The synthesis of nitrogen doped carbon spheres and polythiophene/carbon sphere composites

• Main Author: Kunjuzwa, Nikiwe
• Format: Others
• Language: en
• Published: 2010
• Subjects: nanotechnology; chemical vapour deposition; nitrogen doping; electromagnetic spin resonance; polymerization; polythiophenes; functionalized carbon spheres; noncovalent functionalization; covalent functionalization; composites
• Online Access: http://hdl.handle.net/10539/7709

This study reports on the synthesis of N-doped carbon spheres (N-CSs) by a simple synthetic procedure. A horizontal CVD type reactor was used to synthesize N-CSs from pyridine. Depending on the dilution of the pyridine with toluene, a nitrogen content of 0.13-5 mol % was obtained. The use of a vertical CVD reactor gave N-CSs with a N-content of 0.19-3 mol % when an ammonium solution and acetylene were used as reactants. The diameters of carbon spheres were found to be in the range of 40 nm to 1000 nm for both CVD reactors. The diameter can be controlled by varying the flow rate, temperature, time, concentration and the reactor type. The samples were characterized by TEM, HRTEM, elemental analysis, Raman spectroscopy, TGA, PXRD and ESR. We have demonstrated that unsubstituted thiophene can be polymerized by Fe3+-catalyzed oxidative polymerization. The average particle size was about 50 nm, within a narrow particlesize distribution. The undoped carbon spheres (CSs) were reacted with thiophene to give polymer/carbon composites containing polythiophene and carbon nanospheres via chemical oxidative polymerization reaction. Polythiophene molecules were either chemically bonded or physically adsorbed to the surface of carbon spheres. The microstructure and properties of the two types of composites were compared. The thermogravimetric analysis data confirmed that the presence of CSs in the polymer\carbon composites is responsible for the higher thermal stability of the composite material in comparison with pristine polythiophene. The FTIR analysis showed that covalent functionalized nanocomposites exhibit a high intensity of a C-S bond This study reports on the synthesis of N-doped carbon spheres (N-CSs) by a simple synthetic procedure. A horizontal CVD type reactor was used to synthesize N-CSs from pyridine. Depending on the dilution of the pyridine with toluene, a nitrogen content of 0.13-5 mol % was obtained. The use of a vertical CVD reactor gave N-CSs with a N-content of 0.19-3 mol % when an ammonium solution and acetylene were used as reactants. The diameters of carbon spheres were found to be in the range of 40 nm to 1000 nm for both CVD reactors. The diameter can be controlled by varying the flow rate, temperature, time, concentration and the reactor type. The samples were characterized by TEM, HRTEM, elemental analysis, Raman spectroscopy, TGA, PXRD and ESR. We have demonstrated that unsubstituted thiophene can be polymerized by Fe3+-catalyzed oxidative polymerization. The average particle size was about 50 nm, within a narrow particlesize distribution. The undoped carbon spheres (CSs) were reacted with thiophene to give polymer/carbon composites containing polythiophene and carbon nanospheres via chemical oxidative polymerization reaction. Polythiophene molecules were either chemically bonded or physically adsorbed to the surface of carbon spheres. The microstructure and properties of the two types of composites were compared. The thermogravimetric analysis data confirmed that the presence of CSs in the polymer\carbon composites is responsible for the higher thermal stability of the composite material in comparison with pristine polythiophene. The FTIR analysis showed that covalent functionalized nanocomposites exhibit a high intensity of a C-S bondThis study reports on the synthesis of N-doped carbon spheres (N-CSs) by a simple synthetic procedure. A horizontal CVD type reactor was used to synthesize N-CSs from pyridine. Depending on the dilution of the pyridine with toluene, a nitrogen content of 0.13-5 mol % was obtained. The use of a vertical CVD reactor gave N-CSs with a N-content of 0.19-3 mol % when an ammonium solution and acetylene were used as reactants. The diameters of carbon spheres were found to be in the range of 40 nm to 1000 nm for both CVD reactors. The diameter can be controlled by varying the flow rate, temperature, time, concentration and the reactor type. The samples were characterized by TEM, HRTEM, elemental analysis, Raman spectroscopy, TGA, PXRD and ESR. We have demonstrated that unsubstituted thiophene can be polymerized by Fe3+-catalyzed oxidative polymerization. The average particle size was about 50 nm, within a narrow particlesize distribution. The undoped carbon spheres (CSs) were reacted with thiophene to give polymer/carbon composites containing polythiophene and carbon nanospheres via chemical oxidative polymerization reaction. Polythiophene molecules were either chemically bonded or physically adsorbed to the surface of carbon spheres. The microstructure and properties of the two types of composites were compared. The thermogravimetric analysis data confirmed that the presence of CSs in the polymer\carbon composites is responsible for the higher thermal stability of the composite material in comparison with pristine polythiophene. The FTIR analysis showed that covalent functionalized nanocomposites exhibit a high intensity of a C-S bond at 695 cm-1 , which is not observed in the noncovalent functionalized nanocomposites