Heterostructured Fe3O4/Bi2O2CO3 photocatalyst was synthesized by a two-step method. First, Fe3O4 nanoparticles with the size of ca. 10 nm were synthesized by chemical method at room temperature and then heterostructured Fe3O4/Bi2O2CO3 photocatalyst was synthesized by hydrothermal method at 180 degrees C for 24 h with the addition of 10 wt% Fe3O4 nanoparticles into the precursor suspension of Bi2O2CO3. The pH value of synthesis suspension was adjusted to 4 and 6 with the addition of 2 M NaOH aqueous solution. By controlling the pH of synthesis suspension at 4 and 6, sphere- and flower-like Fe3O4/Bi2O2CO3 photocatalysts were obtained, respectively. Both photocatalysts demonstrate superparamagnetic behavior at room temperature. The UV-vis diffuse reflectance spectra of the photocatalysts confirm that all the heterostructured photocatalysts are responsive to visible light. The photocatalytic activity of the heterostructured photocatalysts was evaluated for the degradation of methylene blue (MB) and methyl orange (MO) in aqueous solution over the photocatalysts under visible light irradiation. The heterostructured photocatalysts prepared in this study exhibit highly efficient visible-light-driven photocatalytic activity for the degradation of MB and MO, and they can be easily recovered by applying an external magnetic field. (C) 2013 Elsevier B.V. All rights reserved.