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

Abstract

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 (λ > 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.