Regensburg 2025 – scientific programme

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O: Fachverband Oberflächenphysik

O 63: Oxides and Insulator Surfaces: Adsorption and Reaction of Small Molecules II

O 63.1: Talk

Wednesday, March 19, 2025, 10:30–10:45, H25

Unravelling the Photocatalysis of Alcohol on Rutile(110) — •Philip Petzoldt, Lucia Mengel, Anna Lemperle, Moritz Eder, Martin Tschurl, and Ueli Heiz — Chair of Physical Chemistry, School of Natural Sciences & Catalysis Research Center, Technische Universität München, Lichtenbergstr. 4, 85748 Garching, Germany

Heterogeneous photocatalysis is a promising tool for the environmentally benign production of chemical fuels such as hydrogen. However, the structural complexity of state-of-the-art materials makes mechanistic investigations and, in consequence, the targeted design of new catalysts extremely challenging. We employ surface science methods to explore fundamental mechanisms in photocatalysis. In this contribution, we focus on the photocatalytic hydrogen evolution from alcohols over rutile(110) loaded with Pt cluster co-catalysts. Our experimental evidence reveals a new reaction mechanism, which substantially differs from the generally assumed model of independent redox reactions. By changing active sites for both the alcohol oxidation and the hydrogen evolution reaction, we further show that the overall photoactivity strongly depends on the equilibrium of a reaction network of several elementary photo- and thermal reaction steps. Our results provide new mechanistic insights into the photocatalytic hydrogen evolution from Pt loaded titania and illustrate the importance of a comprehensive understanding of the photocatalysts (surface) chemistry.

Keywords: photocatalysis; titania; platinum clusters; UHV; mechanism