC), C/Marie Curie 2, 28049 Madrid, Spain

2 PhD Programme in Applied Chemistry, Doctoral School, Universidad Autónoma de Madrid, C/Francisco Tomás y Valiente 2, 28049 Ciudad Universitaria de Cantoblanco, Madrid, Spain

3 Instituto de Física Rosario (IFIR-CONICET) and Universidad Nacional de Rosario (UNR), Ocampo y Esmeralda, S2000EKF Rosario, Santa Fe, Argentina

* Corresponding authors emails: p.lustemberg@csic.es

DOI10.24435/materialscloud:ax-hy [version v1]

Publication date: Aug 31, 2021

How to cite this record

Patricia Pérez-Bailac, Pablo G. Lustemberg, M. Verónica Ganduglia-Pirovano, Facet-dependent stability of near-surface oxygen vacancies and excess charge localization at CeO2 surfaces, Materials Cloud Archive 2021.142 (2021), doi: 10.24435/materialscloud:ax-hy.

Description

To study the dependence of the relative stability of surface (VA) and subsurface (VB) oxygen vacancies with the crystal facet of CeO2, the reduced (100), (110) and (111) surfaces, with two different concentrations of vacancies, were investigated by means of density functional theory (DFT+U) calculations. The results show that the trend in the near-surface vacancy formation energies for comparable vacancy spacings, i.e. (110) < (100) < (111), does not follow that in the surface stability of the facets, i.e. (111) < (110) < (100). The results also revealed that the preference of vacancies for surface or subsurface sites, as well as the preferred location of the associated Ce3+ polarons, are facet and concentration dependent. At the higher vacancy concentration, the VA is more stable than the VB at the (110) facet whereas at the (111), it is the other way around, and at the (100) facet, both the VA and the VB have similar stability. The stability of the VA vacancies, compared to that of the VB, is accentuated as the concentration decreases. Nearest neighbor polarons to the vacant sites are only observed for the less densely packed (110) and (100) facets. These findings are rationalized in terms of the packing density of the facets, the lattice relaxation effects induced by vacancy formation and the localization of the excess charge, and the repulsive Ce3+ - Ce3+ interactions.

Materials Cloud sections using this data

Files

File name	Size	Description
README.txt MD5md5:98a649226e8b1297ddd9dd9582bb490a	1.4 KiB	Description of the uploaded data
111.tar.gz MD5md5:8d0786fd55a2515cf2bc1b757fec5177	1.2 MiB	DFT calculations of (111) CeO2 surface 2x2 and 3x3 cells
110.tar.gz MD5md5:012d2d643d4ad2147dfa0e4c66fda21c	10.3 MiB	DFT calculations of (110) CeO2 surface 2x2 and 4x2 cells
100.tar.gz MD5md5:cb1436b03ecb251c942bf7f4c5321851	23.7 MiB	DFT calculations of (100) CeO2 surface p(2x2) and c(2x2) cells

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Keywords

cerium oxide surfaces facet-dependent stability oxygen vacancies lattice relaxations excess charge localization