Berlin 2015 – scientific programme
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O: Fachverband Oberflächenphysik
O 82: Nanostructure at Surfaces: Dots and Clusters
O 82.6: Talk
Thursday, March 19, 2015, 11:45–12:00, MA 043
Activation Energies for Chemical Reactions of size-selected Cobalt Oxide Clusters determined by Electron Diffraction — •Stephan Bartling, Ingo Barke, and Karl-Heinz Meiwes-Broer — University of Rostock, Institute of Physics, 18051 Rostock, Germany
Size-selected cobalt oxide clusters deposited on different substrates can act as selective and efficient nanocatalysts [1]. In this contribution we present a new setup for determination of kinetic reaction parameters (i.e. apparent activation energy) of metal clusters using reflection high energy electron diffraction (RHEED) under reactive conditions. Soft-landed Co clusters of sizes in the range of 6 to 17 nm are exposed to oxygen or hydrogen and heated during the experiment. The evolution of RHEED patterns reveals significant changes of the particle structure during the treatment (cf. [2]). Analysis of the temperature dependence yields the effective activation energy Ea for CoO oxidation and Co3O4 reduction. The results for different cluster diameters are discussed in view of size dependence and the role of cluster morphology.
[1] E.C. Tyo et al., ACS Catalysis 2 (11), 2409 (2012)
[2] A. Kleibert, Phys. Status Solidi B 247, 1048 (2010)