The effect of thermal treatment in TiO2 photocatalytic activity

Thermal analysis (TA) techniques were applied in order to predict the influence of thermal treatment, on the photocatalytic performance of TiO2 materials prepared via sol-gel method in various temperatures between 250 and 600 A degrees C in different alcohols (methanol/ethanol). Calorimetric results showed that the formation of TiO2 is faster in methanol than in ethanol. TA patterns showed that slight differences observed in the thermal behavior of the material can affect both its textural and photocatalytic properties. The appearance of the endothermic peaks in the area of 250-450 A degrees C refer to crystallization of amorphous to crystalline phases or to the transformation of the less active rutile to the more active anatase phase. The results obtained from TG/DSC are in accordance to XRD results and SEM images. Thermal treatment affects the photocatalytic properties of the materials. Samples prepared in methanol showed better photocatalytic behavior than those in ethanol while the increase in temperature decreases the effectiveness of the materials.