Heterostructured sesame-biscuit-like Bi2O2CO3/Bi2MoO6 nanocomposites were successfully prepared via a facile anion exchange approach under hydrothermal process with the graphitic carbon nitride (g-C3N4) as the precursor of carbonate anion. The Bi2O2CO3/Bi2MoO6 nanocomposites are based on ca. 30-45 nm thick single-crystal Bi2MoO6 nanoplatelets embedded with homogeneously dispersed Bi2O2CO3 nanoparticles (less than 10 nm). The intimate interfacial contact between the Bi2O2CO3 nanoparticles and the Bi2MoO6 nanoplatelets endows the nanocomposite catalysts with high visible light photocatalytic activity for the degradation of rhodamine B. The photocatalyst prepared with 11 wt% g-C3N4 as the precursor shows the highest activity, which can degrade 99% rhodamine B in 30 min. The degradation rate of the Bi2O2CO3/Bi2MoO6 photocatalyst is more than 64 times faster than that of using bare Bi2MoO6 under visible light irradiation. The dramatically enhanced photocatalytic activity of the Bi2O2CO3/Bi2MoO6 photocatalysts can be attributed to the large heterojunction interface, intrinsically layered structure, two-dimensional morphology and effective separation of the photoinduced carriers at the interfaces and in the semiconductors. In addition, the Bi2O2CO3/Bi2MoO6 catalyst is highly stable during the reaction and can be used repeatedly. These features suggest the current heterostructured photocatalysts can be applied in environmental remediation and waste water treatment. This method may usher a new phase for the synthesis of novel and highly efficient Bi2O2CO3-based heterostructures for light-harvesting and energy conversion applications. (C) 2013 Elsevier B.V. All rights reserved.