Novel onedimensional Bi2O3-Bi2WO6 p-n hierarchical heterojunction with enhanced photocatalytic activity

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 N-2-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)center dot 2H(2)O 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.