PLATINUM STATE IN HIGHLY ACTIVE Pt/CeO2 CATALYSTS FROM THE X-RAY PHOTOELECTRON SPECTROSCOPY DATA
A.I. Stadnichenko1,2, V.V. Muraviev1,2, V.A. Svetlichnyi3, A.I. Boronin1,2
1Boreskov Institute of Catalysis, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
2Novosibirsk National Research State University, Novosibirsk, Russia
3Tomsk State University, Tomsk, Russia
Keywords: платина, оксид церия, твердые растворы, РФЭС, platinum, ceria, solid solutions, XPS
Abstract
The states of components of highly efficient Pt/CeO2 catalysts for low-temperature oxidation of carbon monoxide are studied in detail by X-ray photoelectron spectroscopy (XPS). Using the precise calibration of the spectra relative to the internal standard and the fitting of Ce3d and Pt4f spectra by elementary doublets, we found the features of the platinum interaction with the ceria lattice. It is shown that when the co-deposition technique is used, depending on the quality of stock solutions, it is possible to obtain both homogeneous solid solutions of platinum in the ceria lattice and solutions containing polyatomic platinum associates of the (PtO)m type. It is found that when homogeneous PtCeOx solid solutions are stored in air at room temperature, the homogeneous solutions slowly pass into the state of solutions with platinum associates. Mechanical mixtures of metallic platinum and ceria nanoparticles, synthesized by laser ablation, were also investigated in the course of their annealing in the air. The results obtained from the Pt4f spectra completely confirm the specific features of the interaction of platinum with ceria.
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