Effect of calcination temperatures on physicochemical properties of vanadium–antimony mixed oxide catalysts

A vanadium–antimony mixed oxide catalyst has been prepared via slurry method. The precursors obtained were calcined in different calcination temperatures, i.e. 673, 773 and 873 K and compared its effect on the physicochemical properties of the oxide. These catalysts were characterised by X-ray diffraction (XRD), FTIR spectroscopy, BET surface area measurements and scanning electron microscopy (SEM). Calcination at high temperature was found to promote the formation of ≈VSbO4 and α-Sb2O4 phase, while the formation of Sb6O13 phase was inhibited. The nature of the oxidizing species in the VSbO catalysts were studied by temperature programmed desorption (TPD) of oxygen and temperature programmed reduction (TPR) of hydrogen. Results revealed that two types of kinetically different oxygen states exist in the catalysts and calcination at high temperature, i.e. 873 K produced a more reducible sample.