Preparation And Performance Analyse Of Oligopyrene

Oligopyrene is an excellent carbonaceous oligomeric pitch, because of their potential for forming a liquid crystalline phase (i.e., mesophase) and highly fluorescent efficiency, this kind of pitches are attractive precursors for advanced carbon materials and a great fluorescent sensing material. In this study, oligopyrene and carbon/graphitic carbon nitride (C/C3N4) hybrids were synthesized by thermal polymerization. Then we studied the compositions, structures, fluorescence and electrochemical properties of the products. Main work is summarized as follow:1. In this study, two types of oligopyrene were produced,one oligopyrene produced through the catalytic polymerization of pyrene in the presence of hexamethylenetetramine, the other oligopyrene produced solely by the thermal polymerization of pyrene. The composition and molecular structure analysis show that hexamethylenetetramine has obvious catalysis on the thermal polymerization of pyrene and no residue in the final products. Then we use PVA as the modifier to alkylate the oligopyrene. The result shows that the dimer, trimer and tetramer can be alkylated. The pentamer molecular ion peaks were found by MALDI in N- PPIS. Fluorescent spectra shows that the solvent polarity has a great influence on the peak position and fluorescence intensity of oligopyrene. The nitromethane-quenched emission spectra shows that the extent of quenching is more significant in the N-PPCh.2?Nine carbon materials were synthesized by a simple one-step carbonization of oligopyrene or alkyl-oligopyrene with nano-CaCO3 as a template. Structure and morphology characterization demonstrated that: oligopyrene and alkyl-oligopyrene are graphitizable carbon and can be easily carbonized to form carbon material with layer structure, and alkyl-oligopyrene has a higher yield. With the increase of nano-CaCCO3, more regular pore shape, smaller pore and thinner graphite layer was obtained. The electrochemical test shows that the products possess higher rate performance than traditional carbon materials. This anodic performance improvement is probably due to the existence of pore spaces and thinner layers. The discharge capacity of O-c was 384.2 mAh/g under the high current density (1A/g).3?Thermal condensation of pyrene and melamine were carried out in a pressurized reactor and three different ratio of C/C3N4 hybrids (PMs) were received. The composition and structure in these materials have been characterized. The result shows that the C/C3N4 hybrids have graphitic layer structure and the graphitic layer is composed of PAH structure and polymeric C3N4 structure. The electrochemical performance shows that the specific capacity of PMs is significantly higher than conventionally used graphite anodes under small current density. For PM-1, the initial discharge capacity was 769.8 mAh/g, after 60 cycles under different current densities, its discharge capacity still remain 582.2 mAh/g.