Research On Fabricating Efficient Visible Light Respnsive UiO-66（NH₂）-based Photocatalyst And Its Photocatalytic Performance On Pollutants Removal

Semiconductor photocatalysis,an emerging and eco-friendly technology,has aroused intensive attention for its potential applications in environmental remediation.Currently,many MOFs and MOFs-based materals have been used as photocatalysts in solving environmental problems.UiO-66（NH₂）is a fascinating visible-light responsive amino functionalized zirconium-MOF.However,its photocatalytic performance is less satisfactory because of the disappointing separation rate of electron-hole pairs and the poor solar energy utilization ability.Besides,antibiotics threaten the balance of ecosystem and human health because of the wide application and the discharge of antibiotic wastewater.Therefore,this research aimed at fabricating heterojunction between UiO-66（NH₂）and other semiconductor to improve the photocatalytic performance of UiO-66（NH₂）and the synthesized photocatalysts were emplyed in tetracycline（TC）removal.In the first section,an unique AgI/UiO-66（NH₂）heterojunction was constructed via a facile precipitation method to reinforce the photocatalytic performance of UiO-66（NH₂）.The physical properties,stuctures,chemical composition,optical properties and electrochemical properties of the prepared photocatalysts were characteired and discussed.In the second section,the photocatalytic performance was evaluated by degrading tetracycline under visible light.Besides,various photocatalytic reaction impact factors including the initial TC concentrations,reaction p H and co-existing substances were studied.The detailed intermediates and pathway of TC degradation were also illustrated and the possible photocatalytic mechanism was proposed.Conclusions showed that AgI/UiO-66（NH₂）composites owned enlarged optical adsorption ability and better electrochemical properties.Fabricating hetereojunction between Ag I and UiO-66（NH₂）ameliorated the photocatalytic performance of UiO-66（NH₂）.The optimal TC removal rate was obtained by Ag I（30%wt）/UiO-66（NH₂）which was 3.8-fold of UiO-66（NH₂）and 2.1-fold of Ag I.AgI/UiO-66（NH₂）composites presented excellent photostability and reusability.h⁺and·O₂^-were the mainly active species during the photocatalytic process.According to the results of characterization,it was determined that Ag nanoparticles（small amount）were occurred in the initial stage of photocatalytic process,which resulted in the transformation from AgI/UiO-66（NH₂）type II heterojunction to Ag I/Ag/UiO-66（NH₂）Z-scheme heterojunction.Benefting from the synergetic effects of novel heterojunction,considerable active sites,the depressed recombination of electron-hole pairs and the Surface Plasmon Resonance（SPR）Ag,AgI/UiO-66（NH₂）composites exhibited satisfied photocatalytic performance and the photocorrosion of Ag I was signifcantly suppressed.Our research illustrated a new way to design efficient UiO-66（NH₂）-based photocatalysts and widen its application in envrionmental remediation.