Regensburg 2022 – scientific programme

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O: Fachverband Oberflächenphysik

O 70: Supported nanoclusters: Structure, Reactions, Catalysis

O 70.4: Talk

Thursday, September 8, 2022, 16:00–16:15, H6

Tuning SMSI Kinetics on Pt-loaded TiO2(110) by Choosing the Pressure — •Philip Petzoldt¹, Moritz Eder¹, Sonia Mackewicz¹, Monika Blum^2,3, Tim Kratky⁴, Sebastian Günther⁴, Martin Tschurl¹, Ueli Heiz¹, and Barbara Lechner⁵ — ¹Physical Chemistry, Department of Chemistry and Catalysis Research Center, Technical University of Munich — ²Advanced Light Source, Lawrence Berkeley National Laboratory — ³Chemical Sciences Division, Lawrence Berkeley National Laboratory — ⁴Physical Chemistry with Focus on Catalysis, Department of Chemistry and Catalysis Research Center, Technical University of Munich — ⁵Functional Nanomaterials, Department of Chemistry and Catalysis Research Center, Technical University of Munich

The encapsulation of noble metal particles on reducible supports due to a strong metal-support interaction (SMSI) has already been extensively studied. However, there is still an ongoing debate on important aspects such as the influence of oxygen or hydrogen treatments on the encapsulating overlayer. We have utilized synchrotron-based NAP-XPS in order to investigate the SMSI for Pt-loaded TiO2(110) single crystals under the influence of H2 and O2 at different pressures. In an O2 atmosphere two different, pressure-dependent phenomena, namely, an oxidation of Pt particles and a loss of Pt signal intensity, are observed at 800 K. While the oxidation is partially reversed in vacuum, the intensity of the platinum signal cannot be recovered. H2 annealing has no significant additional effect compared to vacuum annealing. In the presentation, we discuss possible origins of these observations.