DISPERSION AND THERMAL-STABILITY OF VANADIUM-OXIDE CATALYSTS SUPPORTED ON TITANIA-ALUMINA BINARY OXIDE

Titania-alumina binary oxide supported vanadia catalysts calcined at d ifferent temperatures were studied by X-ray diffraction, infrared, oxy gen chemisorption and surface area measurements to establish the effec ts of vanadia loading and thermal treatments on the structure of the d ispersed vanadium oxide species. The results suggest that vanadia when calcined at 773 K is in highly dispersed state on the support surface . This dispersion is mostly retained upto a calcination temperature of 873 K. However, thermal treatments above 873 K transform vanadia and titania into crystalline phases and then TiO2 anatase into rutile.