【作者】 郭佳；

【导师】 郭学锋；

【作者基本信息】 南京大学 ， 化学工程（专业学位）， 2020， 硕士

【摘要】 纳米管材料因其独特的一维管状结构、优异的物理化学性能以及广泛的应用前景,是目前化学、材料科学、微电子等诸多研究领域的热点。其中氧化物纳米管因为种类丰富、组成可调变,具有十分重要的工业应用价值,近年来备受关注。迄今为止,尽管已经有很多关于氧化物纳米管制备的报道,但存在的问题主要是制备方法通用性较差,一般只适用于实验室规模合成,难以进行大批量生产,影响了其实际工业应用。本文致力于发展大批量制备氧化物纳米管的方法及其实际应用探索,主要发展了球磨插层、水热转化和离子交换等方法大批量制备高岭土纳米管、Mg（OH）₂纳米管和Ni（OH）₂纳米管,并通过多种手段对样品进行了分析表征,对高岭土纳米管和Ni（OH）₂纳米管的催化及储能应用进行了初步探索,主要工作内容总结如下:（1）高岭土纳米管的湿法球磨批量制备及其催化应用:发展了一种高效的插层和接枝方法——湿法球磨,以普通片状高岭土（MM高岭土）为原料成功制备出高岭土纳米管,该方法简单高效,适宜于大规模批量生产。经过对时间、浓度等合成条件的优化,发现在优化制备参数条件下,MM高岭土经路线NJU-3制备出的纳米管产率最高,可以有效促使其中大部分高岭土纳米片转变为纳米管,使原料中纳米管的比例从基本没有提升到70-80%,纳米管外径为20-50 nm,内径为10-40 nm,长度在几百纳米到几微米之间,孔容为0.44 cm³/g,比表面积可达96 m²/g。高岭土纳米管经600°C焙烧后仍保持纳米管结构,具有良好的热稳定性。研究发现高能球磨主要加速了插层与接枝过程,显著提升了插层率,大大缩短了反应时间,在此基础上提出了湿法球磨促使片状高岭土卷曲形成高岭土纳米管的合成机理。最后对MM高岭土和制备的高岭土纳米管在催化裂化大港轻柴油反应中的微反活性进行了对比研究,结果表明高岭土纳米管的催化裂化活性比原土提高27.9%,显示出高岭土纳米管很好的工业应用前景。（2）Mg（OH）₂纳米管的水热合成及表征:发展了一种从普通Mg O粉体碱液水热直接制备Mg（OH）₂纳米管的方法。从普通的Mg O粉体出发,通过200°C 48 h的碱液水热条件直接制备出Mg（OH）₂纳米管。该方法原料价低易得,制备过程简单、成本较低,适合大规模制备。制得的Mg（OH）₂纳米管外径为20-60 nm,内径为6-10 nm,长度约为几百纳米到1μm,孔容为0.13 cm³/g,比表面积为25 m²/g。可大批量制备的Mg（OH）₂纳米管在催化、吸附、阻燃等领域具有很好的应用前景。（3）Ni（OH）₂纳米管的离子交换法制备及其超级电容器性能:发展了以Mg（OH）₂纳米管为原料,通过离子交换合成Ni（OH）₂纳米管的制备路线。通过Mg（OH）₂纳米管与Ni²⁺在室温条件下进行离子交换,获得Ni（OH）₂纳米管或Ni（OH）₂复合纳米管,方法简单、高效,可大规模制备。产物的形貌及尺寸结构等表征发现Ni（OH）₂纳米管管径分布和大小与Mg（OH）₂纳米管原料相近。最后对其超级电容器性能进行初步研究,以Ni（OH）₂计的比电容为2197 F·g^-1,显示出较好的超级电容器应用潜力。更多还原

