Fabrication of novel p-BiOI/n-ZnTiO3 heterojunction for degradation of rhodamine 6G under visible light irradiation.

With the purpose of efficient electron-hole separation and enhancement of photocatalytic performance in the visible region, we have fabricated a novel p-BiOI/n-ZnTiO3 heterojunction by a precipitation-deposition method and studied its activity toward dye degradation. The physicochemical characteristics of the fabricated BiOI/ZnTiO3 heterojunctions were surveyed by powder X-ray diffraction pattern (PXRD), BET-surface area, diffuse reflectance UV-vis (DRUV-vis), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), photoluminescence spectroscopy (PL spectra), X-ray photoelectron spectroscopy (XPS), and photoelectrochemical measurement. The photosensitization effect of BiOI enhanced the spectral response of ZnTiO3 from UV to visible region, making all the BiOI/ZnTiO3 heterojunctions active under visible light. The PEC measurement confirmed the p-type character of BiOI and n-type character of ZnTiO3. The optimal amount of BiOI in BiOI/ZnTiO3 heterojunctions was found to be 50% which degraded 82% of 50 ppm Rh 6G under visible light irradiation. The degradation rate of 50% BiOI/ZnTiO3 heterojunction was found to be 9.8 and 11.1 times higher than that of bare BiOI and ZnTiO3, respectively. The photosensitization effect of BiOI and the formed heterojunction between p-type BiOI and n-type ZnTiO3 contribute to improved electron-hole separation and enhancement in photocatalytic activity.