Publications in Scientific Journals:
H. Over, M. Knapp, E. Lundgren, A.P. Seitsonen, M. Schmid, P. Varga:
"Visualization of Atomic Processes on Ruthenium Dioxide using Scanning Tunneling Microscopy";
The visualization of surface reactions on the atomic scale provides direct insight into the microscopic reaction steps taking
place in a catalytic reaction at a (model) catalyst's surface. Employing the technique of scanning tunneling microscopy (STM), we
have investigated the CO oxidation reaction over the RuO2(110) and RuO2(100) surfaces. For both surfaces the protruding bridging
O atoms are imaged in STM as bright features. The reaction mechanism is identical on both orientations of RuO2. CO molecules
adsorb on the undercoordinated surface Ru atoms from where they recombine with undercoordinated O atoms to form CO2 at the
oxide surface. In contrast to the RuO2(110) surface, the RuO2(100) surface stabilizes also a catalytically inactive c(2x2) surface
phase onto which CO is not able to adsorb above 100 K. We argue that this inactive RuO2(100)-c(2x2) phase may play an important
role in the deactivation of RuO2 catalysts in the electrochemical Cl2 evolution and other heterogeneous reactions.
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Created from the Publication Database of the Vienna University of Technology.