Surface chemistry of Fe2O3-Cr2O3 and Fe2O3 catalysts

Authors:

• F. Domka,
• Anna Basińska,
• W. Przystajko,
• Ryszard Michał Fiedorow

Abstract

The acid-base and redox properties of Fe₂O₃ and Fe₂O₃-Cr₂O₃ surfaces were studied and the effect on these properties of the various iron oxide-hydroxide modifications that are used as the starting materials is described. It was found that the presence of Cr₂O₃ in Fe₂O₃-Cr₂O₃ systems increases acidity, basicity and oxidizing ability compared with Fe₂O₃ subjected to an analogous thermal treatment. Both Brönsted and Lewis acid centres were detected on the surfaces investigated, the Brönsted acid centres being sufficiently strong to convert pyridine into pyridinium ions. The preparation of Fe₂O₃-Cr₂O₃ catalysts from γ-FeOOH is recommended for obtaining surfaces distinguished by high concentrations of acid and oxidizing sites and by good catalytic activity for the water gas shift reaction. © 1984.