Most of tantalate photocatalysts are mainly synthesized by solid-state (SS) reaction methods and only show photocatalytic activity under UV light irradiation. Ta2O5 as a raw material shows an extremely high chemical stability, limiting its application to a few systems. A novel nanometer Bi3TaO7 photocatalyst was synthesized by a facile and low-cost sol-gel method using Ta2O5 and Bi(NO3)(3)center dot 5H(2)O as the Ta and Bi sources, respectively. The as-obtained samples were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM). UV-vis diffuse reflection spectroscopy (DRS) and Fourier transform infrared spectroscopy (FT-IR). The band gap energy of the as-obtained nanometer Bi3TaO7 photocatalyst was determined to be about 2.75-2.86 eV. The Bi3TaO7 nanopowders show a strong adsorbability and a high visible-light photocatalytic activity for the degradation of 4BS, which can be ascribed to the surface physicochemical properties and structure of the Bi3TaO7 nanometer catalyst. The degradation of 4BS is attributed to the photocatalysis but not to the adsorption of 4BS on the as-prepared catalyst. (C) 2010 Elsevier Inc. All rights reserved.