Mechanism of low-temperature CO oxidation on a model Pd/Fe2O3 catalyst

A model Pd/Fe₂O₃ catalyst prepared by the vacuum technique has been studied in the carbon monoxide oxidation in the temperature range of 300–550 K at reagent pressures P(CO)=16 Torr, P(O₂)= 4 Torr. It has been shown that the activity of the fresh catalysts is determined by palladium. According to the XPS data, the reduction with carbon monoxide results in the formation of Fe²⁺ (formally Fe₃O₄) and appearance of the catalytic activity in this reaction at low temperatures (350 K). High low-temperature activity of the catalyst is supposed to be connected with the reaction between oxygen adsorbed on the reduced sites of the support (Fe²⁺) and CO adsorbed on palladium (CO_ads) at the metal–oxide interface.