(BiO)(2)CO3/BiOI heterojunctions were prepared in-situ by a pore impregnating method using HI aqueous solution. The specific surface area, structure, morphology, and charge separation properties of the heterostructures prepared were characterized by Brunauer-Emmett-Teller (BET) method, X-ray diffraction (XRD), scanning electron microscopy (SEM), and surface photovoltage (SPV) spectroscopy, respectively. The active species were investigated using scavengers. The photocatalytic activities of (BiO)(2)CO3/BiOI heterojunctions towards discoloration of rhodamine B (RhB) under simulated sun light irradiation were evaluated. Benefiting from enhanced charge separation efficiency, the composite photocatalysts exhibit higher photocatalytic performance than the pure BiOI. Finally, the possible reason was discussed. (C) 2015 Elsevier B.V. All rights reserved.