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 39.6: Vortrag

Dienstag, 18. März 2025, 15:15–15:30, H4

Adsorption and activation of CO₂ on CeO₂ surfaces — •Zairan Yu, Shuang Chen, Wangtao Li, Alexei Nefedov, Christof Wöll, and Yuemin Wang — Institute of Functional Interfaces (IFG), Karlsruhe Institute of Technology (KIT), 76344 Eggenstein-Leopoldshafen, Germany

CO₂ activation and its subsequent transformation into valuable chemicals pose significant challenges in heterogeneous catalysis. Most studies have focused on powdered catalysts with various facets and unknown defect densities, whereas much less is known about the surface chemistry of CO₂ on well-defined oxide surfaces. Here, we investigate CO₂ adsorption and activation on fully oxidized CeO₂(111) single-crystal surfaces using polarization-resolved IR reflection absorption spectroscopy (IRRAS). The comprehensive IRRAS data reveal that CO₂ is weakly bound to CeO₂(111) at 117 K in a linear, physisorbed state. At elevated temperatures (300 K) and pressures, CO₂ undergoes activation forming an unusual horizontal carbonate. Additionally, in the presence of surface hydroxyl groups, formate and HCO₃ species are identified. These experimental findings are supported by complementary theoretical analysis. Furthermore, the IRRAS results are in excellent agreement with the in situ transmission IR data obtained for CO adsorption on octahedral ceria nanoparticles, which predominantly expose (111) facets. This work was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) -Project-ID 426888090- SFB 1441.

Keywords: Ceria; CO2 activation; IRRAS; Surface chemistry; DFT