Graphitic carbon nitride (g-C3N4) is an emerging metal-free catalyst, and has attracted considerate research interests in photocatalysis. For improving the low photocatalytic activity due to the polymeric nature, a variety of methods have been developed. In this study, polyoxometalate (POMs) functionalized g-C3N4 were synthesized using a facile hydrothermal method as novel photocatalysts. The photocatalysts were characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), N-2 sorption isotherms, thermogravimetric analysis (TGA), and UV-vis diffusion reflectance spectroscopy (UV-vis DRS). The photocatalytic properties were evaluated in photodecomposition of aqueous methylene blue (MB) and phenol under UV-visible light irradiations. Compared to pristine g-C3N4, POMs modified samples demonstrated enhanced efficiencies in photodegradation of MB and phenol. It was suggested that increased specific surface area, porous volume and efficient charge transfer would be responsible for the improved photocatalysis. This study proves the promising role of POMs in modification of novel photocatalysts. (C) 2015 Elsevier Inc. All rights reserved.