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Zusammenfassung:
Platinum nanoparticles dispersed on nanosized ceria are active for CO oxidation at room temperature after hydrogen pretreatment. High angular annular dark field scanning transmission electron microscopy (HAADF-STEM) analysis of the reduced catalyst shows spreading of the 1 nm sized platinum particles under the electron beam, characteristic for a two-dimensional strong metal–support interaction. In situ X-ray absorption fluorescence spectroscopy (XAFS) reveals a Pt–O distance of 2.1 Å, which is significantly longer than the Pt–O distance in PtO2 (2.0 Å). This elongated Pt–O distance can be related to interaction of the platinum species with cerium oxide in the form of a low-temperature active species–support interaction. These findings contribute to the general understanding of catalytic systems operating at low temperature.
