The Modification Of The Cotton Nanofiber And ZnO Composites And Its Photocatalytic Performance

ZnO nanomaterials have been focused by many researchers extensively due to its better photosensitiveness and low cost.But there are two problems in the using of ZnO: The one is that it is powder crystal and easy to agglomerated,so it is difficult to recycle.The other is that it could be only activated by UV light and can not use the solar energy more effectively.The cotton fibers with low cost and easy to get,besides,the cotton nanofibers obtained by electrospinning tehnique with higher surface volume value and the structure of many hydroxyl,so it could provide large numbers of favorable coordination active sites,which could promote to disperse the catalyst in solution and improve the photocatalysis efficiently.On the other hand,narrow band gap materials?CuS ? Ag₃PO₄?and carbon quantum dots with up-converted photoluminescence behavior are chosed to modified semiconductor.The aim is to expand its light response range to the visible light region and use the solar energy more effectively.In this thesis,we mainly discussed the modification of cotton nanofibers/ZnO nanocomposites and its photocatalytic properties.Based on the above,the main works of this thesis focused on the following three aspects:1.Preparation and photocatalytic properties of the cotton nanofibers/ZnO/CuS nanocompositesIn order to to increase specific surface area and provide a mass of reaction site,cotton nanofibers were obtained by electrospinning process,and the diameter between 100²00nm.ZnO seed layer was get by the way of drop-coating,Then ZnO nanorod had been achieved by hydrothermal synthetic method.In order to expand its light response range to the visible light region,we had deposited the CuS nanoparticles?the diameter between 100²00nm.?on the ZnO nanorods sureface by the successive ionic layer adsorption reaction to obtain the cotton nanofibers/ZnO/CuS nanocomposites successfully.The visible light photocatalytic performance of this composite enhanced from 10% to 97% compared with unmodified sample.The results of XPS indicate that the it mainly attributed to the unique direct interfacial charge transfer behaviour of the Cu+.2.Preparation and photocatalytic properties of the cotton nanofibers/ZnO/Ag₃PO₄nanocompositesIn order to expand its light response range to the visible light region,Ag₃PO₄ nanoparticleswere deposited on cotton nanofibers/ZnO by ordinary precipitation method,the cotton nanofibers/ZnO/Ag₃PO₄ nanocomposites was successfully maked.Experimental demonstrate that the composites had better photocatalytic activity and stability,and visible light photocatalytic performance of this composite significantly enhanced from 10% to97% compared with pure nanofibers/ZnO.Which was attribute to ZnO/Ag₃PO₄ heterostructure structure,it can help to excite and separate the photogenerated electron-hole pairs for increasing the photocatalytic property.3.Preparation and photocatalytic properties of the cotton nanofibers/ZnO/carbon quantum dot nanocompositesUsing sucrose as carbon source,carbon quantum dots were prepared by hydrothermal synthetic method.Then carbon quantum dots were deposited on cotton nanofibers/ZnO by direct coupling method.The visible light photocatalytic performance of this composite enhanced from 10% to 93% compared with unmodified sample.the up-converted PL spectra of CQDs obvious indicate that the up-converted emission is located in the range of 380 nm which is attribute to the up-coverted photoluminescence behaviour of carbon quantum dots.Cotton nanofibers/ZnO nanocomposites hold very attrative properties such as photoelectricity,physical,chemical performances,and potential applications in photocatalyst,photoelectric display,self-cleaning material and smart clothing.