Microstructure characteristics and photoreactivity of calcined P-25 TiO2

The microstructural characteristics of P-25 TiO2, photocatalysts calcined at 600, 650, 700, 750, 800, 900 and 1000 degrees C have been studied using XRD, TEM and BET. The photocatalytic activity of the samples were also examined using the degradation of phenol as a model reaction. The results indicate that the calcination significantly affects both microstructural characteristics and photoactivity, and there is an apparent relationship between photocatalytic activity and certain microstructural characteristics. Over the range of calcination temperatures and durations studied, the sample calcined at 650 degrees C for 3 h revealed the highest photoreactivity, which can be ascribed to an improvement in crystallinity on calcination. The increase in the rutile content and grain size caused by the calcination at higher temperatures were observed to decrease the photocatalytic activities of the TiO2 samples.