Regensburg 2019 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 29: Nanostructures at Surfaces III: Dots, Particles, and Clusters
O 29.6: Vortrag
Dienstag, 2. April 2019, 11:45–12:00, H25
Understanding charge transfer and electronic polarization of Au nano-catalysts supported on reduced TiO2(110) surfaces — •Su-Hyun Yoo1, Niklas Siemer2, Mira Todorova1, Dominik Marx2, and Jörg Neugebauer1 — 1Department of Computational Materials Design, Max-Planck-Institut für Eisenforschung GmbH, Düsseldorf, Germany — 2Lehrstuhl für Theoretische Chemie, Ruhr Universität Bochum, 44780 Bochum, Germany
Gold nanoparticles on TiO2(110) surfaces containing oxygen vacancies are of great interest due to their catalytic activity respective oxidation reactions, such as the water gas shift reaction, the CO oxidation reaction and others. Despite extensive studies, the nature of the interactions between oxygen vacancy, substrate and the gold nanoparticle remains controversial, which hampers an understanding of the catalytic mechanism. Combining ab-initio molecular dynamics calculations with methods developed in semiconductor physics to study defects, we investigate the interactions between the vacancy and the nanoparticle for a representative set of density-functionals theory (DFT) exchange-correlation functionals (PBE, PBE+U and two hybrid functionals). The obtained band diagrams allow us to discuss the direction of charge transfer between the nanoparticle and the substrate. Despite the differences of the constructed band diagrams from the employed functionals, we consistently find the absence of charge transfer between the vacancy and the cluster, as well as a positive charging of the Au nanoparticle. The obtained results and their implication for the role of the vacancy in the catalytic system will be discussed.