Influence of the preparation method on the behaviour of Fe-Mo catalysts for the oxidation of methanol

A series of Fe-Mo catalysts with different properties was prepared by modification of the synthesis variables. Their catalytic behaviour in the oxidation reaction of methanol to formaldehyde was determined. The differences in their textural, morphological, chemical and structural properties were determined using nitrogen adsorption, SEM-energy dispersive X-ray analysis, X-ray photoelectron spectroscopy, X-ray diffraction and Fourier transform-infrared analyses. We have attempted to establish relationships between these properties and their catalytic activity in the above reaction. We have found that their catalytic behaviour principally correlated with the atomic ratio of Mo: Fe. This ratio was sensibly higher than that required stoichiometrically for iron(III) molybdate.