Bi5O7I/Bi2O3: A novel heterojunction-structured visible light-driven photocatalyst

Novel Bi5O7I/Bi2O3 heterojunction-structured visible light-driven photocatalyst was prepared via chemical etching of Bi2O3 obtained by chemical precipitation method. The X-ray diffraction patterns confirmed the formation of Bi5O7I. The UV-vis diffuse reflectance spectra indicated that the absorption edge of Bi5O7I/Bi2O3 composite was 632 nm, which shifted towards longer wavelength than Bi2O3. Besides, the separation efficiency of electron-hole pairs in Bi5O7I/Bi2O3 heterojunction was higher than in Bi2O3, as implied by the photoluminescence emission spectra. The photocatalytic activities of Bi5O7I/Bi2O3 composite and Bi2O3 were evaluated and compared through degradation of malachite green and the results showed that Bi5O7I/Bi2O3 composite had better activity than Bi2O3.