Аннотация:Pd-, Fe-, and Pd–Fe-containing systems on SiO2 are prepared by the metal vapor technique. The Pd–Fe/SiO2 nanocomposite is found to exhibit a significantly higher activity in the CO oxidation than its monometallic analogs. The composition of thePd–Fe/SiO2 system and its evolution during catalysis are characterized by X-ray photoelectron spectroscopy; the initial Pd–O–Fe phase is shown to transform into the Pd–PdFeOx phase, which stimulates a synergistic effect.