Preparation, characterization and photocatalytic performance of g-C_3N_4/Bi_2WO_6 composites for methyl orange degradation

摘要

The g-C_3N_4/Bi_2WO_6 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 N_2 physisorption isotherms were used to characterize the physicochemical properties of the materials. With the increase of hydrothermal time, the morphology of Bi_2WO_6 evolved from nanoparticles to microplates, flower-like and helix/tyre-like superstructures: in the meanwhile the g-C_3N_4 component was gradually dissolved. Such obtained g-C_3N_4/Bi_2WO_6 composites showed optical band gap in the range of 2.67-2.75 eV. Photocatalytic results showed that g-C_3N_4/Bi_2WO_6 composites are more active than either pure Bi2WOG or g-C_3N_4, and the weight ratio of g-C_3N_4 to Bi_2WO_6 and the hydrothermal time significantly affected the degradation efficiency of the materials. The optimum weight ratio of g-C_3N_4 to Bi_2WO_6 was 0.5:1, and that for hydrothermal time was 6 h at 160 °C.