COLL 65 |
| We have used a combination of scanning tunneling microscopy measurements and large scale density functional theory calculations to elucidate the fundamental role and formation process of defects on TiO2 (110) surface. The effect of the presence of the defect on dynamics of chemical reactions on the surface is investigated. Thanks to the interplay between high resolution data and modeling, we have developed a new structural model for surface reconstructions driven by Ti interstitials on TiO2(110). Ab initio spin polarized molecular dynamics calculations show the dynamics of dissociation of molecular oxygen at the defects. The subsequently oxidized Ti interstitials form the edge/face-sharing octahedra, which serve as building blocks for (1x1) reconstruction. Thus, contrary to conventional wisdom, the 1x1 periodicity alone is insufficient to establish the correct surface stoichiometry. In addition, edge/face-sharing octahedra provide a specific, structural and compositional model for the reversible phase transition between (1x1) and (1x2) in which oxidation/reduction is entirely achieved by transfer of the added Ti and O rows. |
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Dynamics of Single Atoms, Molecules and Clusters on Surfaces
2:00 PM-5:00 PM, Sunday, 10 September 2006 Sir Francis Drake -- Renaissance Room, Oral
Division of Colloid & Surface Chemistry |