Dresden 2017 – scientific programme
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O: Fachverband Oberflächenphysik
O 81: Oxide and Insulator Surfaces: Adsorption II
O 81.8: Talk
Wednesday, March 22, 2017, 17:45–18:00, WIL C107
Adsorption of Oxygen on Ca3Ru2O7(001) — •Daniel Halwidl1, Wernfried Mayr-Schmölzer1,2, Florian Mittendorfer1,2, David Fobes3, Jin Peng3, Zhiqiang Mao3, Michael Schmid1, Josef Redinger1,2, and Ulrike Diebold1 — 1Institute of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10, A-1040 Vienna, Austria — 2Center for Computational Materials Science, TU Wien, Wiedner Hauptstraße 8-10, A-1040 Vienna, Austria — 3Department of Physics and Engineering Physics, Tulane University, New Orleans, LA, USA
Complex ternary perovskite oxides are increasingly used in solid oxide fuel cells and catalysis [1]. Therefore it is highly desirable to obtain a better understanding of their surface chemical properties. We use low-temperature STM, nc-AFM, XPS and DFT to investigate the adsorption of oxygen on the layered perovskite Ca3Ru2O7.
Single oxygen molecules appear fuzzy in STM, but are resolved in nc-AFM at LHe and LN2 temperature. At higher coverages the molecules form a (2 × 1) overlayer that covers almost the whole surface. Local contact potential difference (LCPD) measurements suggest that the oxygen molecules are charged, in agreement with DFT calculations predicting adsorption as superoxo species. Desorption of the O2 occurs at approximately 220 K, again in agreement with the calculated adsorption energy of Eads = 0.7 eV.
This work was supported by the Austrian Science Fund (FWF project F45) and the ERC Advanced Grant “OxideSurfaces”.
[1] M. A. Pena, and J. L. G. Fierro, Chem. Rev. 101, 1981 (2001)