Berlin 2018 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 9: Focus Session: Frontiers in Reducible Oxide Surface Science I

O 9.7: Vortrag

Montag, 12. März 2018, 12:45–13:00, HFT-FT 131

Spectroscopic evidence for the controlled formation of catalytically active Pt nanoparticles supported on ceria — •Junjun Wang, Alexei Nefedov, Christof Wöll, and Yuemin Wang — Institute of Functional Interfaces, Karlsruhe Institute of Technology, 76344, Eggenstein-Leopoldshafen, Germany

Ceria-supported Pt catalysts have received increased attention from both fundamental and technological perspectives due to their applications in several fields such as automotive exhaust cleaning and hydrocarbon reforming. It has been proposed that the catalytic activity and utilization efficiency of Pt can be significantly enhanced by decreasing the particle size to ultrafine clusters. In the present work, the surface structure and oxidation states of ceria-supported Pt nanoparticles under alternating reductive and oxidative conditions were monitored by ultrahigh vacuum IR spectroscopy using CO as a probe molecule. Our results provided direct spectroscopic evidence for the re-dispersion of Pt particles in ceria after oxidation at moderate temperatures. It was found that the subsequent reduction treatments at different temperatures lead to a controlled formation of ultrafine Pt particles. The combined IR and high-resolution XPS data allowed us to gain detailed insights into the strong Pt-ceria interaction and the dynamic behavior of Pt clusters under reductive and oxidative atmospheres.