Bulk-defect dependent adsorption on a metal oxide surface: S/TiO2(110)

E. L. D. Hebenstreit, W. Hebenstreit, H. Geisler, C. A. Ventrice Jr., P. T. Sprunger, U. Diebold

Department of Physics, Tulane University, New Orleans, LA 70118, U.S.A.
Institut für Angewandte Physik, TU Wien, 1040 Wien, Austria
Department of Chemistry, Xavier University of Louisiana, New Orleans, LA 70125, U.S.A.
Department of Physics, University of New Orleans, New Orleans, LA 70148, U.S.A.
Center for Advanced Microstructures and Devices (CAMD), Louisiana State University, Baton Rouge, LA, 70806, U.S.A.

Surf. Sci. 486 (2001) L467-L474

The adsorption of molecular sulfur on TiO2(110)(1×1) has been studied with scanning tunneling microscopy and photoelectron spectroscopy. At room temperature S binds dissociatively to 5-fold coordinated Ti atoms and oxygen vacancies. At elevated temperatures (120-440°C) sulfur replaces surface oxygen atoms. Evidence was found that the reduction state of TiO2 crystals strongly affects the surface coverage of S at elevated temperatures. The rate of the O-S site exchange is kinetically limited by the arrival of diffusing bulk defects at the surface.

Corresponding author: Ulrike Diebold (diebold at iap_tuwien_ac_at).

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