Synthesis Of Phthalocyanine And Porphyrin Modified Bismuth Oxybromide Catalyst With Enhanced Photocatalytic Activities

Clean water is a precious resource to promote the production and livelihood of human.However,human behavior has resulted in serious water pollution that include traditional heavy meatal to varied organics.It is greatly urgent to deal with water pollution.Therefore,a more efficient and sustainable environmental technique is highly desired to solve water pollution.Photocatalysis emerged as a novel decontamination method with multi-advantages like strong mineralizing ability,low energy consumption and facile operation.Among various photocatalysts,bismuth oxyhalides?BiOX,X=Cl,Br,I?possess layered structure which features[Bi₂O₂]slabs interleaving double slabs of halogen atoms,thus constructed internal static electric fields facilitating charge transfer.In addition,the well stability,green and nontoxic properties make them promising photocatalysts.However,reducing recombination of electron-hole pairs and widening the absorption range of light are still two key issues to further improve the photocatalytic performance of bismuth oxyhalides.Herein,the enhanced charge separating and transferring efficiency and broadened light utilization range were obtained by modifying BiOBr with phthalocyanine and porphyrin.This thesis mainly deals with the following three parts:1.Iron phthalocyanine?FePc?possess good stability and visible light responsive ability.The iron phthalocyanine/bismuth oxybromide?FePc/BiOBr?composite catalyst was in situ constructed with room temperature self-assembly method.The morphology,structure and ingredient of the material were characterized by X-ray powder diffraction?XRD?,scanning electron microscope?SEM?,transmission electron microscope?TEM?,X-ray photoelectron spectroscopy?XPS?,Fourier transform infrared spectrometer?FT-IR?and Raman spectrometer.The photocatalytic performance was evaluated by removal of tetracycline?TC?and ciprofloxacin?CIP?.BiOBr and 0.5 wt%FePc/BiOBr degraded 63.6%and 68.6%TC within 120 min respectively,while 24.4%and 54.4%CIP was removed after 4 h.The degradation efficiency on TC and CIP of 0.5 wt%FePc/BiOBr increased by 5% and 30% respectively compared to bare BiOBr.Photoelectrochemical analysis revealed that the introduction of FePc could broaden the light absorption range and facilitate photogenerated carries separating and transferring efficiency of the composite catalyst.The reactive material was verified by electron spin resonance?ESR?and free radical trapping experiments.A possible photocatalytic mechanism was proposed.2.Tetraphenyl porphyrin?TPP?with simple chemical structure is easy access to sources,while possessing good stability and visible light absorption as well.TPP was tightly combined with BiOBr throgh solvothermal method to in situ construct TPP/BiOBr composite catalyst.The morphology,structure and ingredient of the catalyst were comprehensively characterized.The photocatalytic degradation test showed that BiOBr and 1 wt%TPP/BiOBr eliminated 50.3%and 73.5%TC within120 min respectively,while 41.6%and 56.5%CIP was degraded after 4 h.The degradation efficiency on TC and CIP of 1 wt%TPP/BiOBr increased by 23.2%and14.9%respectively compared to bare BiOBr.The introduction of TPP could extend the light absorption range of composite catalyst and facilitate carries separating and transferring.The reactive material was verified by ESR and free radical trapping experiments.A possible photocatalytic mechanism was proposed.3.Teracarboxyphenyl porphyrin?TCPP?possess polarized substituent carboxyl which bring better charge separation ability.TCPP/BiOBr composite was in situ constructed by room temperature self-assembly method.The morphology,structure and ingredient of the material were comprehensively characterized.The photocatalytic degradation test revealed that BiOBr and 0.5 wt%TCPP/BiOBr degraded 46.6%and74.7%TC within 120 min respectively,while 37.2%and 67.5%CIP was removed after 4 h.The degradation efficiency on TC and CIP of 0.5 wt%TCPP/BiOBr increased by 28.1%and 30.3%respectively compared to bare BiOBr.The introduction of TCPP effectively improved visible light responsive ability and charge separating and transferring efficiency of composite catalyst.The reactive material was verified by ESR and free radical trapping experiments.A possible photocatalytic mechanism was proposed.In this thesis,the modification of BiOBr with phthalocyanine and porphyrin simutaniously broaden light absorption range and enhance charge separation efficiency,which provided a novel idea on modifying semiconductor photocatalyst and enhancing photocatalytic performance.