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O: Fachverband Oberflächenphysik

O 17: Adsorption on Metal Surfaces

O 17.11: Vortrag

Montag, 7. März 2016, 17:30–17:45, H6

Chemo-mechanical coupling from first principles: On the strain dependency of oxygen adsorption on Pd(111) — •Gregor Feldbauer, Anja Michl, and Stefan Müller — Hamburg University of Technology, Institute of Advanced Ceramics, Denickestr. 15, D-21073 Hamburg

Mechanical deformation can affect the adsorption and reaction processes of reactants on surfaces. Thus, by straining catalytically active surfaces their reactivity as well as selectivity can be influenced, which is of high importance in the field of heterogeneous catalysis.

Here, the adsorption of atomic oxygen on Pd(111) is used as a model system. At first, the dependence of the adsorption energetics on various oxygen adsorption sites and coverages is investigated within the framework of density functional theory (DFT). Furthermore, vibrational frequencies, work functions and densities of states are studied. Using the DFT results as input data a cluster-expansion Hamiltonian is constructed to scan exhaustively the configuration space of the examined model system. This allows to identify the most favourable adsorption configurations. Additionally, for various configurations biaxial strain is applied in the surface plane to obtain the response of the adsorption energetics. Particularly, the coupling parameter between the strain and adsorption energies is of interest to allow for a comparison with experiments.