Modified Bismuth Molybdate And Its Visible Light Catalytic Performance

The misuse and overuse of antibiotics has entered many environment matrixes.Antibiotic resistant bacteria(ARB)and antibiotic resistance genes(ARGs)have already become one of the hotspots of current environmental problems.Due to its high energy availability,visible light photocatalytic technology has attracted much attention.Bismuth Molybdate(Bi₂MoO₆)possesses a unique layered structure and a relatively narrow band gap width that allows it to absorb visible light.Nevertheless,the practical application of Bi₂MoO₆is limited by its low quantum efficiency and utilization rates of sunlight.The use of ion doping and semiconductor compounding are effective ways to improve the performance of photocatalytic materials.Based on this,BMO is synthesized by solvothermal method,and the photocatalytic performance of BMO is further improved by the introduction of oxygen vacancies through Br doping and SPR effect of Ag,respectively.The common Escherichia coli(E.coli)and sulfamethazine(SM)in the environment are selected as model pollutants for antibiotic resistant bacteria and antibiotics,respectively,to evaluate the degradation and sterilization performance of the prepared photocatalysts.The degradation and sterilization mechanisms are described in combination with characterization methods.The main research contents and conclusions are as follows:(1)Taking BMO as the research model,we successfully construct oxygen-deficient Bi2MoO6 with concentration-adjustable OVs.In detail,BMO with different oxygen vacancy concentrations(BMO-Br)are synthesized via a facial Br-doped solvothermal approach.XRD,TEM and XPS spectra show that Br-doped significantly promotes the formation of surface oxygen vacancies.UV-VIS-NIR results reveal that oxygen vacancies enhance the visible light absorption of BMO.The photocatalytic sterilization and degradation results show that,compared with BMO,BMO-Br-4 could completely inactivate E.coli within 60 min,and degrade 80%SM within 150 min.The active species trapping experiments uncover that·O₂^-,·OH and h⁺play a major role in the sterilization and SM degradation.The PL,photocurrent and EIS results show that the introduction of oxygen vacancies is beneficial to the separation and transfer of photogenerated carriers.Finally,the photocatalytic sterilization and degradation mechanism of Br-doped oxygen vacancy BMO materials are deduced based on the characterization results of Mott-Schottky and VB XPS.(2)Taking BMO as the research model,a ternary Ag/Ag Cl/BMO plasmonic photocatalyst is successfully fabricated via a precipitation-photoreduction reaction.In detail,the co-modified Ag/Ag Cl/BMO photocatalyst is synthesized via a two-step process involving the precipitation of Ag Cl and photo-reduction of Ag on the BMO surface.TEM images show that the obtained BMO microspheres are composed of nanoplates,on the surface of which Ag/Ag Cl particles were distributed.It is found that Ag/Ag Cl/BMO photocatalyst exhibited higher photocatalytic disinfection and degradation activity under visible light irradiation than those of BMO and Ag Cl/BMO,Ag/Ag Cl/BMO could completely inactivate E.coli within 60min,and degrade 99.99%SM within 30 min.The active species trapping experiments uncover that·O₂^-play a major role in the sterilization and SM degradation.The photocatalytic mechanism of Ag/Ag Cl/BMO could be attributed to the excellent synergistic effect of Ag and Ag Cl,where plasmonic Ag nanoparticles promote light absorption and work as electron-transfer.