Integration of Bi nanoparticles with brown TiO₂ co-modified by Bi₂Fe₄O₉ and BiFeO₃: Double S-scheme photocatalysts towards degradation of pollutants

Recently, plasmonic photocatalysts fabricated using non-noble element of Bi have presented promising performances to tackle environmental and energy issues. Herein, we integrated Bi nanoparticles with brown TiO₂ (denoted as T_OX) co-modified by Bi₂Fe₄O₉/BiFeO₃ components to fabricate double S-scheme plasmonic photocatalysts through a one-pot hydrothermal route. The results showed that the optimum T_OX/Bi₂Fe₄O₉/BiFeO₃/Bi photocatalyst decomposed tetracycline about 36.1, 7.05, and 5.13 times superior than T_OX, Bi₂Fe₄O₉/BiFeO₃, and T_OX/Bi₂Fe₄O₉/BiFeO₃ samples, respectively. More importantly, the resulting plasmonic photocatalyst exhibited superior photodegradation activities against the removal of other antibiotics such as azithromycin and amoxicillin, and dyes such as methylene blue, malachite green, and rhodamine B upon visible light. The extraordinary performance of rationally designed plasmonic photocatalyst was devoted to more harnessing of visible light and boosting charge segregation among the components facilitated by double S-scheme heterojunctions. The scavenging studies exhibited the formation of ^•OH, ^•O₂⁻, and h⁺ reactive species over T_OX/Bi₂Fe₄O₉/BiFeO₃/Bi nanocomposite under visible light. Considering the high stability, facile fabrication procedure, excellent biocompatibility, and impressive performance of T_OX/Bi₂Fe₄O₉/BiFeO₃/Bi photocatalyst in destroying a wide range of contaminants in water, it is inferred that other impressive plasmonic photocatalysts-based on Bi can be designed and developed for effectively addressing the environmental issues upon visible light.