Preparation And Applications Of Graphene Oxide Based Nanofibrous Membranes

In today's society,environmental pollution is immensely serious and lacking of energy has become one of significance global problems.Therefore,seeking simple and efficient approaches to take the charge of the environmental pollution and developing new energy store materials are the hot topics in the modern research fields.Semiconductor photocatalysts with unique performances show great potential in terms of governance environment.Generally,semiconductor photocatalysts have the wide band,thus,they just can be induced by a strong light energy.In order to make full use of light energy,researches on new semiconductor photocatalysts have been absolutely popular among the researchers.Furthermore,the current photocatalysts are powder-like with high surface energy that will lead to make less use and hard to recycle of the photocatalysts,which makes the waste of photocatalysts.Besides,the current electrode materials have low power density,low conductivity and poor reuse.This dissertation focuses on the preparation of semiconductor photocatalysts and electrode materials based on graphene oxides.The main contents are as follows:1.Freestanding materials prepared from chemically derived graphene have considerable potential as a carbon based catalyst in high performance flexible catalytic reaction.Herein,a highly flexible graphene membrane assembled from graphene oxides?GO?with the aid of polyacrylamide?PAA?and electroless deposition of gold nanoparticles?AuNPs?was prepared.In contrast to previous reports on GO based on a flow-directed assembly of graphene sheets,this GO/PAA/Au composite membrane exhibited a highly wrinkled and disordered morphology.The resultant GO/PAA/Au composite membrane was applied as catalytic material for the reduction of 4-nitrophenol and showed the favour separation,recovery,and cyclic utilization properties.2.Graphene oxide/polyacrylonitrile?GO/PAN?composite nanofibrous membranes were firstly prepared by an electrospinning method.Then,the GO/PAN composite nanofibrous membranes were further transferred to graphene oxides/carbon nanofibrous membranes?GO-CNFs?by a calcination treatment.Following a solvothermal treatment,zinc sulfide?ZnS?nanopartciles were covered onto GO-CNFs to form electrospun carbon nanofibrous membranes loaded with GO/ZnS?GO/ZnS-CNFs?.The composition and microstructure of GO/ZnS-CNFs were characterized by field emission scanning electron microscopy?FE-SEM?,X-ray photoelectron spectroscopy?XPS?,transmission electron microscopy?TEM?,Raman and UV-vis diffuse reflectance spectra analysis.Due to the synergistic effect between photocatalytic activity of ZnS and excellent adsorption capacity of GO-CNFs,the resultant GO/ZnS-CNFs exhibited excellent photocatalytic activity for oxidation of p-aminotoluene and phenol under mild conditions.The resultant hybrid carbon composite membranes offer the significant advantages,such as low dosage,high catalytic activity,easy recycling and excellent stability.3.Electrospun carbon nanofiber composites?ZnCo₂O₄/Ag-GO-CNFs?coated with 3D urchin-like ZnCo₂O₄ nanosheets to form a shish-kebab structure have been prepared using a combination of electrospinning,carbonization and hydrothermal treatments.The composition and microstructure of ZnCo₂O₄/Ag-GO-CNFs were investigated using field emission scanning electron microscopy?FE-SEM?,X-ray photoelectron spectroscopy?XPS?,transmission electron microscopy?TEM?,X-ray diffraction?XRD?and Brunauer-Emmett-Teller?BET?analysis.Interestingly,ZnCo₂O₄/Ag-GO-CNFs provided a new style of electrode materials and exhibited an excellent specific capacity of 459.48 mA/h/g at 20 mV/s.Notably,the specific capacity of ZnCo₂O₄/Ag-GO-CNFs also exhibited a remarkable cycling stability,which holds great promise for practical applications in energy storage devices as a carbon-based electrode material.