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O: Fachverband Oberflächenphysik

O 21: Poster Heterogeneous Catalysis

O 21.6: Poster

Montag, 17. März 2025, 18:00–20:00, P2

Tuning the ceria island orientation: from (111) to (100)-oriented islands — •Maja Atlas, Raquel Sanchez-Barquilla, and Jan Ingo Flege — Applied Physics and Semiconductor Spectroscopy, Brandenburg University of Technology Cottbus-Senftenberg, Germany

Inverse catalysis systems, where the reducible oxide is anchored on the metallic support, have shown a better performance compared with its traditional counterparts due to the strong metal support interaction. Among catalytic materials, ceria (CeO₂) is used in a wide range of applications, due to its oxygen storage and redox properties. In particular, the catalytic activity of Cu(111) can be substantially enhanced when depositing CeO_x on top, achieving direct methanol production from CO₂. In situ near ambient pressure X-ray photoemission spectroscopy (NAP-XPS) measurements have shown that the activated CO₂ molecule is stabilized by Ce³⁺ sites during the reaction. Moreover, epitaxially grown CeO₂ islands can have two different orientations on Cu(111): the (111)-oriented islands appear first and with lower oxygen pressure, while the (100)-oriented phase can be enhanced by increasing the oxygen exposure. Here, we present a structural and chemical study of the ceria islands growth as a function of temperature, oxygen pressure and deposition rate. By varying these parameters, we can study the relation between the phase and the Ce³⁺/Ce⁴⁺ ratio, using XPS, low energy electron diffraction (LEED) and scanning tunneling microscopy (STM).

Keywords: Ceria; LEED; XPS; STM