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O: Fachverband Oberflächenphysik
O 44: Poster Session II (Semiconductors; Oxides and Insulators: Adsorption, Clean Surfaces, Epitaxy and Growth; Surface Chemical Reactions and Heterogeneous Catalysis; Surface or Interface Magnetism; Solid-Liquid Interfaces; Organic, Polymeric, Biomolecular Films; Particles and Clusters; Methods: Atomic and Electronic Structure; Time-resolved Spectroscopies)
O 44.32: Poster
Mittwoch, 28. März 2007, 17:00–19:30, Poster C
CO oxidation and partial oxidation of light alkanes over TiO2 supported gold catalysts in microreactors — •Guido Walther1, Sebastian Horch1, Ulrich Quaade2, Ib Chorkendorff2, Søren Jensen3, and Ole Hansen3 — 1CAMD, Department of Physics, DTU, DK-2800 Kgs. Lyngby, Denmark — 2CINF, Department of Physics, DTU, DK-2800 Kgs Lyngby, Denmark — 3MIC, Department of Micro and Nanotechnology, DTU, DK-2800 Kgs Lyngby, Denmark
In a new setup, based on microfabricated silicon reactors, oxidation reaction over TiO2 supported gold catalysts have been studied. In a first experiment size selected gold nanoclusters have been deposited into the microreactor using a cluster source. Here single charge gold clusters were mass selected by a QMS. The cluster beam was focused on the reactor bed using an einzel lens. Hence CO and oxygen were applied at a total flow rate of 0.1 ml min−1, the amount of produced CO2 was still below the detection limit of the used gas chromatograph. An increased amount of catalyst has been realized in a second experiment. Here a powder catalyst, based on TiO2 supported 3.5 nm Au particles, was used. Appropriate measurements to CO oxidation gave rise to study partial oxidation of light alkanes over those catalysts. To investigate the reaction products the microreactor was interfaced to a gas chromatograph and a mass spectrometer, as well. Since methane reacts with oxygen in a stoichiometric ratio 1:2, water will be detected associated with CO2. A significant increase in hydrogen signal marks the onset of the partial oxidation of methane.