Construction Of PbBiO₂Cl Based Composite For Photocatalytic Removal Of Organic Contaminants

Since the reform and opening up,China's economic and social development has made remarkable achievements,but it has brought a series of problems such as energy shortage and environmental pollution.Consequently,photocatalysis technology,a new green advanced oxidation technology,is favored by many researchers because of its unparalleled advantages,and has become one of the research hotspots of researchers.The research and development of photocatalytic materials with high efficiency,green,easily available,stable and excellent performance is the key to realize the large-scale application of photocatalytic technology.In this paper,bismuth lead oxychloride?PbBiO₂Cl?photocatalytic nanosheets materials with perovskite structure were designed and synthesized by reactive ionic liquids and double solvent assisted solvothermal methods.Based on it,bismuth oxychloride lead oxychloride?PbBiO₂Cl?-based composite photocatalytic materials were prepared with zero-dimensional carbon quantum dots?CQDs?,one-dimensional carbon nanotube?CNTs?and two-dimensional molybdenum disulfide?MoS₂?,respectively.The photoabsorption range and carrier separation efficiency were broadened,and the photocatalytic performance of pollutant degradation was improved.The main contents of the study are as follows:Firstly,flaky perovskite-like PbBiO₂Cl photocatalytic materials and MoS₂nanosheets were synthesized using deionized water and anhydrous ethanol as solvents,respectively,and MoS₂/PbBiO₂Cl composites were constructed by compounding them.The composition,structure,morphology and photoelectrochemical properties of the composites were studied through a series of characterization.Rhodamine B?RhB?dye and antibiotic ciprofloxacin?CIP?were used to evaluate the photocatalytic activity of MoS₂/PbBiO₂Cl composites.The experimental results show that the introduction of MoS₂ can improve the photocatalytic degradation of pollutants,among which 1 wt%MoS₂/PbBiO₂Cl has the best photocatalytic degradation activity,which degrades about 76.78%RhB and 80.38%CIP in 120 min and 180 min,respectively.Finally,according to the activity data and the measured active species,the mechanism of photocatalytic degradation of pollutants by MoS₂/PbBiO₂Cl composites was given.Subsequently,one-dimensional CNTs material and PbBiO₂Cl were introduced to construct CNTs/PbBiO₂Cl composites.Among them,a wide range of delocalized?bonds on CNTs are formed by the P electrons of carbon atoms,which have a significant conjugation effect and are the same as the lamellar structure of graphene,hence CNTs have particular electrical properties and fantastic electrical conductivity.After compounding with PbBiO₂Cl monomer material,the separation efficiency of electron-hole pair can be effectively improved,thus the photocatalytic performance of CNTs/PbBiO₂Cl composites can be improved.It can be obtained from DRS characterization that CNTs/PbBiO₂Cl composites display stronger light absorption capacity.Moreover,the BET characterization indicated that CNTs/PbBiO₂Cl composites had a larger specific surface area and could better adsorb pollutants and reactive substances.The photocatalytic degradation of pollutants under visible light irradiation showed that the introduction of carbon nanotubes could effectively improve the performance of the composite photocatalytic degradation of rhodamine B?RhB?dye and tetracycline?TC?.5 wt%CNTs/PbBiO₂Cl materials showed the best photocatalytic activity.Radical capture experiments and electron spin resonance?ESR?studies showed that the active species in the photocatalytic process were holes?h⁺?and superoxide free radicals(O₂^·-).CQDs is a zero-dimensional carbon-based material with good dispersion and excellent photoelectrochemical properties.Loaded on the surface of photocatalytic materials,nanoscale heterostructures can be produced,which can effectively promote the separation of photogenerated electron-hole pairs and accelerate the interfacial charge transfer.On the basis of the above,CQDs/PbBiO₂Cl composites were synthesized by solvothermal method to further improve the photocatalytic performance of PbBiO₂Cl monomers.And it is proved that CQDs has been successfully loaded on the surface of PbBiO₂Cl nanowires through a series of characterization.Photocurrent and electrochemical impedance analysis showed that the separation efficiency of photogenerated electron-hole pairs in CQDs/PbBiO₂Cl composites was significantly increased after the introduction of quantum dots.The results of photocatalytic degradation of pollutants showed that CQDs/PbBiO₂Cl composite had remarkable photocatalytic activity for dye RhB,antibiotic CIP,TC and endocrine disrupting hormone bisphenol A?BPA?,and 3 wt%CQDs/PbBiO₂Cl composite had the best photocatalytic degradation activity.In addition,ESR and radical capture experiments proved that the active species in the photocatalytic reaction were h⁺and O₂^·-,and combined with the experimental activity data and the active species in the photocatalytic process,the possible photocatalytic mechanism was given.