Preparation,Characterization And Visible-light Photocatalytic Activities Of MIL-53(Fe)-based Composite Materials

In recent years,water pollution is now becoming a major obstacle for futher and sustainable economic and social development.Photocatalytic technology has attracted increasing attention due to its application in environmental pollution control and treatment.Metal organic frameworks(MOFs)as visible light catalytic materials have attracted wide attention because of their large specific surface area,regular and uniform pores.Simultaneously,silver-based semiconductors have become a hot topic in the field of photocatalysis owing to their higher quantum efficiency and narrower bandgap.However,silver-based semiconductors possess their low surface area and poor stability,limiting their large-scale application.Therefore,it is possible to develop the novel photocatalysts combining MOF and Ag-based semiconductor materials.According to the above summary,a series of composites based on MIL-53(Fe)have been prepared,and their photocatalytic properties have also investigated.Firstly,a series of AgI/MIL-53(Fe)composites have been prepared by using simple grinding method.These composites have been characterized by Scanning electron microscopy(SEM),X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FT-IR),UV-vis absorption spectra,X-ray photoelectron spectroscopy(XPS).Rhodamine B(RhB)was chosen as the target of degradation.The photocatalytic activity and photocatalytic mechanism of the photocatalyst were studied.The experimental results showed the enhanced photocatalytic activity of g-AgI/MIL-53(Fe)composites were obtained under visible light irradiation.In addition,the recycling experiment of photocatalyst was aslo investigated in detail.As a result,the photogenerated electrons and holes are efficiently separated between AgI and MIL-53(Fe),leading to the improvement of photocatalyric activity.By means of grinding approach,the composites would be explored more active sites,which could also account for the improved photocatalytic performance for RhB degradation.Moreover,the explored active sites can also enhance the adsorption capability of composites toward the organic pollutant.Secondly,a series of D-AgI/MIL-53(Fe)composites have been successfully prepared by chemical solution method.Simultaneously,the structure,physicochemical properties and photocatalytic properties of these composites have been characterized.The experimental results showed that the D-AgI/MIL-53(Fe)composites can effectively degrade rhodamine B(RhB)dye under visible light irradiation,and their performance was superior to the bare MIL-53(Fe)and AgI materials.The mechanism investigation showed that the superoxide radicals and holes were the main active species in the photocatalysis process,and the degradation process followed the pseudo first-order kinetic model.Finally,a series of g-Ag3PO4/MIL-53(Fe)composites have been successfully prepared by the simple grinding method.The composites were characterized by XRD,SEM,UV-vis DRS and electrochemical measurements.Simultaneously,RhB was taken as the target of degradation,and the photocatalytic activity of the composites was studied under visible light irradiation.The experimental results showed that g-Ag3PO4/MIL-53(Fe)-0.3 exhibits the improved photocatalytic activity.In addition,the visible light photocatalytic mechanism was also discussed.