Senior researcher Stefan Wendt, Interdisciplinary Nanoscience Center, Aarhus University, Aarhus, Denmark

Reactions on the Rutile TiO2(110) Surface Studied by High-Resolution STM and TPD

In this lecture, I will summarize surface science studies addressing a prototypical model oxide system – the rutile TiO₂(110)–(1 × 1) surface. The identification of point defects on the terraces such as oxygen vacancies, hydroxyl groups, and near surface defect such as Ti interstitials will be discussed. Using high-resolution scanning tunnelling microscopy (STM) several examples for the reaction of water and ethanol molecules with oxygen vacancies will be presented [1]. These reactions have been directly imaged in so-called STM movies. Whereas the reactions on the terraces can be imaged directly, a combination of static STM results with temperature-programmed desorption/reaction (TPD/TPR) measurements has been utilized to study the reactions at step edges, with the focus particularly on the <1-11> step edges [2]. In addition, I will address the complex oxygen–TiO₂(110) interaction, which is related to processes occurring on the terraces and in the bulk [3,4]. Finally, I will compare the photo-reaction of ethanol on differently prepared TiO₂(110) surfaces.

[1] J. Ø. Hansen, P. Huo, U. Martinez, E. Lira, Y.Y. Wei, R. Streber, E. Lægsgaard, B. Hammer, S. Wendt, F. Besenbacher, Phys. Rev. Lett. 107, 136102 (2011).

[2] U. Martinez, J. Ø. Hansen, E. Lira, H. H. Kristoffersen, P. Huo, R. Bechstein, E. Lægsgaard, F. Besenbacher, B. Hammer, S. Wendt, Phys. Rev. Lett. 109, 155501 (2012).

[3] S. Wendt, P. T. Sprunger, E. Lira, G. K. H. Madsen, Z. Li, J. Ø. Hansen, J. Matthiesen, A. Blekinge-Rasmussen, E. Lægsgaard, B. Hammer, F. Besenbacher, Science 320, 1755 (2008).

[4] E. Lira, J. Ø. Hansen, P. Huo, R. Bechstein, P. Galliker, E. Lægsgaard, B. Hammer, S. Wendt, F. Besenbacher, Surf. Sci. 604, 1945 (2010).

Host: Director & professor Jørgen Kjems, iNANO & Department of Molecular Biology and Genetics