It has been discovered that many oxides can disperse spontaneously onto the supported surfaceto form a monolayer. When the catalysts are up to the monolayer, the oxide remains on the support as amorphous phase or in other words, it is well dispersed. Above the monolayer, X-ray diffractrograms indicate the presence of crystalline oxide. The monolayer of MeOx/TiO2 catalysts (Me = Mo, Co, Ni) were determined by X-ray Diffraction (XRD). The selective oxidations of hydrocarbon on oxide catalysts are known to proceed by a redox mechanism (Mars-van Krevelen mechanism). So the redox properties of the catalysts are important. The redox properties of these catalysts were studied by TPR (Temperature- Programmed Reduction).
