| Summary: | 碩士 === 國立中正大學 === 化學工程研究所 === 101 === This study was divided into two parts, first part of study is formation of Carbon nanofibers (CNFs) by different catalyst system (Ni/Al and Ni/Cu) for a calcinations process. Metal nitrate was used as catalyst precursor and mixed with PEG and DI water and calcined at air environment with a desired temperature. CNFs were synthesized by polymer pyrolysis method. The mixture as reactant was prepared by a mixture of PEG and HCl, which were employed as carbon source and promoter, respectively. Different types of CNFs such as platelet graphite nanofibers (PGNFs) and turbostratic CNFs were synthesized with different catalyst systems. It was found that the diameter of CNFs was changed by controlling the reaction temperature.
Graphene quantum dots (GQDs) were derived from PGNFs by liquid-phase exfoliation method. The structure of PGNFs was graphene nanosheets stacked perpendicular along the fiber axis. The organic solvent dimethyl sulfoxide (DMSO) was used which the surface tension is able to overcome the van der waals force between graphene layers. Characterization of GQDs by TEM, AFM, XPS and Raman spectrum, was conducted. According to characterization results, the diameter distribution of GQDs was about 11-27 nm and less than 5 layers. Low amount of oxygen group on GQDs surface was observed by XPS. This study was first time to derive GQD from PGNFs by liquid-phase exfoliation method. The size of GQDs can be effectively controlled by the use of PGNFs as starting materials.
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