【作者】 王秀英；

【导师】 李吉学；

【作者基本信息】 吉林大学 ， 无机化学， 2009， 博士

【摘要】 碳纳米管具有独特的一维纳米结构、极高的纵横比和良好的导电性,将这些优异性能集于一身使得它的应用领域非常广泛,尤其在复杂环境下制备多功能特种复合材料时更显出其无可比拟的优越性。高性能碳纳米管纳米复合材料的研究已成为碳纳米管的重要应用研究方向之一,具有重要的基础理论研究意义。本文利用碳纳米管和金属氨络合离子反应制备出ZnO、CuO、Cu2O、Cu、CoO、NiO纳米粒子沉积在碳纳米管表面的复合材料,还得到了花状ZnO和Cu2O纳米粒子只连接在碳纳米管端口形成的异质结。对ZnO/MWNT复合材料的光电性质研究发现,ZnO与碳纳米管之间有光生电荷传递作用,且ZnO与碳纳米管之间的接触面积越大越利于其电荷传递的发生。复合材料的瞬态光伏测试结果显示有极性反转,其中正响应为ZnO自身产生光电压的过程,负响应为ZnO与碳纳米管之间电荷传递的过程。对不同粒径Cu2O修饰的碳纳米管进行紫外-可见吸收光谱测试表明具有较小粒径的Cu2O纳米粒子由于量子限域效应会引起吸收谱带一定程度的蓝移。对CoO/MWNT及NiO/MWNT复合物的磁性研究发现,由于CoO及NiO的小粒径使得这两种复合物在室温都表现出超顺磁性。更多还原

【Abstract】 Carbon nanotubes (CNTs) with unique structure and excellent chem-physical properties have attracted increasing interest because novel applications have been found for these materials in catalysis, electrode fabrication and gas storage/separation. Recently, as a new hybrid material, metal or metal oxides/CNT composites have received much attention for their promising applications in gas sensors, supercapacitors and so on. In our work, a series of metal or metal oxides/multi-walled carbon nanotube (MWNT) composites with controlled morphology have been obtained via the interaction of M(NH3)x2+ ions and acid-treated MWNTs. The photoelectric and magnetic properties of the obtained products have been studied.A simple method has been employed to modify MWNTs with ZnO nanostructures by zinc-ammonitum complex ion covalently attached to the MWNTs through the C?N bonds. When acid-treated MWNTs are soaked in the Zn(NH3)42+ solution at room temperature for a short time, the concentration of the Zn(NH3)42+ on the tips of the MWNTs is rather high due to the presence of a large number of carboxyl groups. As a result, the concentration of CONH2?Zn(NH3)32+ groups formed by the reaction of the amide and carboxyl in the intermediate products is high and favors the formation of flower-like structures on the tips of MWNTs after calcination. When prolonging the soaking time, the Zn(NH3)42+ are dispersed homogeneously around the MWNTs, and the concentration of CONH2?Zn(NH3)32+ groups in the intermediate products is low and prefers the formation of nanoparticles around the MWNTs after calnination. Photoluminescence measurements of the obtained products, strongly influenced by the ZnO nanostructures, have been performed. PL peak of ZnO nanoparticles directly attached to MWNTs is quenched to a considerable extent compared with that of flower-like ZnO in the flower-like ZnO/MWNT heterojunctions. It is due to the interaction of ZnO nanoparticles in excited state and MWNTs in electron transfer process. The photovoltage transient results of both of the hybrid materials display a positive response, which attributed to the photovoltage from ZnO attached to MWNTs, and a negative response which due to the transfer of photoinduced electrons of ZnO to MWNTs.CuO/MWNT composites have been prepared by the interaction of Cu(NH3)42+ ions and carboxyl groups on the surface of MWNTs. Cu/MWNT composites have also been prepared by adjusting the calcination temperature. In addition, Cu2O/MWNT composites have been obtained by increasing the amount of NH3?H2O. The morphology of Cu2O/MWNT composites could be controlled by adjusting the soaking time. UV?visible absorption spectra of the obtained Cu2O/MWNT composites present a blue-shift with the decrease of particle size, which could be attributed to the quantum confinement effect.Decoration of the MWNTs with CoO and NiO nanoparticles has been achieved via the interaction of M(NH3)x2+ (M = Co, Ni) ions and carboxyl groups on the surface of MWNTs. Both CoO/MWNT and NiO/MWNT composites present superparamagnetic behavior at 300 K, which can be attributed to the small particle size of CoO and NiO nanoparticles.更多还原