Regensburg 2016 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 40: Heterogeneous Catalysis: Experiment
O 40.3: Vortrag
Dienstag, 8. März 2016, 14:30–14:45, S053
Surface oxide on Pt(111) as the active phase for NO and CO oxidation — •Matthijs van Spronsen1, Joost Frenken1, and Irene Groot2 — 1Huygens-Kamerlingh Onnes Laboratory, Leiden University, Leiden, The Netherlands — 2Gorlaeus Laboratories, Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
Pt find its main application in the automotive industry as a catalytic converter. As catalyst, Pt transforms harmful exhaust gases to more environment-friendly components. Technical catalysts are complex and is often obscuring fundamental processes. Therefore, model catalysts are frequently used. The simplest model catalyst is the close-packed (111) surface. Even though this model catalyst has been studied for over 45 years, the main questions remain unsolved. How does Pt oxidize? What is the atomic structures of the oxide(s)? And are the structures stable under chemical reaction conditions?
We studied the oxidation of Pt(111) with the ReactorSTM, which is an STM integrated with a small flow reactor. It allows to study the atomic structure of surfaces under chemical reaction conditions (high p & T).
This resulted in the observation of two novel structures, which were identified as single-layer thick surface oxides. The first one consisted of triangles forming spoked wheels, while the second one was a lifted-row oxide. Both structures were also observed under NO oxidation reaction conditions. These oxides contain weakly-bound oxygen atoms, which should be very reactive.