Preparation And Photocatalytic Activities Of Agx Doped Bismuth Nanomaterials Catalysts

With the development of economy,human is in the pursuit of high quality life,as well as gradually pay attention to the current environmental problems.Semiconductor photocatalysis is gradually attracted the interest of the researchers owing to its unique properties in environmental purification.There are many methods to improve the performance of a photocatalyti,such as noble metal loading,ion doping,dye sensitization,semiconductor coupling,and so on.Especially,semiconductor coupling,which can improve the separation efficiency of carriers via the charge migration between the semiconductors,is considered as the most effective approach.Following this method,herein,we modified Bi5O7I,Bi3O4Br with AgX to synthesize three efficient semiconductor photocatalysts.The first part of the paper introduces the tentative work on the preparation of AgI/Bi5O7I composite wich nanostructures.Firstly,flower-like Bi4O5I2 were prepared by a hydrothermal method.Then,Agl was loaded on the substrate by an in situ deposition.Bi4O5I2 was finally converted to Bi5O7I by calcination at high temperature.The structure and morphology of the catalyst were characterized by X-ray powder diffraction(XRD),UV-vis DRS(scanning electron microscopy)and scanning electron microscopy(SEM).The results showed that the catalyst consisted of AgIand Bi5O7I with a morphology of flower-likeThe activity evaluation experiment showed that the prepared samples had high photocatalytic activity.In the second part of the paper,Bi5O7I microrods were prepared by a simple hydrothermal method,and AgI/Bi5O7I photocatalyst was prepared by an ion exchange method.The synthesized composite exhibits excellent photocatalytic activity under visible light irradiation.A series of characterizations were performed to investigate the structure and optics performance.The XRD and Raman analysis indicated that catalyst mainly contains of AgI and BisO7I.The XPS characterization indicated that there are a small amount of metallic silver nanoparticles in the catalyst.The composite catalyst is actually Ag-AgI-Bi5O7I ternary system.The synergetic effect between the three phases isthe origin of the high photocatalytic activity of the AgI/BisO7I composite.The third part of the paper introduces the work of AgBr/Bi3O4Br semiconductor photocatalyst.The photocatalyst is also prepared by ion exchange between AgNO3 solution and Bi3O4Br.The high activity and stability of the synthesized AgBr/Bi3O4Br in Rhodamine B(RhB)degradation under visible light irradiation were observed.When the AgBr content was 5%,the sample showed the highest photocatalytic activity.The degradation rate reached 0.032 min-1,which was 2.5 times of that of pure Bi3O4Br.The enhanced photocatalytic activity of the composite was ascribed to the coupling effect of Ag nanoparticles,AgBr and Bi3O4Br.