Surface cation ratios of binary oxide solid solutions

S. Y. Liu, Harold H Kung

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

The cation ratios in the (100) surface of cubic oxides of bulk composition A0.99B0.01O, in which A and B are divalent cations were calculated using a monolayer model. Divalent cations including Ni, Co, Mn, Fe and Mg were studied. The cations were represented by a shell model, and the surface compositions were calculated by minimizing the total Gibbs free energy of the solid. The bulk energy change on surface segregation was evaluated by minimizing the energy change on substituting one bulk cation by another in an infinitely dilute solid solution and the surface energy was evaluated by a statistical method to accommodate the possibility that both cations can exist at non-negligible densities at the surface. The bulk energy change on surface segregation was found to be dominant in most cases. The surface energy change, the entropy change, and the change in crystal field stabilization energy were all secondary. Thus, except when the difference in ionic radii is very small, the larger cation is always more preferred at the surface. This conclusion appears to be in agreement with available experimental data.

Original languageEnglish
Pages (from-to)504-522
Number of pages19
JournalSurface Science
Volume110
Issue number2
DOIs
Publication statusPublished - Oct 1 1981

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Oxides
Cations
Solid solutions
solid solutions
Positive ions
cations
oxides
Surface segregation
Divalent Cations
Interfacial energy
surface energy
Gibbs free energy
Surface structure
Monolayers
Statistical methods
energy
Entropy
Stabilization
crystal field theory
Crystals

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Condensed Matter Physics
  • Surfaces and Interfaces

Cite this

Surface cation ratios of binary oxide solid solutions. / Liu, S. Y.; Kung, Harold H.

In: Surface Science, Vol. 110, No. 2, 01.10.1981, p. 504-522.

Research output: Contribution to journalArticle

Liu, S. Y. ; Kung, Harold H. / Surface cation ratios of binary oxide solid solutions. In: Surface Science. 1981 ; Vol. 110, No. 2. pp. 504-522.
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