Regensburg 2010 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 41: Poster Session I (Semiconductor Substrates: Epitaxy and growth; Semiconductor Substrates: Adsorbtion; Semiconductor Substrates: Solid-liquid interfaces; Semiconductor Substrates: Clean surfaces; Oxides and insulators: Epitaxy and growth; Oxides and insulators: Adsorption; Oxides and insulators: Clean surfaces; Organic, polymeric and biomolecular films - also with adsorbates; Organic electronics and photovoltaics, Surface chemical reactions; Heterogeneous catalysis; Phase transitions; Particles and clusters; Surface dynamics; Surface or interface magnetism; Electron and spin dynamics; Spin-Orbit Interaction at Surfaces; Electronic structure; Nanotribology; Solid/liquid interfaces; Graphene; Others)
O 41.53: Poster
Dienstag, 23. März 2010, 18:30–21:00, Poster B1
Methanol oxidation over ZnO and Au/ZnO nanoparticles studied by vibrational spectroscopy — •Heshmat Noei1, Martin Muhler1, and Yuemin Wang1,2 — 1Lehrstuhl für Technische Chemie, Ruhr-Universität Bochum, D-44780 Bochum, Germany — 2Lehrstuhl für Physikalische Chemie I, Ruhr-Universität Bochum, 44801 Bochum, Germany
Zinc oxide is one of the most studied materials due to its electrical, optical and catalytical properties and potential applications. The interaction of methanol with zinc oxide is a topic of fundamental and applied interest. In this work we report on the adsorption and oxidation of methanol over ZnO nanoparticles at a wide range of temperatures by employing a newly designed ultra-high vacuum infrared spectroscopy (UHV-FTIRS). Exposing the clean ZnO nanopowders to methanol at 110 K leads to the molecular adsorption, whereas at 300 K methanol is adsorbed dissociatively giving methoxy species. The FTIRS data further indicate the formation of two different methoxy species which are bound to the polar ZnO(000-1) and nonpolar ZnO(10-10) surfaces, respectively. During heating to higher temperatures, methoxy reacts partially with surface oxygen yielding formate species as confirmed by the appearance of formate-related IR bands. In addition, we could identify two different formate species, which are formed on ZnO(000-1) and ZnO(10-10) surfaces, respectively. Upon heating to 600 K, both formate species are decomposed completely. We have further studied methanol oxidation over Au/ZnO nanopartcles. The corresponding reaction mechanisms will be discussed in details.