Preparation And Photocatalytic Performances Of One-Dimensional Nanocomposites Based On Electrospinning Approach

One-dimensional(1D)nanomaterials have been attracted numerous attentions due to their special properties,such as photoelectricity,physical and chemical performances,and potential applications in biological scaffold materials,hydrogen storage materials,photocatalysis and carrier materials.Compared with the traditional methods,the electrospinning technique seems to be a simple and effective to fabricate 1D nanomaterials.In this thesis,the hot issues about the rapid recombination of photo-generated electron-hole and the low quantum efficiency in photocatalysis are focused.Based on the 1D nanomaterials,a series of composite nanofibers photocatalysts from binary to polynary were designed and preparaed by an electrospinning approach associated with photo-deposition and hydrothermal/solvothermal method.The prepared 1D nanocomposites showed high photocatalytic activities and good performances.It was explored that the effects of their compositions,morphologies,microstructures,interface and charge transport on the photocatalytic properties.The details are briefly summarized as follows:(1)We had prepared CdS/TiO2 heterojunction nanofibers by a photodeposition method,based on the electrospinning TiO2 nanofibers.The samples showed excellent selectivities and conversion rates for catalytic oxidation of alcohols to aldehydes under visible light irradiation.The characterization results revealed that CdS nanorods were dispersed on the surface of TiO2 nanofibers.The close contact heterojunctions were observed at their interfaces.The enhanced photocatalytic activity could be attributed to the effective separation of the photogenerated electron-hole due to the formed heterojunction between CdS and TiO2.(2)A facile,rapid and efficient electrospinning mediated photodeposition method had been developed to prepare MoS2/CdS-TiO2 nanofibers.The MoS2/CdS-TiO2 nanocomposites showed much higher photocatalytic activitiy for H2 evolution than Pt/CdS-TiO2 nanofibers and MoS2/CdS-P25 composites under the same experiment conditions.The high activity can be ascribed as the close interfacial contact and the mutual synergistic interaction among the different components 1D TiO2,CdS and MoS2,greatly promoted the migration of photo-generated carriers.(3)Using TiO2 nanofiber as a support,the nanocomposites with Zno.5Cdo.5S nanoparticles well-dispersed on TiO2 nanofibers were prepared by the effectively control of Zno.5Cdo.5S growth using a solvothermal approach.Furthermore,a new type of RGO/Zn0.5Cd0.5S-TiO2 multicomponent catalyst was constructed via introduction of grapheme.The RGO/Zn0.5Cd0.5S-TiO2 composites showed good visible light photocatalytic property for H2 evolution from water because the separation efficiency of photogenerated charges was promoted by excellent electron transport property of RGO and the matching band structure between Zn0.5Cdo.5S and TiO2.(4)Using the electrospun SnO2 nanotubes as both supports and reactants,SnS2/SnO2 nanocomposites were fabricated by a hydrothermal method via in situ ion-exchange apporoach.The prepared SnS2/SnO2 nanocomposites showed much higher photocatalytic activity than single SnS2 nanoplates and their physical mixture for the reduction of Cr(VI)under visible light irradiation.The photoelectrochemical analyses indicate that the high photocatalytic activity could be ascribed to the rapid charge transfer between the composites interface.These composite photocatalytic materials composed of 1D nanofibers possess nanofibrous nonwoven web structure,showing good separation and recycling features.These are also key factors for photocatalytic practical application.