Construction of BiOI/TiO2 flexible and hierarchical S-scheme heterojunction nanofibers membranes for visible-light-driven photocatalytic pollutants degradation

Water was the source of life, in order to solve the serious water pollution problem facing the world, researchers have proposed many solutions. Among them, photoelectric catalytic technology based on semiconductor materials was an ideal and sustainable solution. Herein, by combining successive ionic layer adsorption and reaction (SILAR) with sol-gel electrospinning two strategies, a novel S-scheme heterojunction based on flexible and hierarchical BiOI/TiO2 nanofibrous membranes (BiOI/TiO2 NFM) was fabricated. The degradation rates of tetracycline (TC) and Rhodamine B (RHB) were 98.7% and 95.6%, respectively, under visible light irradiation. The main reason, except for the benefits offered by the hierarchical nanofiber structure, such as the large surface area, tightly connected interfaces and more exposed active sites, other advantages derived from photogenerated carrier transfer and superior redox ability were also momentous. To reveal the formed S-scheme heterojunction, a variety of test methods were used to characterize and test. These studies showed a significant increase in charge separation efficiency in the BiOI/TiO2 NFM, and the charge transport of S-scheme heterojunction was demonstrated. This study may offer new design ideas for the design and construction of novel structures of S-scheme heterojunctions.