Dresden 2014 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 58: Oxide and Insulator Surfaces II
O 58.2: Vortrag
Mittwoch, 2. April 2014, 16:15–16:30, PHY C 213
High chemical activity of a perovskite surface: Reaction of CO with Sr3Ru2O7 — •Bernhard Stöger1, Marcel Hieckel1, Florian Mittendorfer1, Zhiming Wang1, Michael Schmid1, David Fobes3, Jin Peng3, Raimund Podloucky2, Zhiqiang Mao3, Josef Redinger1, and Ulrike Diebold1 — 1Institute of Applied Physics, Vienna University of Technology, Vienna, Austria — 2Institute for Physical Chemistry, University of Vienna, Vienna, Austria — 3Department of Physics and Engineering Physics, Tulane University, New Orleans, LA, USA
We focus our studies on Sr3Ru2O7, which is the two-layer member of the ruthenate Ruddlesden-Popper series Srn+1RunO3n+1. In-situ cleaving of high-quality single crystals opens up the possibility to investigate a very well defined Sr-O surface layer by low-temperature Scanning Tunneling Microscopy. Exposing Sr3Ru2O7 to CO at 78 K shows that CO adsorbs at regular surface sites above an apical surface O atom with a binding energy, Eads, of 0.6 eV. Above 100 K this physisorbed CO reacts by pushing out the surface O atom, forming a bent CO2 molecule with its C atom bound to the Ru underneath. The resulting species is best described as chemisorbed metal carboxylate (Ru-COO). The low activation energy (0.29 eV) of the process and the high binding energy (Eads = 2.17 eV) of the resulting adsorbate confirm a strong reaction between CO and regular surface sites of Sr3Ru2O7.
This work was supported by the Austrian Science Fund (FWF project F45).