TiO2@BiOCl-BiOI Heterostructure Photocatalyst for Efficient Removal of Congo Red Dye under Simulated Sunlight

TiO2@BiOCl-BiOI heterostructure photocatalyst with high photocatalytic activity was prepared by the composite modification and sol-gel procedure. TiO2 nanoparticles highly dispersed on the surface of TiO2@BiOCl-BiOI, which provides sufficient active sites for the photocatalytic degradation process. The photodegradation performance of the photocatalyst was evaluated by the removal rate of Congo Red. The researches showed that the degradation effect of TiO2@BiOCl-BiOI for Congo Red is significantly stronger than that of TiO2 and BiOCl-BiOI, which is mainly due to the type-II heterojunction structure of TiO2@BiOCl-BiOI and its enhanced visible-light response. The experiments of free radical capture indicated that O-& sdot;(2)- and h(+) are the main active species in the photocatalytic degradation system. This study showed that TiO2@BiOCl-BiOI can almost completely degrade Congo Red under simulated sunlight, making it the harmless substances such as H2O and CO2.