The physicochemical and catalytic properties of the Pt-CeOx system

The properties of the Pt-CeO _x system prepared by the oxidation of the Pt₂Ce intermetallic compound were studied. The sample was characterized by X-ray diffraction in situ, thermogravimetry, scanning electron microscopy (with an accessory for energy dispersion analysis), transmission electron microscopy, and temperature-programmed reduction with hydrogen. The catalytic properties of the sample were studied in the model reaction of toluene hydrogenation. The oxidation of the intermetallic compound caused the appearance of metallic platinum and cerium oxide phases and high-dispersity platinum particles encapsulated in cerium oxide. Metallic platinum on the surface of the catalyst experienced rapid deactivation in the presence of hydrogen sulfide; high-dispersity platinum particles encapsulated in cerium oxide exhibited enhanced stability toward sulfur compounds.