Berlin 2018 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 118: Metal substrates: Structure, epitaxy and growth
O 118.6: Vortrag
Freitag, 16. März 2018, 12:15–12:30, MA 005
Temperature dependent growth of Zn and formation/decomposition of ZnOx on Au(111) — •Konstantin M. Schüttler, Albert K. Engstfeld, and R. Jürgen Behm — Institute of Surface Chemistry and Catalysis, Ulm University, D-89069 Ulm
Methanol is a promising molecule for chemical energy storage, e.g., when using H2 from renewable sources for its synthesis. Au/ZnO was found to be a highly active catalyst for the synthesis of "Green Methanol" from CO2/H2 as a "Solar Fuel"[1]. Previously, CuZn alloys have been used as model systems for the industrially used Cu/ZnO catalysts, for which it has been found that under reaction conditions ZnO at the perimeter of the Cu nanoparticles is partly reduced forming bimetallic CuZn sites[2]. For Au/ZnO this approach is similarly plausible. In order to gain more insight into the formation and nature of active sites, the formation, structure, electronic and chemical properties of bimetallic Zn/Au(111) surfaces serving as structurally well-defined 2D model catalysts were studied under UHV conditions. The temperature dependence of the nucleation, growth and alloy formation processes of Zn on Au(111) is discussed, based on STM studies. In addition, the reactivity of Zn surface atoms in the Au/Zn/O system, which may be crucial for the catalytic performance of ZnO supported MeOH synthesis catalysts, was studied by exposing Zn/Au(111) surfaces to molecular and atomic oxygen. Furthermore the deposition of Zn in an oxygen atmosphere and the thermal decomposition of these ZnOx/Au(111) (0≤x≤1) surfaces has been studied.