The formation of an oxygen vacancy and the simultaneous re-adsorption of an oxygen atom on regular and low-coordinated (LC) sites (edges and corners) of the surface of alkaline-earth oxides with cubic rock salt structure, MgO, CaO, SrO, and BaO, has been investigated using DFT cluster model calculations. The process corresponds to the formation of a surface Frenkel defect when the vacancy formation energy is partially compensated by the energy gained in the formation of a peroxo group. The structural and electronic properties of vacancies and peroxo groups along the series of alkaline-earth oxides have been analyzed. We found that the role of low-coordinated sites on the surface chemistry of alkaline-earth oxides is of crucial importance for MgO, but decreases for the heavier members. For instance, on BaO the formation of a peroxo group is practically site-insensitive. This is not the case of the vacancy formation, which is always favored on the low-coordinated sites. (c) 2006 Elsevier B.V. All rights reserved.

DI VALENTIN, C., Ferullo, R., Binda, R., Pacchioni, G. (2006). Oxygen vacancies and peroxo groups on regular and low-coordinated sites of MgO, CaO, SrO, and BaO surfaces. SURFACE SCIENCE, 600(5), 1147-1154 [10.1016/j.susc.2006.01.009].

Oxygen vacancies and peroxo groups on regular and low-coordinated sites of MgO, CaO, SrO, and BaO surfaces

DI VALENTIN, CRISTIANA;PACCHIONI, GIANFRANCO
2006

Abstract

The formation of an oxygen vacancy and the simultaneous re-adsorption of an oxygen atom on regular and low-coordinated (LC) sites (edges and corners) of the surface of alkaline-earth oxides with cubic rock salt structure, MgO, CaO, SrO, and BaO, has been investigated using DFT cluster model calculations. The process corresponds to the formation of a surface Frenkel defect when the vacancy formation energy is partially compensated by the energy gained in the formation of a peroxo group. The structural and electronic properties of vacancies and peroxo groups along the series of alkaline-earth oxides have been analyzed. We found that the role of low-coordinated sites on the surface chemistry of alkaline-earth oxides is of crucial importance for MgO, but decreases for the heavier members. For instance, on BaO the formation of a peroxo group is practically site-insensitive. This is not the case of the vacancy formation, which is always favored on the low-coordinated sites. (c) 2006 Elsevier B.V. All rights reserved.
Articolo in rivista - Articolo scientifico
oxide surfaces, DFT
English
2006
600
5
1147
1154
none
DI VALENTIN, C., Ferullo, R., Binda, R., Pacchioni, G. (2006). Oxygen vacancies and peroxo groups on regular and low-coordinated sites of MgO, CaO, SrO, and BaO surfaces. SURFACE SCIENCE, 600(5), 1147-1154 [10.1016/j.susc.2006.01.009].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/45255
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