ensity functional calculations are carried out to investigate the interaction of water with the low-index stoichiometric surfaces of the TiO2-B polymorph of titanium dioxide. Dissociative adsorption is predicted for the (100) surface, whereas mixed dissociative/molecular adsorption is favored on both the (010) and (110) surfaces. On the (001) surface, water is able to stabilize the type-II termination, which is metastable in a dry environment, by converting the oxo ions into hydroxyls. At high temperature, water desorption is likely to convert the hydroxylated type-II surface to a type-I termination, whereas the reverse type-I → type-II transition is not allowed when re-adsorption occurs. This could explain the experimental observation that surface hydroxyls on TiO2-B surfaces are not fully regenerated upon successive heating and cooling cycles.

Hydroxylation of TiO2-B: Insights from Density Functional Calculations

CASARIN, MAURIZIO;
2010

Abstract

ensity functional calculations are carried out to investigate the interaction of water with the low-index stoichiometric surfaces of the TiO2-B polymorph of titanium dioxide. Dissociative adsorption is predicted for the (100) surface, whereas mixed dissociative/molecular adsorption is favored on both the (010) and (110) surfaces. On the (001) surface, water is able to stabilize the type-II termination, which is metastable in a dry environment, by converting the oxo ions into hydroxyls. At high temperature, water desorption is likely to convert the hydroxylated type-II surface to a type-I termination, whereas the reverse type-I → type-II transition is not allowed when re-adsorption occurs. This could explain the experimental observation that surface hydroxyls on TiO2-B surfaces are not fully regenerated upon successive heating and cooling cycles.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11577/2423685
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