【作者】 王晓峰；

【导师】 张其清； 翁建；

【作者基本信息】 厦门大学 ， 无机化学， 2007， 博士

【摘要】 近年来,碳纳米材料的合成、性质与应用研究倍受关注。但由于碳纳米材料表面具有疏水性,不适合在水溶液体系中使用。为了扩展碳纳米材料的应用范围,必须对碳纳米材料的表面进行修饰和改性。目前,对碳纳米材料的表面进行修饰和改性主要采用共价修饰和非共价修饰两种方法。一般对碳纳米材料表面修饰和改性都是在材料合成之后进行,但这种改性方法往往会造成碳纳米材料结构的破坏,从而影响碳纳米材料的性能。如何在材料合成的过程中同步完成对碳纳米材料的表面修饰和改性是改善碳纳米材料性质和拓宽其应用领域的重要方向。本文尝试用十氯代芘、八氯苊烯、六氯代苯和六溴代苯作为碳源反应物,在溶剂热条件下发生脱氯反应,在不同反应条件下分别制备了表面氨基修饰的核-壳结构碳包覆纳米颗粒、碳微米管和空心碳球。采用TEM、HRTEM、SEM、XRD、XPS、EDS和UV-vis等分析方法对所制备的各种碳材料的形貌、尺寸、结构以及性质等进行了表征,并初步探索了碳纳米材料的形成机理,进行了相关应用研究。主要研究结果如下:1.溶剂热法一步制备了表面氨基修饰的核-壳结构碳包覆氧化铁纳米颗粒。反应以三价铁和十氯代芘为原料,氨水为氨基来源,通过调控反应温度、时间、溶剂和原料配比等参数优化了反应条件,得到了表面氨基修饰的核-壳结构产物。表征了产物的尺寸、组成和结构,确定了该产物为碳包覆的氧化铁纳米颗粒;对碳壳层的结构和表面组成进行了研究,确定了碳壳层表面具有氨基修饰基团并探讨了产物的形成机理。通过表面氨基与修饰分子中羧基的偶联反应提高了该产物的亲水性。2.以制备碳包覆氧化铁纳米颗粒的反应条件为基础,考察了影响氯代碳化合物脱氯反应的因素,包括反应时间、温度、溶剂和催化剂的影响。研究结果证明,提高反应温度可以提高脱氯效率;改变反应溶剂和催化剂可以在一定范围内改变反应体系的脱氯效率和产物的形念。尝试了用甲酸和甲酸铵代替氨水的反应体系,研究发现,该两种反应体系也可以产生催化脱氯反应,但不能得到表面羧基修饰的碳壳层。比较了几种氯代芳烃的脱氯反应活性,为反应碳源的选择提供了依据。3.溶剂热法一步制备了表面氨基修饰的碳微米管,发现管的内部填充了四氧化三铁。反应以二茂铁和六溴代苯为原料,氨水为氨基来源。系统考察了反应条件对产物形态的影响,研究结果证明,延长反应时间、提高反应温度有利于碳微管的形成;调控反应溶剂可以得到不同形态的碳纳米材料;改变氨水的用量可以得到粗糙或光滑表面的碳微管。表征了产物的组成和结构,确定了产物为填充了四氧化三铁的碳微米管;对碳管的结构和表面组成进行了研究,确定了碳管表面具有氨基修饰的基团并探讨了产物的形成机理,研究结果发现,产物的表面氨基可以还原氯金酸,得到负载金纳米颗粒的碳微管。4.溶剂热法一步制备了表面氨基修饰的空心碳球。反应以二茂铁和六溴代苯为原料,硫脲为氨基来源。探讨了反应条件对产物形态的影响,研究结果证明,延长反应时间、提高反应温度有利于得到空心的碳球:调控反应溶剂的用量可以得到不同尺寸的空心碳球和其他形态的产物;反应体系中加入氨水不利于得到空心碳球,以尿素或硫化钠代替硫脲反应也不能得到空心碳球。用二茂铁与硫脲反应可以得到表面没有氨基修饰的空心碳球。推测形成的空心碳球可能是以硫脲作为模板产物。该空心碳球表面的氨基可以还原氯金酸得到金纳米颗粒。5.研究了碳包覆三氧化二铁纳米颗粒作为磁共振成像造影剂的可行性。研究发现,碳包覆三氧化二铁纳米颗粒可以显著改变溶液的磁共振响应信号强度;不同粒径的碳包覆三氧化二铁纳米颗粒具有不同的造影效果。通过进一步表面改性,如氨基-羧基缩和反应引入叶酸和聚乙二醇基团可以提高纳米颗粒的造影效果。6.研究了实心碳微管和空心碳微管的电化学活性,比较了二者对多巴胺和抗坏血酸的氧化-还原行为的影响。研究发现,在空心碳微管修饰的电极上,由于多巴胺和抗坏血酸的氧化峰位置相差220毫伏,所以能够在抗坏血酸存在的情况下选择性检测多巴胺且最低检测限可达到1.0μM,检测的线性范围在5.0μM到0.1 mM.之间。更多还原

