Synthesis Of Bismuth Oxychloride Baesd And Bismuth Tungstate Baesd Composite Photocatalysts For Organic Pollutants Elimination

Photocatalysis technology has been widely using for organic pollutants elimination and novel energy manufacturing,which is deemed to the effective means for solving environmental contamination and energy crisis.Recently,bismuth photocatalyst as a new type of efficient photocatalyst show excellent photocatalytic performance in the degradation of organic pollutants,water splitting,reduction of carbon dioxide and heavy metal ions elimination under solar light.However,most of the bismuth photocatalyst reported at present remain many defects,such as,low solar energy utilization efficiency and fast recombination of photon-generated carriers,which limits the practical and large-scale application of bismuth photocatalyst.Therefore,the focus of research is supposed to improving the visible light absorption performance and enhancing the separation efficiency of e--h+ of bismuth photocatalyst.The efficient method for improving the photocatalytic performance can be ascribed to morphological control,structure of heterostructure and element doping.Different morphologies,such as,nanoplates,nanosheet,microsphere and quantum dots can be prepared by morphological control.Structure of heterostructure can improve the optical absorption property and promote the separation efficiency of photon-generated carriers.Element doping is confirmed as an effective way to adjust the band-gap energy of bismuth photocatalyst.The main content of this paper is the synthesis of bismuth oxychloride(BiOCl)nanosheet and microsphere and the synthesis of bismuth tungstate(Bi2WO6)nanosheet and flower-like microsphere with high specific surface area.After that,region-selective deposition process was used to prepare CdS QDs/BiOCl and Z-scheme CdS/CQDs/BiOCl heterojunction,an in-situ reduction and depositing process was adopted to prepare CdS QDs/Bi/Bi2W06 composite.The experiment results show that morphological control and structure of heterostructure obviously improved the photocatalytic activity of BiOCl and Bi2WO6.The research process and results of this paper are displayed as follows:1?Bi(NO3)3?5H2O and NaCl were used as precursor,solvothermal method was adopted to prepare BiOCl with different morphology.When the ethylene glycol(EG)was used as solvent,the product turns out to be BiOCl microsphere with size of 2-3 ?m.When the mixture of EG and deionized water(V=1:1)was used as solvent,the product turns out to be BiOCl nanosheet with width of 200-300 nm,thickness of 30 nm.The result indicates that the photodegradation ratio of rhodamine(RhB)in the presence of BiOCL microsphere and nanosheet with 43%and 41%exposed to visible light irradiation for 120 min.Besides,the photodegradation ratio of phenol in the presence of BiOCl microsphere and nanosheet with 43%and 41%exposed to UV light irradiation for 120 min.2?Polyvinylpyrrolidone(PVP K30)was used as surface modification agent,Bi(NO3)3·5H20 and Na2WO4·2H2O were used as precursor.Hydrothermal method was adopted to prepare Bi2WO6 nanosheet and microsphere by changing the addition of PVP.The result indicates that the specific surface area of Bi2WO6 nanosheet and microsphere is 15.96 m2/g and 6.35 m2/g.Under visible light irradiation,Bi2WO6 microsphere exhibits much better photocatalytic activity than that of nanosheet,which can be ascribed to the higher specific surface area of microsphere.2?BiOCl nanosheets and microsphere were used as supporter,CdS QDs was used as loaded reagent,region-selective deposition process was used to prepare CdS QDs/BiOCl composite.The results indicate that CdS nanoparticles with size less than 10 nm dispersed uniformly on the surface of cuboid BiOCl nanosheets.The deposition of CdS QDs improved the optical absorption properties of BiOCl nanosheets and the separation efficiency of electron-hole pairs.The photocatalytic performance tests reveal that CdS QDs-3%/BiOCl occupies the best photocatalytic activity,which is over 4.0 times as high as pure BiOCl for MO photodegradation rate under simulated solar light illumination.3?Bi(NO3)3·5H2O and NaCl were used as precursor,CQDs and CdS QDs were used as loaded reagent,step-wise region-selective deposition process was used to prepare Z-scheme CdS/CQDs/BiOCl heterojunction.The results indicate that CQDs with size of 2-5 nm and CdS nanoparticles with size of 5-10 nm dispersed uniformly on the surface of cuboid BiOCl nanosheets.Z-scheme CdS/CQDs/BiOCl not only improves visible light absorption and the migration efficiency of the photogenerated electron-holes but also keeps high redox ability of CdS/CQDs/BiOCl composite,owing the excellent electrical conductivity of CQDs.The photocatalytic performance tests reveal that the CdS/CQDs/BiOCl composite exhibits an excellent photocatalytic activity,the photodegradation ratio of 20 ppm RhB in the present at CdS/CQDs/BiOCl and pure BiOCl are 99%and 40%,under visible light for 50min.4?Flower-like hierarchical CdS QDs/Bi/Bi2WO6 heterojunction photocatalyst was synthesized by an in-situ reduction and depositing process.The results indicate that plasmonic Bi nanoparticles as the electron-conduction mediator with the size of 10 nm promote the charge transfer effectively between CdS nanoparticles and Bi2WO6 nanosheets.Besides,CdS QDs/Bi/Bi2WO6 composite exhibits an extraordinary enhanced photocatalytic activity than pure Bi2WO6,Bi/Bi2WO6 and CdS QDs/Bi2WO6 for Rhodamine B and formaldehyde photodegradation,respectively.