Synthesis Of Low-dimentional Bi₂WO₆-based Heterostructured Nanomaterials And The Photocatalytic Performance

Bismuth tungstate?Bi₂WO₆?,a perovskite-like structure consisting of the alternating bismuth oxide [Bi₂O₂]²⁺ layers and [WO4]2-octahedral layers,has the intrinsic visible-light absorption ability.The conduction band?CB?of Bi₂WO₆ is constituted of the W 5d orbital and its valence band?VB?is composed of the hybridization of the O 2p and Bi 6s orbitals,which can result in a narrow band gap.Although considerable research concerning Bi₂WO₆ photocatalysts has been done and a great progress has been achieved,the photocatalytic performance of the single-phase Bi₂WO₆ materials is still restricted by the fast recombination of the photo-generated electron/hole.The construction of photocatalytic heterojunctions,combining two semiconductors with the appropriate band edges,has therefore been a significant approach to overcome the serious drawback of fast charge recombination.1.The In₂O₃/Bi₂WO₆ heterostructured microbelts with the diameters around 300-500 nm have been fabricated by electrospinning combined with annealing process.We found that the In₂O₃/Bi₂WO₆ microbelts reported here show the well-defined morphology.Additionally,the In₂O₃/Bi₂WO₆ heterostructured microbelts exhibit the enhanced photocatalytic activity under the simulated sunlight irradiation compared with Bi₂WO₆ microbelts.2.One-dimensional?1D?CeO₂/Bi₂WO₆ heterostructured nanofibers with the diameter of about 300 nm were successfully synthesized by using a straightforward strategy combining an electrospinning technique with a sintering process.The obtained CeO₂/Bi₂WO₆ heterostructured nanofibers exhibited an excellent photocatalytic property for the degradation of Rhodamine B?RhB?dye driven by the visible light due to the promoted separation of photoelectrons and holes and large contact area between photocatalysts and organic pollutants.3.The one-dimensional?1D?ZnO/Bi₂WO₆ heterostructured sub-microbelts with the diameter of about 500 nm have been successfully synthesized by combining electrospinning technique with sintering process.Characterized by the TG-DSC,FT-IR,SEM,TEM,XRD,XPS,BET and UV-vis spectroscopy,the samples present an admirable morphology and excellent stable and recyclable photocatalytic property of degradation of RhB driven by the UV-visible light on account of the promoted separation of photoelectrons and holes and more active sites.The mechanism of synthesis and photocatalytic reaction of ZnO/Bi₂WO₆ heterostructured sub-microbelts have also been elaborated in this work.4.The one-dimensional?1D??-Fe₂O₃/Bi₂WO₆ heterostructured nanofibers with the diameter of about 300-500 nm were successfully prepared by using a simple and straightforward protocol combining an electrospinning technique with a sintering process.It was found that the construction of ?-Fe₂O₃/Bi₂WO₆ heterostructures can effectively impede the recombination of photoelectrons and holes and ?-Fe₂O₃/Bi₂WO₆ heterostructured nanofibers possess a superior photocatalytic activity compared to the pure Bi₂WO₆ nanofibers for the degradation of methylene blue?MB?dye driven by the visible light.5.One-dimensional?1D??-Fe₂O₃/Bi₂WO₆ heterostructured nanotubes with the diameter of about 300 nm were successfully synthesized by using direct strategy combining an electrospinning technique with a sintering process.The heterostructured nanotubes are made up of Bi₂WO₆ nanosheets and ?-Fe₂O₃ nanoparticles and this kind of novel morphology is responsible for the large specific surface area which can improve the visible light photocatalytic performance.The ?-Fe₂O₃/Bi₂WO₆ heterostructured nanotubes exhibit a highly improved photocatalytic performance compared with the pure phase Bi₂WO₆ materials for the degradation of Rhodamine B?RhB?dye driven by the visible light.In conclusion,this study mainly focused on researching the photocatalytic property of the Bi₂WO₆ heterostructured nanomaterials prepared by an electrospinning technique and a sintering process.And the photocatalytic performance of products were tested and compared by degradation of MO,MB and RhB.In addition,cycling experiments were also tested to discuss their stability,retrievability and recyclability.Moreover,the mechanism of synthesis and photocatalytic reaction has also been discussed in detail.