Construction Of Bismuth-based Heterostructured Composites With Highly Improved Photocatalytic Antifouling Performances

In recent years,photocatalytic technology has become a hotspot because of its high efficiency,green,environmental protection,and nontoxic.Particularly,bismuth-based semiconductors have attracted much attention on account of their abundant resources,excellent response ability toward visible light and well photocatalytic activities.However,the application of bismuth-based materials is highly limited due to the rapid recombination of photogenerated carriers.Therefore,it is of great significance to further enhance the photocatalytic activities by various modified methods.At present,construction of heterojunction is the mainly modified method.In addition,the photocatalytic activity of bismuth-based materials can be effectively enhanced by utilizing the two-dimensional(2D)MoS₂ as the auxiliary photocatalyst.Therefore,in this paper,the MoS₂/BiVO₄,Bi OI/MoS₂ and Bi₂S₃/Bi₅O₇I composites were synthesised through facile hydrothermal methods,in-situ growth and ion exchange reaction.Moreover,to explore the microstructure,photoelectric properties and photocatalytic performance,lots of tests were conducted,for instance,the microstructure characterization,morphology observation,photoelectrochemical performance test,photocatalytic degradation of organic dyes and inactivation of Pseudomonas aeruginosa,and so on.Therefore,this study provides a new idea for modifying bismuth-based semiconductor and marine antifouling.The detailed research informations are listed as follows:(1)The Z-scheme MoS₂/BiVO₄(MBV)heterojunction composite was successfully prepared through a simple hydrothermal method,which possessed excellent photocatalytic antibacterial performances.During the reaction process,BiVO₄ grew in-situ on the surface of MoS₂,forming a spindlelike structure at last.Under the irradiation of visible light,MBV composites showed highly enhaced photocatalytic activities compared to that of pure MoS₂ and BiVO₄.Among the as-prepared MBV composites,MBV-4 could completely kill P.aeruginosa within 90 min.Besides,MBV showed a good stability and reusability.In addition,the photocatalytic mechanism was proposed according to the active radical capture experiment and ESR test.(2)Using MoS₂ as the precursor,BiOI nanosheets would grew in-situ grown on the surface of MoS₂ nanosheets by a simple hydrothermal method.Hence,the Bi OI/MoS₂(BMS)type II heterojunction composites with good visible light photocatalytic performance were obtained.The BMS heterostructure possessed a larger specific surface area and more active sites in the surface,leading to the rapid separation of photogenerated electrons and holes.Besides,the BMS composites exhibited highly efficient photocatalytic performances under visible light irradiation.Especially,the BMS-8 composite can completely degrade rhodamine B(Rh B)in 90 min and kill 99.99%of P.aeruginosa.Besides,BMS-8 showed a good stability and reusability.The photocatalytic mechanism was proposed based on the trap experiment of active groups and ESR test.(3)Bi₂S₃/Bi₅O₇I(BSI)p-n heterojunction composites with excellent photocatalytic performances were successfully prepared by an in-situ growth and ion exchange method.The formation mechanism of BSI heterojunction was deduced by analyzing the microstructure and morphology under different reaction time.With the excitation of visible light,the photogenerated electrons and holes would transfer rapidly,which enhanced the response ability to visible light and photocatalytic activity of BSI composites.All BSI composites showed excellent photocatalytic degradation and antibacterial ability.Especially,BSI-1could completely degrade Rh B and inactivate 99.99%of P.aeruginosa within90 min.Furthermore,the BSI composite showed good stability and reusability.The photocatalytic mechanism was proposed according to active radical capture experiment and ESR test.