Dresden 2017 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 31: Oxide and Insulator Surfaces: Structure, Epitaxy and Growth I
O 31.5: Vortrag
Dienstag, 21. März 2017, 11:30–11:45, WIL C107
Probing the surface structure of thin TiOx films on Pt3Ti(111) by IRRAS and XPS — •Ludger Schöttner1, Marco Moors2, Fabian Bebensee1, Xiaojuan Yu1, Alexei Nefedov1, Yuemin Wang1, and Christof Wöll1 — 1Institute of Functional Interfaces, Karlsruhe Institute of Technology, 76344 Eggenstein-Leopoldshafen, Germany — 2Peter Grünberg Institute, Forschungszentrum Jülich, Wilhelm-Johnen-Straße, 52425 Jülich, Germany
A fundamental understanding of bimetallic catalysts is of great interest because of their important applications in clean energy production. Here we present a thorough study of the structure evolution of TiOx thin films on Pt3Ti(111) monitored by IRRAS with CO as probing molecule in conjunction with XPS and LEED analysis. The results demonstrate consistently the formation of different oxide phases on Pt3Ti(111) including z‘-TiOx, w‘-TiOx, z-TiOx and rect-TiO2, which vary depending on the substrate temperature and the amount of dosed O2. The pure Pt3Ti(111) surface is terminated by Pt atoms as confirmed by the IR band at 2087 cm−1 for Pt-bonded on-top CO. During oxidation at elevated temperatures, TiOx thin film growth was resolved by the observation of an additional CO band at 2100 cm−1 in the initial state. For the z‘-TiOx structure, no any CO vibrations are detected, revealing the formation of a closed oxide layer with oxygen termination. The thickness of various TiOx thin films is estimated by a quantitative XPS analysis. The structure evolution of TiOx thin films will be discussed in detail based on the elaborate IR and XPS results.