Morphology modulation and performance optimization of nanopetal-based Ag-modified Bi2O2CO3 as an inactivating photocatalytic material

One-pot synthesis of 2D Ag/BiOCl/Bi2O2CO3 S-scheme heterojunction with oxygen vacancy for photocatalytic disinfection of Fusarium graminearum in vitro and in vivo

2D Ag/BiOCl/Bi₂O₂CO₃ S-scheme heterojunction was prepared with oxygen vacancy (OVs) via one-pot hydrothermal method. The XRD and XPS analysis indicated the synthesized sample contained Ag nanoparticles (AgNPs) instead of Ag ions. The SEM and HRTEM pictures showed that BiOCl/Bi₂O₂CO₃ nanosheets were modified with AgNPs. Compared with AgNPs, BiOCl, and Bi₂O₂CO₃, Ag/BiOCl/Bi₂O₂CO₃ exhibited highly photocatalytic inactivation of pathogenic fungi (Fusarium graminearum) due to the wide light absorption range and S-scheme heterojunction structure, which improved the production and transfer of photogenerated carrier, and enhanced the separation of photogenerated e-/h⁺ pairs. In addition, the improved photocatalytic disinfection against Fusarium graminearum of Ag/BiOCl/Bi₂O₂CO₃ was verified in Sedeveria Letizia plant. Furthermore, active species capture assay and ESR experiments disclosed the involvement of OVs, h⁺, ∙O₂^-, ∙OH, and ^-for Fusarium graminearum destruction during photocatalysis process. The S-scheme heterojunction was proved via oxygen vacancy, which was extensively beneficial to increase charge transmission and separation efficiency. Our work proposed Ag/BiOCl/Bi₂O₂CO₃ was an efficient and ecological fungicide to inactive Fusarium graminearum in vitro and vivo for crop disease.

Fabrication of g-C3N4@Bi2MoO6@AgI floating sponge for photocatalytic inactivation of Microcystis aeruginosa under visible light

In this work, a floating photocatalyst was constructed by loading g-C₃N₄@Bi₂MoO₆@AgI (GBA) nanocomposite on a modified polyurethane sponge via a simple dip-coating method and applied for the inactivation of Microcystis aeruginosa under visible light. GBA ternary photocatalyst was fabricated successfully and the morphology, structure, chemical state, and optical properties were characterized systematically. The floating catalyst achieved near 100% removal efficiency of algae cells under 6 h visible light irradiation and also could be retrieved and used at least three times repeatedly. The influences of various conditions on photocatalytic performance such as loading content of nanoparticles, algae density, and concentration of natural organic matters were also studied, which revealed that the GBA floating catalyst exhibited excellent photocatalytic performance of algae removal under different conditions. Furthermore, the physiological characteristics of algae cells during the photocatalytic process, including cell morphology, membrane permeability, Zeta potential, photosynthetic system, antioxidant system, and the metabolic activity were investigated. Results confirmed that the algae cells were severely damaged during the photocatalytic inactivation and the normal physiological functions were significantly affected, which resulted in the death of algae cells at last. Finally, a possible photocatalytic inactivation mechanism of algae cells was proposed. In summary, GBA floating catalyst can effectively inactivate Microcystis aeruginosa under visible light, which confirmed the high efficiency of the novel photocatalytic algae removal technology. Meanwhile, the recyclable floating material also makes the practical application in eutrophic waters of the algae removal technology possible.