Preparation And Properties Of Composites Based On Carbon Nanofibers

Carbon nanofibers (CNFs) are one-dimensional carbonaceousmaterials that are made up of nanosized graphene sheets stacked withdifferent orientations. Due to their unique nanostructure and excellentproperties, CNFs and CNFs-based nanocomposite materials have shownpromising applications in many fields, such as sensors, catalysts,electronics, lithium ion batteries, supercapacitors and hydrogen storageetc. In this thesis, on the basis of CNFs that have functionally treatedsurface, we prepared several kinds of nanocomposite materials bycompositing CNFs with transition metal hydroxides and transition metaloxides. Furthermore, the biosensing properties of these nanocompositeswere investigated. The main contents are given as follows:1. Using CNFs as the based material and NiCl.2, N2H4H2O andNH.3H2O as the reactants, the CNFs/Ni(OH)2nanocomposite wassynthesize with a reflux method. The nanocomposite was characterizedby scanning electron microscopy (SEM) and powder X-ray diffraction(XRD). The interfacial properties of the electrodes modified with pureNi(OH)2and with the nanocomposite were characterized byelectrochemical impedance spectroscopy. Cyclic voltammetric andamperometric methods were used to investigate the catalytic properties ofthe modified electrodes for glucose electrooxidation in alkaline solution.The sensor exhibited a wide linear range, a low detection limit, fastresponse time, high sensitivity, good reproducibility, and long operationalstability. Utilization of the nonenzymatic sensor for monitoring glucose inreal samples was also demonstrated.2. Using CNFs as the based material, NiSO4as the nickel source,and NH4HCO3as the pH modifier, the CNFs/NiO nanocomposite wasobtained with a stirring and calcination method. The morphology andstructure of the composite were characterized by SEM, XRD and transmission electron microscope (TEM). The preliminary study on theelectrochemical properties of the CNFs/NiO nanocomposite was alsocarried out.3. In the alkaline NaOH solution, with CNFs being the based material,Cu(Ac)2being the copper source, and L-ascorbic acid being the reductant,the CNFs/Cu2O nanocomposite was synthesized via a simple chemicalreduction route at room temperature. The morphology and structure ofCNFs/Cu2O were characterized by SEM, XRD and TEM. We found thatthe dosage of copper source influenced the size and distribution of theCu2O nanoparticles on the surface of CNFs.4. The CNFs/CuO nanocomposite was obtained with a simple refluxmethod by using CNFs and Cu(Ac)2as the source materials in theethanol-water system. The morphology and structure of the final productswere characterized by SEM, XRD and TEM. The results indicated thatthe ratio of the alcohol to water and the selection of the copper sourcehave a significant effect on the production of the nanocomposite.5. In the dimethyl formamide-water system, by using CNFs andMn(Ac)2as the starting materials, the CNFs/Mn3O4nanocomposite wassynthesized by a facile reflux route. The morphology and structure of thefinal CNFs/Mn3O4were characterized by SEM, XRD and TEM. Theresults showed that the amount of Mn(Ac)2can affect the final size andscattering of the Mn3O4nanoparticles.