A novel hydrothermal approach is developed for the first time to synthesize hierarchical BiVO4/Bi2O2CO3 nanocomposites with reactive crystalline facets using urea as a morphology mediator. The as-prepared samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, Fourier transform infrared spectroscopy. N-2 absorption-desorption isotherms and UV-visible diffuse reflectance spectroscopy. The photocatalytic activity of the as-prepared samples was evaluated towards degradation of Rhodomine B (RhB) by visible-light. Our results indicate that both physical parameters and associated photocatalytic activity of BiVO4/Bi2O2CO3 nanocomposites can be tuned by urea concentration and reaction time in the synthesis process. With increasing urea concentration, the specific surface area, pore volume and average pore size increase. Compared to BiVO4 and Bi2O2CO3 bulk counterpart, BiVO4/Bi2O2CO3 nanocomposites show enhanced photocatalytic degradation activity of RhB. The mechanisms for the formation of BiVO4/Bi2O2CO3 nanocomposites and enhanced photoreactivity are discussed. (C) 2011 Elsevier B.V. All rights reserved.