To explore the charge separation behavior within the WO3, BiVO4, BiVO4/WO3 and Au/BiVO4/WO3 nanostructures, PL measurements were collected under the excitation wavelength of 325 nm and shown in Figure . There is only one wide and intense emission peak appearing at 460 nm in the spectrum of WO3. This peak was ascribed to the near band edge (NBE) transition of WO3 . Similarly, two broad emission peaks appeared in the spectrum of BiVO4. The peaks at 400 and 495 nm are associated with the deep level defects and NBE of the BiVO4, respectively 31 .