Effects of calcination temperature on morphology and structure of CeO2 nanofibers and their photocatalytic activity

Calcination temperature plays a critical role on morphology and structure of CeO2 nanofibers, thus affecting its photocatalytic activity. CeO2 nanofibers with diameter of 95 nm were successfully fabricated by electrospinning combining with calcination. The calcination temperature was determined by TGA results ranging from 500 °C to 800 °C. The morphology and structure of samples obtained with different calcination temperatures, have been characterized by SEM and XRD. Meanwhile, the specific surface area of samples were checked by BET, that was decreased 17 times from 56.3 m2/g to 3.3 m2/g, as the temperature increasing from 500 °C to 800 °C. Normally, the higher specific surface area, the more efficiency photocatalytic activity. But it was interesting that the photodegradation rate of methylene blue was increased from 67% to 98% for CeO2 catalyst obtained at 500 °C and 800 °C, with 4 times higher kinetic constant reaction rate under UV irradiation for 60 min. It demonstrates that the photocatalytic activity of CeO2 nanofibers catalyst is not directly related to the specific surface area, and increasing the calcination temperature has a positive effect for the photocatalytic efficiency.