Physical studies of MoO3 catalysts on silica and carbon supports

The nature and characteristics of the catalytic surface of supported MoO3 catalysts were studied. Changes that occurred on oxidizing alcohols in air over carbon and silica supported MoO3 were examined. Structural data were combined with electron microscopy and photoelectron spectroscopy to demonstrate that the carbon support promotes segregation and fragmentation of MoO3, whereas sintering occurs on silica. Results indicated that this may be correlated with a synergism between the carbonaceous material and metal oxide which provides a reoxidation pathway for reduced Mo, thus preventing formation of extended zones of MoO2, which is inactive for the oxidation of alcohols.