Preparation of Stoichiometric TiO2(110)-(1x1) Surface.
EMSL Project ID
30193
Abstract
Driving force for investigations of single-crystalline TiO2 surfaces is the wide range of its applications from photocatalysis to degradation of organic pollutants. Rutile TiO2 (110) surface is a preferred system foe experimental studies because it is the most stable rutile surface and also most studied by many experimental techniques, making it a "model" system. Our objective is two-fold: 1) test an "know-how" idea how to prepare not reduced (stoichiometric) TiO2(110)-(1x1) surface by cleaving of commercially available TiO2 crystals under the UHV conditions. Having succeeded with TiO2 in-situ cleaving we would be able to challenge the second goal: 2) by using STM try to detect Ti interstitials which have never been directly observed and which are believed to have a great impact on the physical and chemical properties of the TiO2(110)-(1x1) surface. Addressing the Ti interstitials issue could potentially shed light on the nature of the TiO2(110) surface reconstructions caused by a segregation of Ca - typical contaminant of the TiO2 crystals. Given the propensity of Ca and Ti atoms to substitute each other we would expect to observe decoration of the interstitial sites by Ca atoms.We contemplate that introducing an in-situ prepared stoichiometric TiO2(110)-(1x1) surface would be a great step toward bridging the "material gap" between model and real catalysts because under the catalytically relevant conditions the TiO2 catalyst is usually fully oxidized while in model ultra-high vacuum studies (UHV) the traditional sample preparation procedure based on sputtering/annealing cycling leads to significantly reduced surfaces with a fraction of missing oxygen atoms. As an another approach to control the stoichiometry of the TiO2(110) surface we also propose to explore an effect of an electrical current stress on reduced crystal, which has not been explored before.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2008-08-22
End Date
2009-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members