Novel p-n junction photocatalysts BiOI/(BiO)(2)CO3 with different contents of BiOI were in situ synthesized by etching (BiO)(2)CO3 precursor with hydroiodic acid (HI) solution. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectrometry (FT-IR), energy-dispersive spectroscopy (EDS) and UV-vis diffuse reflectance spectroscopy (DRS) were employed to study the structures, morphologies and optical properties of the as-prepared samples. Under visible light (lambda >420 nm), BiOI/(BiO)(2)CO3 hybrid displayed much higher photocatalytic activity than pure (BiO)(2)CO3 and BiOI for the degradation of methyl orange (MO). The increased photocatalytic activity of BiOI/(BiO)(2)CO3 could be attributed to the formation of the p-n junction between p-BiOI and n-(BiO)(2)CO3, which effectively suppresses the recombination of photoinduced electron-hole pairs. Moreover, the tests of radical scavengers confirmed that O-center dot(2)- and h(+) were the main reactive species for the degradation of MO. (C) 2012 Elsevier B.V. All rights reserved.