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

Graphical In this paper, heterojunction photocatalyst TiO 2 @BiOCl-BiOI was successfully synthesized by composite modification method combined with sol-gel method, and it was applied to the degradation of CR. Thanks to the heterostructure structure, TiO 2 @BiOCl-BiOI showed excellent photocatalytic performance for CR under simulated sunlight, with a removal rate of 96.45 %. After 5 times of recycling, the removal rate of CR by TiO 2 @BiOCl-BiOI is still higher than 87 %. Under the action of ⋅O − 2 , h + and ⋅O, CR is oxidized to H 2 O, CO 2 and other harmless substances. TiO 2 @BiOCl-BiOI heterostructure photocatalyst with high photocatalytic activity was prepared by the composite modification and sol-gel procedure. TiO 2 nanoparticles highly dispersed on the surface of TiO 2 @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 TiO 2 @BiOCl-BiOI for Congo Red is significantly stronger than that of TiO 2 and BiOCl-BiOI, which is mainly due to the type-II heterojunction structure of TiO 2 @BiOCl-BiOI and its enhanced visible-light response. The experiments of free radical capture indicated that ⋅ and are the main active species in the photocatalytic degradation system. This study showed that TiO 2 @BiOCl-BiOI can almost completely degrade Congo Red under simulated sunlight, making it the harmless substances such as H 2 O and CO 2 .