A visible-light-active mesoporous Cr-doped TiO2 photocatalyst with worm-like channels was synthesized using an evaporation-induced self-assembly approach and characterized by X-ray powder diffraction, nitrogen adsorption-desorption, X-ray photoelectron spectroscopy, transmission electron microscope, and UV-vis diffuse reflectance, respectively. The effect of Cr3+ doping concentration on the photocatalytic activity of mesoporous TiO2 was investigated from 0.1 to 1 mol%. The characterizations indicated that the photocatalysts possessed a homogeneous pore diameter of about 8 nm with high surface area of 117 m(2)/g and a crystalline anatase pore wall doped by Cr3+. Compared with pure mesoporous TiO2, the Cr-doped TiO2 extended the photoabsorption edge into the visible light region. The results of gaseous acetaldehyde photodecomposition showed that mesoporous Cr-doped TiO2 exhibited higher photocatalytic activities than pure mesoporous TiO2 and nonporous Cr-doped TiO2 under visible light irradiation. (C) 2008 Elsevier B.V. All rights reserved.