Synthesis And Application Of Carbon Nanotubes Supported Catalysts

With unique nano-structures, peculiar electrical capability, fine flexibility, good chemical and thermal stability and adsorption property, carbon nanotubes(CNTs) are widely used in the fields of composites, hydrogen-storage and field emission, etc. Their application in catalysis is one of the hot fields in recent studying of carbon materials. The goal of the thesis is to explore carbon nanotubes as a carrier, through the load of metal nanoparticles and chiral groups by different methods, to catalyze respectively Suzuki cross-coupling reaction and asymmetric aldol condensation reaction, and then to study the reaction conditions and discuss the relationship between the structure and catalytic properties of the composites. It lays the foundation to expand functional carbon nanotubes based hybrid materials in the application of catalytic. The main work of this thesis includes:1. Using chemical reduction of Cu, Ni, Pd nanoparticles with carbon nanotubes, we prepared some hybrid materials, which were characterized by X-ray powder diffraction and transmission electron microscopy, then catalyzed Suzuki cross-coupling reaction. Pd/carbon nanotubes hybrid materials displayed better catalytic properties.2. Carbon nanotubes were chemically modified by four different methods, i.e., carboxylation, carboxylation and supported Ni, amination, grafting polyamide-amine (PAMAM) dendrimer, then supported with Pd nanoparticles. The products were characterized by X-ray powder diffraction, infrared spectroscopy, transmission electron microscopy, thermal gravimetric analysis, atomic absorption spectrometry and then catalyzed Suzuki cross-coupling reaction. The results showed both aminated carbon nanotubes and carbon nanotubes grafted with polyamide-amine dendrimer loaded with Pd nanoparticles gave better catalytic effect. The catalytic effect of Pd/CNTs -PAMAM hybrid material was similar to Pd nanoparticles stabilized by PAMAM, Polyvinyl Pyrrolidone, Polyethylene Glycol. And it was not the use of ligand, and the amount of Pd was only 0.28 mol %. In addition, the catalyst has good thermal stability, can be easily kept and recovered. Recycled six times it remained high activity.3. Carbon nanotubes were chemically modified in three different ways, i.e., carboxylation, amidation, grafting polyamide-amine dendrimer, and then L-proline was grafted on it. These products were characterized by infrared spectroscopy, thermal gravimetric analysis, and the results showed L-proline was grafted on them all. The study accumulated experiences to the carbon nanotubes based chiral materials preparation and study.