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O: Fachverband Oberflächenphysik
O 73: Poster Metal and Semiconductor Substrates: Adsorption and Reactions of Small Molecules
O 73.3: Poster
Mittwoch, 19. März 2025, 18:00–20:00, P2
Poisoning resistance of GaPt SCALMS model systems — •Christoph Wichmann1,2, Michael Moritz2, Haiko Wittkämper2, Tzung-En Hsieh3, Johannes Frisch3, Macus Bär2,3,4, Hans-Peter Steinrück2, and Christian Papp1 — 1FU Berlin, Germany — 2FAU Erlangen, Germany — 3Helmholtz-Zentrum Berlin, Germany — 4Helmholtz Institute Erlangen-Nürnberg Germany
Supported catalytically active liquid metal solutions (SCALMS) are a novel concept, where low amounts of a catalytically active transition metal is dissolved in another low melting metal, which acts as a matrix. The highly dynamic surface provides an interesting system offering high activity and remarkable stabilities for dehydrogenation reactions. For industrial applications, different challenges have to be met. One of them is the presence of catalytic poisons in the catalytic feed such as sulfur compounds. Therefore, a model system of a macroscopic GaPt droplet with a low Pt content (1 at.%) and nanoscopic GaPt particles were investigated during the exposure to thiophene as catalyst poison using X-ray photoelectron spectroscopy (XPS) under ultra-high vacuum and near-ambient pressure (0.1-0.2 mbar) conditions. The formation of Ga-sulfides at the surface of the catalyst is observed, leading to an accumulation of Pt in / under this layer. For higher temperatures (>650 K), the dissolution of the formed Ga-sulfides into the liquid metallic Ga-matrix is observed. In all cases, no Pt-sulfide was formed, indicating a resistance of the active Pt sites towards sulfur poisoning of SCALMS.
Keywords: liquid metals; thiophene; gallium; platinum; sulfur