【Abstract】 The application of carbon materials has been slowed due to their insolubility and incompatibility,which can be improved through surface modification. Functional-group-mediated covalent-modification has been utilized in CNTs.The use of covalent chemistry to link DNA to CNTs is also expected to provide excellent stability,accessibility,and selectivity compared with noncovalent bonding.In general, the surface modification of carbon nanomaterials was all post-treatment after functionalizing the surfaces with acid sites,such as refluxed with nitric acid or treated byγ-irradiation.These acid sites are composed of carboxylic groups or hydroxyl groups.However,the intrinsic electrical and mechanical properties of the carbon nanomaterials would be affected by these harsh treatments due to the many damages on carbon nanomaterials.Strategies of functionalization carbon nanomaterials through their synthesis process might overcome this problem.Higher reaction temperature takes advantages in graphitization of carbon nanomaterials,however,generally that is a disadvantage to introduce functional groups through the synthesis process.Relative lower reaction temperature and suitable reaction precurors are important to obtain functionalized carbon materials in one-step process.The main goal of the present work is to develop a simple and effective solvothermal method to synthesize amino-modified carbon nanomaterials,such as core-shell sructure nanoparticles,carbon microtubes and hollow carbon nanospheres. Their morphology,size,structure and properties were characterized systemically by TEM,HRTEM,SEM,XRD,XPS,EDS and UV-vis spectroscopy.The growth mechanism of the carbon nanomaterials with different shapes was discussed.The major results of the thesis are outlined as follows:1.Core-shell structure Fe₂O₃@C nanoparticles with amino groups modified were synthesized in one-pot process by solvothermal method.Exiperiments were performed to optimize the reaction conditions.Further linking with hydrophilic molecules by well-established carboxyl-coupling chemistries will enhance the hydrophilicity and extend the potential application of these core-shell structure nanoparticles.2.Dechlorination effect of solvothermal process to prepare Fe203@C nanoparticles in various reaction conditions,such as reaction time,temperature,solvents and catalysts,was investigated.3.Magnetite encapsulated carbon microtubes with amino groups modified were synthesized in one-pot process by solvothermal method.The effect of reaction condition on the morphology of the products was investigated.4.Hollow carbon nanospheres with amino groups modified were synthesized in one-pot process by solvothermal method.The effect of reaction condition on the morphology of the products was investigated.5.The feasibility of the core-shell structure Fe₂O₃@C nanoparticles used as MRI contrast agents was investigated.6.The electrochemistry properties of the amino-modified carbon microtubes were also investigated.Dopamine can be selectively detected in the presence of ascorbic acid.The minimal detection limit of dopamine is 1.0μM and the linear range of detection is 5.0μM-0.1 mM.更多还原