Studies Of Preparation Of Fe Doped MOFs Hybrid Materials And Visible Light Photocatalytic Properties

Photocatalytic technology has become an indispensable part of scientific research in the world,because it can efficiently use the clean and abundant solar energy.In order to solve the problems of energy shortage and environmental pollution caused by traditional chemical industry,it is of great significance to study the catalysts with good photocatalytic performance.Metal organic frameworks（MOFs）are a kind of semiconductor with multi-metal active sites and good photocatalytic material as well.MOFs always have wide band gap（Eg）,which results in the poor absorption of visible light in solar energy.In addition,the larger conjugated system of MOFs makes the separation efficiency of photogenerated charge worse,resulting in lower photocatalytic activity of MOFs.In order to improve the photocatalytic performance of MOFs,the Fe doping method was used to enhance the response of MOFs to visible light and the separation of photogenerated carriers.In this work,the method for the introducing of Fe into MOFs such as UiO-66 and MIL-101was studied to regulate the response of materials to visible light.Then,the formation of an effective heterojunction by the composite semiconductor materials was employed to furtherly increases the separation efficiency of photogenerated electrons and holes.The specific research included the following three parts:1.A series of nanocomposites of ZFeU-x（where x is the mass ratio of ZnIn₂S₄ to FeUiO-66）,was successfully prepared the loading of FeUiO-66 on the surface of ternary semiconductor ZnIn₂S₄ with the solvothermal method.The as-obtained nanocomposites were characterized by FT-IR,XRD,SEM,UV-vis DRS,N₂ adsorption and disorption analysis.Then,these nanocomposites were applied to the photodegradation of RhB under visible light irradiation.The result showed that the nanocomposite of ZFeU-x had the best photocatalytic activity was 99.6%.The effective heterojunction between the two components was formed by the loading of FeUiO-66 on the semiconductor of ZnIn₂S₄,which had a strong response to visible light.Thus,the composite photocatalyst of ZnIn₂S₄/FeUiO-66with good photocatalytic activity was obtained.2.A novel photoactive porous material of GR/FeMIL-101 based on graphene was successfully synthesized via simple hydrothermal method.The structural and optical properties of the GR/FeMIL-101 was analyzed by XRD,SEM,TEM,TGA,XPS,UV-vis DRS,FT-IR,PL and EIS methods.Subsequently,the photocatalytic performance for the selective oxidation of benzyl alcohol of GR/FeMIL-101 was evaluated under visible light irradiation.The results showed that the GR/FeMIL-101 nanohybrid had better photocatalytic performance than anyone of FeMIL-101 and the pristine MIL-101,the conversion rate of benzyl alcohol was 50%It was further found that the incorporation of Fe into the MIL-101caused valence fluctuations of Fe³⁺/Fe²⁺which improved the absorption of visible-light and increases the separation efficiency of photogenerated charges.In addition,the combination of FeMIL-101 and GR could further promote the transfer rate of electrons.The mechanism of the reaction revealed that·O₂^-was the dominating active specie in this reaction through active species trapping experiments.3.Based on the unique advantages of UiO-66,such as the large surface,the porous strueture,as well as the regular arrangement of Zr in the framework of UiO-66,the Fe-ZrO₂nanocomposites were successful prepared through the uniform adsorption of Fe³⁺into the pore of UiO-66 and the sequently temperature programming calcination of the precursor of Fe³⁺/UiO-66.The morphology and structure of the catalyst were characterized by SEM,XRD,XPS,N₂ adsorption and disorption,FT-IR and UV-Vis DRS.The electrochemical performance of the catalyst was analyzed by PL and EIS.Finally,the photodegradation of RhB solution by the catalysis of Fe-ZrO₂ was studied.The results showed that the degradation rate of RhB under visible light irradiation was 83%in 120 min with the catalysis of Fe-ZrO₂.The catalyst had a promising stability.The degradation rate of RhB could still reach 78% after three cycles.