Novel BiIO4/BiVO4 composite photocatalyst with highly improved visible-light-induced photocatalytic performance for rhodamine B degradation and photocurrent generation

A novel BiIO4/BiVO4 heterojunction photocatalyst has been successfully developed by a facile hydrothermal route for the first time. X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-vis diffuse reflectance spectra (DRS) were utilized to characterize the crystal structures, morphologies and optical properties of the as-prepared products. Under visible light irradiation (lambda > 420 nm), the BiIO4/BiVO4 composite exhibits much better photoelectrochemical performance for rhodamine B (RhB) degradation and photocurrent (PC) generation compared to pure BiIO4 and BiVO4. This significant enhancement on visible-light-driven photocatalytic activity should be ascribed to the formation of the BiIO4/BiVO4 heterojunction, which can result in the high separation and transfer efficiency of photogenerated charge carriers. It was verified by electrochemical impedance spectra (EIS). The active species trapping experiment demonstrated that h(+) play a critical role during the photocatalytic process, which is consistent with the supposed photocatalytic mechanism.