Regensburg 2025 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

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

O 39.5: Vortrag

Dienstag, 18. März 2025, 15:00–15:15, H4

Complex structural arrangements at the CO₂/In₂O₃(111) interface — Sarah Tobisch¹, Andreas Ziegler², Marco Knapp¹, Michael Schmid¹, Ulrike Diebold¹, Bernd Meyer², and •Margareta Wagner¹ — ¹Institut für Angewandte Physik, TU Wien — ²ICMM & CCC, FAU-Erlangen-Nürnberg

Promising catalysts for the hydrogenation of CO₂ to methanol are highly desired to address the pressing issue of rising carbon emissions. Since reactions take place at the interface, understanding the fundamental properties and behavior of molecular species on well-defined surfaces is crucial for designing model catalysts.

In₂O₃ has gained attention as catalytic material due to its high selectivity for methanol synthesis via CO₂ reduction. In this work, the adsorption and interaction of CO₂ molecules on In₂O₃(111) were investigated in detail at the atomic scale and under UHV conditions. We employ non-contact atomic force microscopy (AFM) and compared our findings with results from temperature programmed desorption (TPD) and x-ray photoelectron spectroscopy (XPS) measurements, as well as density functional theory (DFT) calculations. AFM images of the In₂O₃(111) surface show 10 molecular features per surface unit cell arranged in a systematic and uniform order, albeit breaking the threefold symmetry of the substrate surface. The adsorption sites of all individual molecules were identified; some of them are carbonate species, in agreement to XPS showing a mixture of CO₂ molecules and CO₃²⁻. Moreover, the desorption and structural evolution with increasing temperature was studied.

Keywords: CO2 reduction; TPD; AFM; indium oxide