Regensburg 2010 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 58: Surface chemical reactions II

O 58.7: Vortrag

Mittwoch, 24. März 2010, 16:30–16:45, H42

Interaction of methanol with the O-terminated ZnO(000-1) surface — •Lanying Jin, Hengshan Qiu, and Yuemin Wang — Lehrstuhl für Physikalische Chemie I, Ruhr-Universität Bochum, 44801 Bochum, Germany

Zinc oxide has attracted much research interest due to its particular electronic, optical and catalytic properties [1]. In catalysis, Cu/ZnO is the standard heterogeneous catalyst for the industrial methanol synthesis and its stream reforming. Therefore, studies of the interaction of methanol with ZnO are of fundamental importance in understanding the relevant catalytic processes on the atomic scale. In this work, the adsorption of methanol on O-ZnO(000-1) was studied by high resolution electron energy loss spectroscopy (HREELS) and thermal desorption spectroscopy (TDS). The clean, adsorbate-free O-ZnO(000-1) surface is electrostatically unstable and exhibits a (1x3) reconstruction with the presence of abundance of oxygen vacancies. It was found that exposing ZnO(000-1) to methanol at room temperature leads to the dissociative adsorption forming methoxy species at oxygen vacancies. After heating to higher temperatures the adsorbed methoxy species undergo further decomposition at 590 and 660 K releasing CH₂O, H₂, CO, and CO₂. The formation of formate species, which has been observed in methanol oxidation over ZnO powder samples, could be clearly ruled out based on the present results on ZnO(000-1). [1] Ch. Wöll, Prog, Surf. Sci. 82(2007) 55.