Preparation and visible light photocatalytic activity of Bi 2O 3/Bi 2WO 6 heterojunction photocatalysts

Abstract

The Bi 2O 3/Bi 2WO 6 heterojunction photocatalysts were prepared by a two-step solvothermal process using Bi(NO 3) 3-ethylene glycol solution as Bi source. The catalysts were characterized by X-ray diffraction, scanning and transmission electron microscopy, X-ray photoelectron spectroscopy, and UV–vis diffuse reflection spectroscopy. The heterostructure catalysts are composed of Bi 2O 3 nanoparticles as modifier and 3D Bi 2WO 6 microspheres as substrate. Bi 2O 3 nanoparticles with diameters of about 10–15 nm are tightly grown on the lateral surface of the Bi 2WO 6 microspheres. The hierarchical Bi 2O 3/Bi 2WO 6 microspheres exhibit higher photocatalytic activity than the single phase Bi 2WO 6 or Bi 2O 3 for the degradation of rhodamine B under visible light illumination ( λ>420 nm). The enhancement of the photocatalytic activity of the Bi 2O 3/Bi 2WO 6 heterojunction catalysts can be ascribed to their improved light absorption property and the reduced recombination of the photoexcited electrons and holes during the photocatalytic reaction. The effect of loading amount of Bi 2O 3 on the catalytic performance of the heterojunction catalysts was also investigated and the optimal content of Bi 2O 3 is 3 wt%. The Bi 2O 3/Bi 2WO 6 heterojunction photocatalysts are essentially stable during the photocatalytic process.