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O: Fachverband Oberflächenphysik
O 88: Poster Session VII: Oxides and insulators: Adsorption and reaction of small molecules I
O 88.5: Poster
Thursday, March 4, 2021, 10:30–12:30, P
Unravelling CO Adsorption on Model Single-Atom Catalysts (SAC) — Jan Hulva1, •Matthias Meier1,2, Roland Bliem1, Zdenek Jakub1, Florian Kraushofer1, Michael Schmid1, Ulrike Diebold1, Cesare Franchini2,3, and Gareth S. Parkinson1 — 1Institute of Applied Physics, TU Wien, Vienna, Austria — 2Computational Materials Physics, University of Vienna, Vienna, Austria — 3Alma Mater Studiorum, Universitá di Bologna, Bologna, Italy
The electronic structure of a surface atom is crucial when it comes to predicting and understanding its binding to adsorbates. This has been demonstrated in depth on metal surfaces, where the d-band center of mass and d-band filling are two of the main descriptors when its comes to defining the adsorption of small molecules. We propose an extension of this model towards oxide surfaces and SACs, based on a combination of density functional theory (DFT) and surface sensitive techniques (Hulva et al, Science (in press)). The same rules regarding the electronic structure of the binding atom apply and govern the adsorption energies. But additionally, the exact local environment, affecting the electronic states, also leads to two particular deviations. Firstly, if the surface atom is saturated in ligands, no matter the electronic structure, the atom will bind CO poorly, and therefore the metal will be almost inert. On the other hand, if the coordination of the metal atom at the surface is low and the CO adsorption geometry is not ideal, CO-induced relaxations occur. This can lead to strong offsets with respect to the adsorption energy estimated by the electronic structure alone.