摘要
The vanadium (V)-doped mesoporous titanium dioxide (TiO 2 ) nanoparticles at low V/Ti ratios ranging from 0 to 2 wt% were prepared using hydrolytic sol-gel method in the presence of tri-block copolymer Pluronic F127. The microstructures of TiO 2 in terms of morphology, crystallization, chemical states of species, surface area, and band gap were characterized by SEM, TEM, XRPD, XPS, surface area analyzer, and UV-Vis spectrophotometer, respectively. SEM images showed that the V-doped TiO 2 nanoparticles were porous structures, and the surface areas and pore sizes ranged from 86 ± 9 to 96 ± 15 m 2 /g and from 12 ± 4 to 15 ± 2 nm, respectively. The XRPD patterns indicated that V-doped mesoporous TiO 2 after calcination at 500 °C was mainly anatase phase, and the crystallite sizes were in the range 14-16 nm, which are consistent with the results obtained from SEM images. XPS spectra and HRTEM images showed that vanadia was doped both on the surface and in the lattice of anatase TiO 2 . A slight red-shift in wavelength absorption was observed when V/Ti ratio increased from 0 to 2 wt%. Methylene blue (MB) was further used as the target compound to examine the photocatalytic activity of V-doped mesoporous TiO 2 nanocatalysts under illumination of solar simulator or UV light. Addition of vanadium ions slightly decreased the photocatalytic activity of TiO 2 toward the decolorization of MB under the illumination of UV light at 305 nm. However, a 1.6-1.8 times increase in rate constants for MB photodegradation was observed when 0.5-1.0 wt% V-doped TiO 2 was illuminated with sunlight at AM 1.5. © 2009 Elsevier B.V. All rights reserved.