【作者】 章仪；

【导师】 陈文哲；

【作者基本信息】 福州大学 ， 材料学， 2003， 硕士

【摘要】 为了寻找制备碳纳米管及其碳纳米一维材料用的纳米金属催化剂以及解决纳米团聚及分散稳定性的问题，本研究建立了脉冲激光轰击液体流动相中固体靶连续制备纳米金属溶胶的新方法，其特点在于：将流动液相引入激光轰击技术，可实现连续制备；固体靶与流动液相的成分可随意调节，具有广泛的适用性。 运用上述方法，成功制备了铁、钴、镍、金、钛、钨等多种金属乙醇溶胶，所获得的纳米金属颗粒粒径大多介于10～30nm之间。重点选取纳米铁乙醇溶胶和纳米钨乙醇溶胶以及其中的纳米颗粒进行了详细表征，所涉及的测试方法包括X射线衍射、傅立叶红外光谱、紫外-可见光谱、荧光光谱、透射电子显微镜及选区衍射、扫描电子显微镜及微区能谱分析等等。 首次提出了用UV-Vis吸光度变化规律来评估分散剂添加量与分散效果的方法，较系统地研究了纳米金属溶胶添加分散剂后的吸光度(激子峰强度)与分散剂添加浓度的关系以及吸光度随放置时间的变化规律，从而获得了合适的表面活性剂和最佳添加浓度，成功实现了纳米金属溶胶中铁与钨纳米颗粒的分散。UV-Vis法理论分析结果表明，对于纳米铁溶胶，添加0.035％的非离子型表面活性剂十二烷醇聚氧乙烯醚可以达到良好的分散稳定性；而对于纳米钨溶胶，最理想的分散剂则是0.13％的阴离子表面活性剂十二烷基苯磺酸钠，电镜观察结果完全证实了该推论，显示5天后的纳米金属溶胶仍然保持良好的分散状况。该方法的提出对于今后寻找特定纳米颗粒材料的分散剂具有理论指导意义。 在上述研究的基础上，采用铁、钨两种纳米金属作为催化剂，运用化学气相沉积法和激光轰击原位生成法尝试合成碳纳米管与纳米线。结果表明：采用化学气相沉积法时，在使用石英基底的情况下获得了碳纳米一维生成物，其中以纳米钨作为催化剂时获得的一维生成物形态笔直，数量可观；采用激光轰击原位生成法时，尝试了两种工艺，其一是石墨靶浸于先期制备的催化剂流动相，其二是将催化剂原料与石墨混合成固体靶，结果显示后者获得的碳纳米一维生成物数量明显多于后者，并且长度相当可观，有的可达数百微米。其中以钨作为催化剂原料与石墨混合制成固体靶，蒸馏水作为流动相时，得到的纳米纤维状产物直径不到10nm，而且形状笔直，值得关注，目前国内外尚无以钨作为催化剂成功制备纳米一维碳材料的报道，因此该研究具有崭新而广阔的研究前景。更多还原

【Abstract】 A new method for successive preparation of nano-metal sols by pulsed laser ablation at the interface of gas, solid and flow-liquid is developed. This method has two advantages: successive preparation and broad applicability.Nano-metal/ethanol sols, including Fe, Co, Ni, Au, Ti and W, were successfully obtained by this method. The diameters of metal particles in the sols were between 10~30nm. Especially, the nano-iron and nano-tungsten sols as well as their powders were characterized in detail by XRD, FT-IR, UV-Vis, XFS, TEM, SEM, EDAX and so on.Another new method is put forward firstly to estimate the addition of dispersants and its effect by UV-Vis. The relation of absorption of nano-metal sols and the addition of dispersants, as well as the rule of absorption of nano-metal sol added by dispersants concomitant to placing time were systematically investigated by means of UV-Vis. The results show that, the suitable dispersant to nano-iron/ethanol sol is 0.035% polyoxyethylene(10) lauryl ether(OP-10), but in the case of nano-tungsten/ethanol sol, 0.13% neotelex maybe is of more benefit to its disperse stability. The observation of TEM shows the best evidences. This result is instructional to find out effective dispersants for particular nano-particles.Using nano-iron and nano-tungsten as catalyzers, we try to produce carbon nanotube or nanostring by CVD and PLA. The results show that one-dimension carbon nanomaterials can be successfully obtained by CVD only based quartz module. While if pulse laser ablation is applied, the output of mixed target is obviously more than that of plumbago target. The carbon nanotubes prepared by nano-tungsten catalyzer are very straight without any bent and their diameters are under 10nm. It is worth to pay more attention and need to study further .更多还原