S-scheme Bi/Bi2WO6/TiO2 nanofiber photocatalyst for efficient degradation of sulfamethoxazole

Improving the efficiency of photogenerated carrier separation by designing heterojunction photocatalysts remains an important challenge. In this study, TiO2 nanofibers were prepared by electrospinning, Bi/Bi2WO6/TiO2 heterojunctions were constructed by hydrothermal method, and verified by characterization techniques. The heterojunction had good photodegradation activity to sulfamethoxazole (SMX) under ultraviolet and visible light irradiation (96.4 % within 60 min). The enhanced photodegradation activity of Bi/Bi2WO6/TiO2 nanocomposites can be attributed to the synergistic effect of S-Scheme mechanism and Bi metal plasma action. In addition, Bi metals can generate a large number of electron-hole pairs under the action of surface plasmon resonance (SPR). In addition, the influence factors such as pH, SMX concentration and catalyst loading were studied. According to the detected intermediates, the photocatalytic degradation pathway of SMX was studied. The results of free radical capture experiment and ESR show that & sdot;O2- and h+ free radicals play an important role in the decomposition of SMX. The cyclic experiments show that Bi/Bi2WO6/TiO2 nanocomposites have excellent stability and reuse characteristics. Finally, the mechanism of photocatalytic degradation of SMX was described. This study provides a promising perspective for the preparation and development of S-Scheme heterojunction photocatalysts based on Bi2WO6.