Dresden 2020 – scientific programme
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O: Fachverband Oberflächenphysik
O 109: Heterogeneous Catalysis on Metal Oxides
O 109.2: Talk
Thursday, March 19, 2020, 15:15–15:30, TRE Phy
Adsorption of O2 on the rutile TiO2(110) surface revisited by nc-AFM — •Igor Sokolović1, Michele Reticcioli2, Martin Čalkovský1, Margareta Wagner1, Michael Schmid1, Cesare Franchini2, Ulrike Diebold1, and Martin Setvin1 — 1Institute of Applied Physics, TU Wien, Vienna, Austria — 2Center for Computational Materials Science, Faculty of Physics, University of Vienna, Vienna, Austria
Rutile TiO2(110) surface is extensively studied and it is considered a model transition-metal oxide surface [1]. The adsorption of molecular O2 has been long investigated with various techniques [2], but still even the basic adsorption configurations remain unclear. In this research, we used non-contact atomic force microscopy (nc-AFM) to directly observe the adsorption configurations of molecular O2 dosed at low sample temperatures. We demonstrate that an oxygen-terminated AFM tip provides excellent lateral resolution, and that it does not perturb the adsorbates. Using density functional theory (DFT) we simulated the observed adsorption configurations and determined the charge state of the adsorbed molecules, which is 2- (peroxo) in all cases. We performed experiments of thermal annealing, charge injection/removal, and ultraviolet light irradiation of the O2 covered surface. By directly observing the reactants of such experiments, we explain that the rich behavior of O2 on this surface stems from the differences in the types of the adsorbed molecules, thus answering several long-standing questions. [1] U. Diebold, Surface science reports 48, 53 (2003). [2] J. T. Yates Jr, Surface Science 603, 1605 (2009).