Regensburg 2016 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 97: Nanostructured Surfaces and Thin Films
O 97.1: Vortrag
Freitag, 11. März 2016, 10:30–10:45, S053
High-quality Ru(0001) thin films by magnetron sputter deposition for ceria inverse model catalysts — •Meikel Wellbrock, Marc Sauerbrey, Jan Höcker, Marco Schowalter, Jon-Olaf Krisponeit, Jens Falta, and Jan Ingo Flege — Institute of Solid State Physics, University of Bremen, Otto-Hahn-Allee, 28359 Bremen
The investigation of model systems in heterogeneous catalysis with surface science methods typically requires the use of single crystal substrates. Offering enhanced experimental flexibility at lower costs, thin films prepared by magnetron sputter deposition, an industrially scalable process, represent an attractive alternative. In this study, high-quality, 80 nm thin Ru(0001) films were sputter-deposited on c-plane sapphire and then employed as substrates for the subsequent growth of cerium oxide for surface catalysis. After thermal treatment, atomic force microscopy (AFM) and low-energy electron microscopy (LEEM) showed the Ru thin films to be atomically flat over several micrometers, superior to commercially available Ru single crystals. Sequentially, ceria was grown by evaporation of metallic Ce in an oxygen ambient at elevated temperature and monitored in situ by LEEM. Contrary to the studies involving single crystal substrates, large, triangular, and smooth CeO2(111) islands were observed to nucleate exclusively at randomly distributed v-shaped surface defects (v-pits), determining their azimuthal orientation. Together with the narrow height distribution as revealed by ex situ AFM, these microparticles represent a well-suited model system for the study of surface chemical reactions over ceria inverse model catalysts.