Wang, J. / Sauter, E. / Nefedov, A. / Heißler, S. / Maurer, F. / Casapu,  M. / Grunwaldt, J. D. / Wang, Y / Wöll, C. (2022)

J. Phys. Chem. C, 2022, doi.org/10.1021/acs.jpcc.2c02420

Abstract

CeO2-supported Pt nanoparticles are of prominent technological interest due to their excellent dispersion and thus performance in a wide range of catalytic reactions. In this study, the dynamic structural evolution of Pt supported on ceria particles in response to changes of reaction conditions has been studied by surface-ligand infrared spectroscopy in conjunction with X-ray photoelectron spectroscopy. The combined results obtained under oxidative and reductive conditions reveal that oxidation at elevated temperatures leads to a pronounced fragmentation of the Pt nanoparticles, yielding positively charged Pt single atoms bound to the surface of the ceria particles. Subsequent reduction carried out at different temperatures leads to the formation of various metallic Pt species including small clusters and nanoparticles, dependent on the dispersion of Pt during the oxidation step and the kind of reduction. The present spectroscopic data provide a thorough insight into the structural and electronic properties of CeO2-supported Pt particles that show strong changes of charge state and size depending on the reaction conditions.

Download