Preparation, characterization and photocatalytic performance of g-C3N4/Bi2WO6 composites for methyl orange degradation

The g-C3N4/Bi2WO6 composites have been synthesized and used as photocatalysts for degradation of methyl orange (MO) dye. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), infrared spectroscopy (IR), UV–visible diffuse reflection spectroscopy (DRS), and N2 physisorption isotherms were used to characterize the physicochemical properties of the materials. With the increase of hydrothermal time, the morphology of Bi2WO6 evolved from nanoparticles to microplates, flower-like and helix/tyre-like superstructures; in the meanwhile the g-C3N4 component was gradually dissolved. Such obtained g-C3N4/Bi2WO6 composites showed optical band gap in the range of 2.67–2.75 eV. Photocatalytic results showed that g-C3N4/Bi2WO6 composites are more active than either pure Bi2WO6 or g-C3N4, and the weight ratio of g-C3N4 to Bi2WO6 and the hydrothermal time significantly affected the degradation efficiency of the materials. The optimum weight ratio of g-C3N4 to Bi2WO6 was 0.5:1, and that for hydrothermal time was 6 h at 160 °C.