Photocatalytic decomposition of p-nitrophenol over nanosized TiO2/SiO2 particles prepared using the microemulsion method

Nanosized pure TiO2 particles were prepared by hydrolysis of TTIP in the sodium bis (2-ethylhexyl) sulfosuccinate (AOT) reverse micelles. TiO2/SiO2 nanoparticles were also prepared from TEOS as a silicon source and TTIP as a titanium source for comparison. Properties of these particles were characterized by TEM, XRD, FT-IR, BET, TGA and DTA. From XRD data, no significant rutile phase was observed even though the TiO2/SiO2 particles were calcined at 800degreesC. The presence of amorphous silica in TiO2/SiO2 particle enhanced the thermal stability of TiO2 particle and resulted in the suppression of the phase transition from anatase to rutile. The crystallite size of prepared particles decreased and the surface area increased monotonically with an increase of the silica content. From FT-IR analysis, the band for Ti-O-Si vibration was observed and the band for Si-O-Si vibration increased with an increase of the silica content. The micrographs of TEM show that the TiO2/SiO2 nanoparticles have a spherical morphology with a narrow size distribution. In addition, TiO2/SiO2 particles have higher photocatalytic activity than pure TiO2 and the TiO2/SiO2 (90/10) particles show the highest activity on the photocatalytic decomposition of p-nitrophenol.