V-doped TiO2 (V-TiO2) nanoparticles were prepared by a simple one-step flame spray pyrolysis (FSP) technique. The obtained samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), electron paramagnetic resonance (EPR) spectra, UV-vis absorption spectroscopy, and nitrogen adsorption-desorption methods. Benefiting from the short residence time and high quenching rate during the flame spray process, V4+ ions are successfully incorporated into the crystal lattice of TiO2. It reveals that V doping favors the primary particle size growth as well as the increase of rutile content in the products. The photocatalytic activity of the V-TiO2 samples under UV and visible light irradiation were evaluate by the photocatalytic degradation of methylene blue (MB) and 2,4-dichlorophenol (2,4-DCP), respectively. It was found that V doping enhances the photocalytic activity under both UV and visible light irradiation. Especially, under visible light irradiation, the degradation rate of 2,4-dichlorophenol over 1%V-TiO2 is two times higher than that over undoped TiO2. The photocatalytic mechanisms for V-TiO2 samples under UV and visible light irradiation were tentatively discussed. (C) 2009 Elsevier B.V. All rights reserved.