Preparation and Properties of Stable Nanocrystalline Anatase TiO2 Colloids

✍ Scribed by X.-Q. Chen; W.-H. Shen

• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: English
• Weight: 389 KB
• Volume: 31
• Category: Article
• ISSN: 0930-7516
• DOI: 10.1002/ceat.200700450

✦ Synopsis

The nanocrystalline anatase TiO 2 colloid has widely been applied in solar energy conversion, photo-degradation of organic pollutions, photochemical disinfection, processing of sensors, and papermaking. It can be obtained from the hydrolysis of titanyl organic compounds [TiO(OOCCH 3 ) 2 and Ti 2 O(OC 4 H 9 ) 2 (OOCCH 3 ) 4 ] at low temperature and normal pressure. TEM (Transmission Electron Microscope), SEM (Scattering Electron Microscope), and LS (Layer Scattering) analysis showed that the colloidal particles are spherical and possess a narrow size distribution, that the mean size (80 C, 2 h, sample B) is 8.9 nm and its isoelectric point is 6.67. The S BET of the gel powders are 262.7457 m 2 /g (60 C, 2 h, sample A) and 258.0024 m 2 /g (80 C, 2 h, sample B). Research experiments showed that the turbidities of colloidal solutions decreased along with the decrease of water content in the mixed water-alcohol dispersants, which predicated that the colloidal stability fell when lowering the electrical conductivity of the dispersant. The zeta potentials of the colloids are 14 mV ~30 mV at pH 4.5 ~6.0 in the presence of 0.5 • 10 -2 mol L -1 NaNO 3 electrolyte. Furthermore, the UV absorbance of the nanocrystalline TiO 2 colloidal solutions increased with a decrease in particle size. The experimental results of photocatalytic degradation of the dye rhodamine revealed that the nanocrystalline TiO 2 colloidal particles from this preparation method have good photocatalytic activity, which is better if doped with 0.2 % Fe 3+ .