Novel one-dimensional Bi2O3–Bi2WO6 p–n hierarchical heterojunction with enhanced photocatalytic activity

Abstract

A novel one-dimensional (1D) Bi₂O₃ nanorod–Bi₂WO₆ nanosheet p–n junction photocatalyst was prepared by a three-step synthetic route. The obtained products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and N₂-sorption–desorption and Brunauer–Emmett–Teller (BET) surface area. Bi₂O₃ rods with the diameter of about 200 nm were obtained by calcining a Bi(OHC₂O₄)·2H₂O precursor. Bi₂WO₆ nanosheets vertically grew on the Bi₂O₃ rods along the long axial direction. The photocatalytic activity required to degrade Rhodamine B (RhB) and phenol under solar/visible light by p–n junction of Bi₂O₃–Bi₂WO₆ nanorods was investigated. The results demonstrate that the novel Bi₂O₃–Bi₂WO₆ p–n heterostructures display higher photocatalytic activity than single Bi₂O₃ nanorods or Bi₂WO₆ flowers. The enhancement of the photocatalytic activity of the Bi₂O₃–Bi₂WO₆ p–n junction structures can be ascribed to strong visible light absorption and the effective separation of photogenerated electrons and holes by the internal electrostatic field in the junction region. More importantly, 1D p–n heterostructures made of ordered nanosheets are beneficial for the transport of photogenerated carriers and for increasing the rate of the photocatalytic reaction. This work could offer a new insight into the design and fabrication of advanced materials with heterojunction structures for photocatalytic applications and optoelectronic devices.