The suppression of expeditious complexation of photoexcited carriers and the enhancement of light harvesting are two extraordinarily momentous elements for boosting the catalytic activity of synthesized semiconductor photocatalyst. Herein, a sequence of visible-light-induced self-assembled flower-like spherical Bi 2 WO 6 /BiOBr S-scheme heterojunctions were successfully fabricated by two-step solvothermal process. The fabricated Bi 2 WO 6 /BiOBr hybrids possessed the splendid capacity to catalyze the degradation of bisphenol A (BPA) in water without the addition of surfactant compared to monocomponent photocatalyst. The optimized Bi 2 WO 6 /BiOBr (FBBH-16) possessed the most prominent photocatalytic activity, acquiring a conspicuous degradation efficiency of 91.97 % ± 1.51 % for BPA after 60 min illumination. The rate constant k (0.04078 ± 0.0009985 min −1 ) of FBBH-16, which was approximately 4.0 and 3.5 times that of bare Bi 2 WO 6 and BiOBr, respectively. Such strengthening mechanism was chiefly ascribed to the establishment of S-scheme heterojunction, which efficaciously impeded the complexation of photoexcited charge pairs and noteworthily heightened the light harvesting. Furthermore, the forceful interfacial interactions between Bi 2 WO 6 and BiOBr afforded much more active sites for BPA removal. The quenching experiments confirmed that ·OH and ·O 2− are the principal active species for BPA degradation over Bi 2 WO 6 /BiOBr hybrids. Ultimately, two possible photodegradation pathways of BPA over Bi 2 WO 6 /BiOBr heterojunctions are also come up with on the grounds of the identification of intermediate products. This work furnishes fresh insights into the fabrication of highly efficacious and stable bismuth-based S-scheme heterojunctions for treating the actual wastewater by integrating nanostructure and microscopic morphology.
Prostate cancer is one of the most common cancers in the world, and its early diagnosis can effectively reduce mortality. A new label-free photoelectrochemical (PEC) immunosensor on the basis of Bi 2 WO 6 /BiOBr nanocomposite materials has been successfully prepared for the test of prostate-specific antigen (PSA) in human serum in this work. The Ag 2 S-sensitized Bi 2 WO 6 /BiOBr heterojunction was used as a photosensitive material, which effectively improved the photocurrent response. On Bi 2 WO 6 /BiOBr surface, dopamine immobilized PSA antibody by self-polymerizing to form polydopamine membrane. Antigen and antibody are specifically combined to achieve quantitative detection of PSA according to the current changes at different concentrations of antigen. Under the optimal experimental conditions, the PEC immunosensor has an ideal linear relationship between 1 pg/mL - 50 ng/mL, and the detection limit is 0.084 pg/mL. In addition, the prepared immunosensor has good stability, reproducibility and selectivity, providing a new method for the detection of PSA in actual sample analysis.
Ternary Au/Bi2WO6/BiOBr composites were skillfully prepared via a two-step synthetic route. The two-component Bi2WO6/BiOBr heterojunction was firstly fabricated by hydrothermal method, and Au nanoparticles (NPs) were further introduced and uniformly anchored on the surface of Bi2WO6/BiOBr, where the loaded Au NPs could be beneficial for improving visible-light absorption and adjusting photoinduced charge carriers in the heterostructure through surface plasmon resonance (SPR). In comparison with pristine Bi2WO6 and two-component Bi2WO6/BiOBr, the ternary Au/Bi2WO6/BiOBr composite exhibits a better photocatalytic activity for removal of rhodamine B (RhB) under visible light irradiation. The degradation efficiency of GTB-3 composite 1.9 times higher than that of the pure Bi2WO6 and 1.24 times than that of Bi2WO6/BiOBr. Trapping tests with different scavengers revealed that not hydroxyl radicals but superoxide radicals and photogenerated holes were highly responsible for the degradation process. The enhanced photocatalytic activity was ascribed to the synergetic effect of heterojunction effect (efficient separation of charge carriers), porous structure of Bi2WO6 (strong adsorption), SPR of Au.
Chao Wang,Dayong He,Hui Zhao,Ce Wang,Kaizhong Wang
Levofloxacin is an emerging contaminant that threatens the aquatic organisms and human health. Bi 2 WO 6 -based heterojunction materials exhibit positive photocatalytic degradation activity under visible light with highly stable hierarchical nanostructures for levofloxacin remediation. However, recycling in practical applications is challenging. Herein, a hybrid nanofibrous film comprising BiOBr nanoplates on a layered Bi 2 WO 6 nanofiber was successfully synthesized using electrospinning, a solvothermal method, and successive ionic layer adsorption and reaction (SILAR). The size and quantity of BiOBr nanoplates grown on the fibers are controlled by adjusting the number of SILAR cycles. The BiOBr nanostructure obtained on the surface of the nanofibers controlled the photocatalytic activity of the sample. The resulting film exhibited superior degradation efficiency toward levofloxacin under visible-light irradiation due to its solid heterostructure, large specific surface area, high porosity, and enhanced visible-light response. The degradation efficiency of levofloxacin reached 95.25% after the system was exposed to visible light for 120 min, and five cyclic experiments demonstrated its excellent stability and reuesability. The Bi 2 WO 6 /BiOBr/polyacrylonitrile nanofibrous film provides a new strategy for developing high-tech equipment and other applications in environmental remediation.
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