Theoretical Study Addressing the (Meta-)Stability of Bimetallic Nanostructures

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Based on theoretical studies, this project shall lead to a better understanding of the stability and reactivity of bimetallic nanostructures. In order to alter the properties of bimetallic catalysts, the composition and/or the structure can be modified. However, catalytically active bimetallic structures are often not stable and exhibit degrading. The best bimetallic structure with desired catalytic properties is useless if it is not thermally stable. Catalytically active structures do not necessarily need to be thermodynamically stable, they might also be kinetically stabilized. Non-equilibrium methods are hence required to test of occurence of stationary structures. Therefore the stability of bimetallic nanostructures shall be studied by performing kinetic Monte Carlo (kMC) simulations. The activation barriers which are a necessary input for the kMC simulations shall be derived from electronic structure calculations based on density functional theory (DFT). Concentrating on experimentally well-studied model systems, general trends in the stability of bimetallic surface alloys shall be derived.