Three-Dimensional Dendritic C/PbWO4 Catalysts: Preparation and Photocatalytic Performance in Degrading Different Dyes

Three-dimensional dendritic C/PbWO4 composite photocatalyst with different C content (Mass fraction=0.13%, 0.26%, 0.52%, 0.78%) was synthesized by a hydrothermal method. The photocatalysts were characterized by X-ray diffraction, N-2 sorption measurements, scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, ultraviolet-visible diffuse reflectance spectroscopies, photoluminescence, and photoelectrochemical measurement. The results showed that the dendritic C/PbWO4 composite photocatalyst with 0.52% C exhibits the best photocatalytic performance in degrading orange II, methyl orange and rhodamine B. Under the light irradiation for 100 min, the degradation rate of the acid orange II (20 mg.L-1) over 0.52% C/PbWO4 reached 97% which was about 2.48 times as that of bare PbWO4. The main reason for the increase of activity is that carbon attached to the surface of the catalyst becomes the electron trapping center, and it can effectively capture the photogenerated electrons. Therefore, the photo-generated electron-hole pairs were effectively separated to produce more active species (center dot OH, h(+)) to participate in the degradation of organic dye molecules.