Regensburg 2025 – scientific programme

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O: Fachverband Oberflächenphysik

O 39: Oxides and Insulator Surfaces: Adsorption and Reaction of Small Molecules I

O 39.3: Talk

Tuesday, March 18, 2025, 14:30–14:45, H4

Towards Understanding the Photoreactivity of SrTiO₃ through Studies in Ultra-High Vacuum — •Anna Lemperle, Philip Petzoldt, 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 offers the prospect of utilising solar energy for the zero-carbon production of hydrogen from water. The most prominent photocatalytic materials currently employ SrTiO₃ as the light harvesting semiconductor. While these catalysts have been shown to promote a stoichiometric reaction, their photocatalytic performance is still insufficient for economically viable application. As their structural complexity impedes mechanistic studies, model systems are necessary to elucidate individual reaction steps and connect catalytic results to distinct catalyst properties. This approach aims to attain a molecular understanding of the reaction mechanisms involved in water splitting in order to enable a more targeted design of photocatalysts. In this contribution, we discuss first results on the reactivity of water and oxygen on the bare SrTiO₃(110) surface. Results obtained by combining temperature programmed desorption and studies under illumination highlight the importance of bulk and surface oxygen for the reactivity of SrTiO₃.

Keywords: photoreactions; SrTiO3; water adsorption; hydrogen evolution; oxygen vacancies