Trititanate nanotubes were prepared using hydrothermal method and then co-doped with Gd3+ and N through ion-exchanging with H+. They were characterized by X-ray photoelectron spectra (XPS), high-resolution transmission electronmicroscopy (HRTEM), X-ray diffraction (XRD), UV-vis diffusion reflection spectra (UV-vis DRS) and photoluminescence (PL) spectra. The photocatalytic activities were investigated with Rhodamine B as the model pollutant. The results indicated that synergistic reaction occurred when codoping with Gd3+ and N and the photocatalytic activities of TiO2 were enhanced significantly under visible light irradiation. (C) 2010 Elsevier B.V. All rights reserved.