【Abstract】 Owing to the unique one-dimensional tubular structure,excellent physical and chemical properties and wide application prospects,nanotube materials are the focus of many research fields,such as chemistry,material science,microelectronics and so on.Among them,oxide nanotubes are of great industrial application values because of their rich variety and adjustable composition,which have attracted much attention in recent years.So far,although there have been many reports on the preparation of oxide nanotubes,the main problem is that the preparation methods are less versatile.In most cases,the synthetic methods are only suitable for laboratory-scale synthesis and could not provide large quantities,hindering the practical application for industry.This paper is devoted to the development of large-scale preparation methods and practical application of oxide nanotubes.The kaolin nanotubes,Mg（OH）₂ nanotubes and Ni（OH）₂ nanotubes were prepared in large quantities by ball-milling intercalation,hydrothermal process and ion exchange.Besides,the properties of samples were further analyzed and characterized.The catalytic and energy storage applications of kaolin nanotubes and Ni（OH）₂ nanotubes were preliminarily explored.The main research contents and conclusions of the thesis are summarized as follows:（1）Synthesis of kaolin nanotubes by wet ball milling in large quantities and their catalytic application:A high efficient method of intercalation and grafting—wet ball-milling method,has been developed.Kaolin nanotubes with high yield have been successfully prepared from ordinary lamellar kaolin（MM kaolin）.This method was simple and efficient,and was suitable for large-scale synthesis.According to the optimization of the synthesis conditions such as time and concentration,it was found that under the optimized preparation parameters,the yield of nanotubes prepared by MM kaolin via route NJU-3 was the highest,which can effectively promote the conversion of most of the kaolin nanosheets into nanotubes.The proportion of nanotubes was 70-80%.The outer diameter of the nanotubes was 20-50 nm,the inner diameter was 10-40 nm,the length was from a few hundred nanometers to a few micrometers.The pore volume was 0.44 cm³/g,the specific surface area could reach to 96 m²/g.Besides,the nanotube morphology of kaolin nanotubes could be maintained after calcination at600°C,indicating their good thermal stabilty.In addition,it was found that the high-energy ball milling accelerated the intercalation and grafting processes,which significantly improved the intercalation rate and greatly shortened the reaction time.On the basis of the study,a synthesis mechanism of wet ball milling to promote the formation of kaolin nanotubes by curling the lamellar kaolin was proposed.Finally,the micro-reactivity of MM kaolin and nanotubes in the fluidized-bed catalytic cracking of Dagang Light Diesel was tested.The results showed that the activity of kaolin nanotubes was about 27.9%higher than that of the MM kaolin,indicating the good prospect of industrial application of the kaolin nanotubes.（2）Hydrothermal synthesis and characterization of Mg（OH）₂ nanotubes:A method for preparation of Mg（OH）₂ nanotubes direct from ordinary Mg O powder has been developed.The Mg（OH）₂ nanotubes were successfully prepared by alkali hydrothermal method at 200°C for 48 h from the ordinary irregular Mg O powder.The raw material was cheap and easy to obtain.Besides,the preparation process was simple,low cost,and suitable for large-scale preparation.The outer diameter of the prepared Mg（OH）₂ nanotubes was 20-60 nm,and the inner diameter was about 6-10 nm.Besides,the length of Mg（OH）₂ nanotubes was about several hundred nanometers to 1μm,and the pore volume was 0.13 cm³/g,while the specific surface area was 25 m²/g.The Mg（OH）₂ nanotubes,which could be prepared in large quantities,has good application prospects in the fields of catalysis,adsorption,and flame retardancy.（3）Synthesis of Ni（OH）₂ nanotubes by ion exchange and their supercapacitor performance:A route for the synthesis of Ni（OH）₂ nanotubes by ion exchange using Mg（OH）₂nanotubes as raw materials was developed.The Ni（OH）₂ nanotubes or hybrid Ni（OH）₂ nanotubes were obtained by ion exchange between Mg（OH）₂ nanotubes and Ni²⁺at room temperature.The method was simple,efficient and could synthesize Ni（OH）₂ nanotubes in a large scale.The characterization on the morphology,size and structure of the Ni（OH）₂ nanotubes showed that the diameter distribution and size were similar to those of the pristine Mg（OH）₂ nanotubes.Finally,the supercapacitor performance of Ni（OH）₂ nanotubes was primary explored.The specific capacitance was 2197 F·g^-1 calculated based on Ni（OH）₂,indicating the excellent potential supercapacitor application.更多还原