Insight of DFT and atomistic thermodynamics on the adsorption and insertion of halides onto the hydroxylated NiO(1 1 1) surface

• Published in: Corrosion science Vol. 52; no. 8; pp. 2643 - 2652
• Main Authors: Bouzoubaa, A., Costa, D., Diawara, B., Audiffren, N., Marcus, P.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.08.2010; Elsevier
• Subjects: A. Nickel; Applied sciences; B. Modelling studies; C. Passive film; Corrosion; Corrosion environments; Exact sciences and technology; Halides; Insertion; Mathematical models; Metals. Metallurgy; Nickel; Phase diagrams; Solvent effect; Surface chemistry; Thermodynamics; A. Nickel; C. Passive film; B. Modelling studies; Thermodynamics; Adsorption; Corrosion; Halides; Surface layer; Modeling; Passivity; Passivation
• ISSN: 0010-938X; 1879-0496
• DOI: 10.1016/j.corsci.2010.04.014

Spin polarized, DFT + U periodic calculations have been used to study the interaction of halides (X) with a (1 × 1)-hydroxylated NiO(1 1 1) surface, a model of passivated nickel. The exchange of surface OH groups by the X ions and the insertion of the halides in the anionic sub-surface layer have been investigated. The substitution of OH by halides is favored by a smaller size of the halide ions and by a lower substitution proportion. An atomistic thermodynamic approach including solvent effects allows us to construct phase diagrams of the surface terminations as a function of the Cl and F concentrations in the aqueous solution. The higher proportion of OH substitution by F, and the lower insertion energy, as compared to Cl, may be related to stronger corrosion caused by F as compared to Cl.