Synthesis of nanosized TiO2/SiO2 particles in the microemulsion and their photocatalytic activity on the decomposition of p-nitrophenol

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. These particles were characterized by TEM, XRD, FT-IR, BET, TGA and DTA. From thermal analysis and XRD analysis, the anatase structure of pure titania appeared in the 300-600degreesC calcination temperature range and the rutile structure was showed above 700degreesC. However, no rutile phase was observed for the TiO2/SiO2 particles up to 800degreesC. The crystallite size decreased and the surface area of TiO2/SiO2 particles monotonically increased with an increase of the silica content. From FT-IR analysis, the band for Ti-O-Si vibration was observed and the band intensity for Si-O-Si vibration increased with an increase of the silica content. The micrographs of TEM showed that the TiO2/SiO2 nanoparticles had a spherical and a narrow size distribution. In addition, TiO2/SiO2 particles showed higher photocatalytic activity than pure TiO2 and the TiO2/SiO2 (90/10) particles showed the highest activity on the photocatalytic decomposition of p-nitrophenol. (C) 2003 Elsevier B.V. All rights reserved.