Dresden 2017 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 39: Oxide and Insulator Surfaces: Structure, Epitaxy and Growth II
O 39.3: Vortrag
Dienstag, 21. März 2017, 14:30–14:45, WIL C107
Influence of Surface Structure on Solid-State Electrochemistry: Oxygen Exchange on SrTiO3(110) Surfaces — •Michele Riva1, Markus Kubicek2, Xianfeng Hao3,4, Stefan Gerhold1, Giada Franceschi1, Michael Schmid1, Herbert Hutter2, Juergen Fleig2, Cesare Franchini3, Bilge Yildiz1,5, and Ulrike Diebold1 — 1IAP, TU Wien — 2CTA, TU Wien, — 3CMS, Universität Wien — 4Dep. Chem. Eng., Yanshan Univ., China — 5Lab for Electrochemical Interfaces, MIT, USA
In solid-state electrochemistry, the efficiency for oxygen incorporation of perovskite oxides is interpreted in terms of the availability of surface oxygen vacancies, or the ease of electron transfer. Intriguingly, none of the standard models considers the role of the surface atomic structure. In the present contribution we show that the latter plays a crucial role in affecting oxygen exchange on SrTiO3. Using a host of surface science techniques (STM, LEED, XPS, etc.) we find that the SrTiO3(110)−(n× 1) and (2× m) surface structures are remarkably stable under realistic conditions for oxygen-exchange reactions. We use two different ion-based spectroscopy techniques to quantify 18O exchange and find that the reactivity of these two structures differs by a factor of three. From DFT calculations and electron spectroscopic measurements we rule out that this difference is due to oxygen vacancies or differences in work function or surface potential. Instead our results reveal that the structure itself can determine the extent of the interaction with molecular oxygen, governing the surface reactivity to oxygen exchange reactions of perovskite oxides.