Novel WO3/H2WO4 heterostructures with different contents of WO3 were synthesized through a simple thermodecomposition method. Thermogravimetry and differential thermal analysis (TG-DTA), X-ray powder diffraction (XRD), Fourier transform infrared spectrometry (FT-IR), UV-vis diffuse reflectance spectroscopy (DRS) and N-2 adsorption and desorption isotherms were employed to study the structures, morphologies, optical properties and specific surface area of the as-prepared samples. Degradation of rhodamine B (RhB) was carried out to evaluate the photocatalytic activity of samples under visible light irradiation (lambda > 420 nm). WO3/H2WO4 heterostructure with 51.04 wt% WO3 presented the highest photocatalytic activity with apparent k(app) of 0.0330 min(-1). The increased photocatalytic activity of WO3/H2WO4 could be attributed to the formation of the heterojunction between WO3 and H2WO4, which 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 RhB. (C) 2011 Elsevier B.V. All rights reserved.