Advanced oxidation technologies are a friendly environmental approach for the remediation of industrial wastewaters.Here,one pot synthesis of mesoporous WO3 and WO3-graphene oxide (GO) nanocomposites has been performed through the sol-gel method.Then,platinum (Pt) nanoparticles were deposited onto the WO3 and WO3-GO nanocomposite through photochemical reduction to produce mesoporous Pt/WO3 and Pt/WO3-GO nanocomposites.X-ray diffraction (XRD) findings exhibit a formation of monoclinic and triclinic WO3 phases.Transmission Electron Microscope (TEM) images of Pt/WO3-GO nanocomposites exhibited that WO3 nanoparticles are obviously agglomerated and the particle sizes of Pt and WO3 are ～10 nm and 20-50 nm,respectively.The mesoporous Pt/WO3 and Pt/WO3-GO nanocomposites were assessed for photocatalytic degradation of Methylene Blue (MB) as a probe molecule under visible light illumination.The findings showed that mesoporous Pt/WO3,WO3-GO and Pt/WO3-GO nanocomposites exhibited much higher photocatalytic efficiencies than the pure WO3.The photodegradation rates by mesoporous Pt/WO3-GO nanocomposites are 3,2 and 1.15 times greater than those by mesoporous WO3,WO3-GO,and Pt/WO3,respectively.The key factors of the enhanced photocatalytic performance of Pt/WO3-GO nanocomposites could be explained by the highly freedom electron transfer through the synergetic effect between WO3 and GO sheets,in addition to the Pt nanoparticles that act as active sites for O2 reduction,which suppresses the electron hole pair recombination in the Pt/WO3-GO nanocomposites.