碳纳米管腔内填充二茂铁复合物的制备与理论研究

发布时间：2018-06-25 13:46

本文选题：碳纳米管 + 二茂铁　；参考：《哈尔滨理工大学》2015年硕士论文

【摘要】：随着对碳纳米管研究的深入，填充型碳纳米管吸引越来越多科研人员的关注。一维的腔结构是碳纳米管的重要特点，在碳纳米管纳米级的限域作用下，填充物将表现出特殊的性质。二茂铁是最具有代表性的金属有机物分子，，碳纳米管和二茂铁的碳都是sp2杂化，且都具有遍布整个分子的共轭π电子云，都具有芳香性，将二茂铁填充进入碳纳米管管腔中，二者通过强的π-π相互作用而相互结合，形成特殊的二茂铁填充碳纳米管纳米豆荚结构，具有极高的研究价值。本论文主要分为理论计算和实验合成两部分，二茂铁和二茂钒都是过渡金属茂基化合物，与Fe原子不同，V原子的d轨道存在单电子，自旋向上和自旋向下状态差别很大，因此分别对二茂铁、二茂钒填充碳纳米管复合结构（即：Fe(Cp)2@CNTs，V(Cp)2@CNTs）进行理论计算。基于密度泛函理论（DFT）和非平衡格林函数方法（NEGF）理论，利用ATK软件设计不同填充状态下的Fe(Cp)2@SWNT、 Fe(Cp)2@DWNT、 V(Cp)2@SWNT、V(Cp)2@DWNT复合物的结构模型，计算优化后各结构的总能量、能带结构、态密度、分子能谱及本征态，得出各结构中存在填充物分子到碳纳米管管壁的电子跃迁，填充物分子存在陷阱态效果。在理论计算的基础上，实验合成Fe(Cp)2@CNTs复合物，首先利用体积比为1:3的浓硝酸和浓硫酸的混酸溶液对碳纳米管进行酸氧化改性，再将碳纳米管在氮气气氛下进行退火处理。酸氧化改性后的碳纳米管，长度更短、开口更多，有利于后续的填充实验。填充过程分别利用毛细填充法和气相沉淀法对碳纳米管进行填充，毛细填充法虽然实验条件简单，但填充率较气相沉淀法低，通常其填充率不足气相沉淀法填充率的一半。利用四探针测试仪对复合物导电性进行分析，发现导电性减弱，与理论计算所得结果相符，除此之外，采用扫描电子显微镜(SEM)和透射电子显微镜（TEM）对复合物进行形貌结构分析；采用X射线光电子光谱(XPS)对复合物成分进行分析。
[Abstract]:With the development of carbon nanotubes (CNTs), filled CNTs have attracted more and more attention. One-dimensional cavity structure is an important feature of carbon nanotubes (CNTs). Ferrocene is the most representative metal organic molecule. The carbon of carbon nanotubes and ferrocene are both sp2 hybrids, and they all have conjugated 蟺 electron clouds all over the molecule, which are aromatic, so ferrocene is filled into the cavity of carbon nanotubes. Through the strong 蟺-蟺 interaction, the two formed a special ferrocene filled carbon nanotube (CNT) pod structure, which is of great research value. This thesis is mainly divided into two parts: theoretical calculation and experimental synthesis. Both ferrocene and vanadium are transition metallocene compounds. There is a single electron in the d orbital of V atom different from that of Fe atom, and the spin upward and downward states are very different. Therefore, the carbon nanotubes (CNTsV) filled with ferrocene and diocene (Cp) were calculated respectively by using the new method, which is: (1) Fe (CP) 2future CNTsV (CP) 2R (CNTs). Based on density functional theory (DFT) and non-equilibrium Green's function method (NEGF), the structural models of Fe (CP) _ 2W _ (NT), Fe (CP) _ 2r _ (DWNTT), V (CP) _ 2R _ W _ (NTV) (CP) _ 2R _ (DWNT) complexes were designed by using ATK software to calculate the total energy, energy band structure, density of states of each structure. The molecular energy spectrum and intrinsic states show that there is an electronic transition between the fillers and the wall of CNTs and the effect of trap states on the fillers. On the basis of theoretical calculation, Fe (CP) _ 2 @ CNTs were synthesized experimentally. Firstly, the carbon nanotubes were modified by acid oxidation in a mixture of concentrated nitric acid and concentrated sulfuric acid with a volume ratio of 1:3, and then annealed in nitrogen atmosphere. The carbon nanotubes modified by acid oxidation have shorter length and more openings, which is beneficial to the subsequent filling experiments. Capillary filling method and vapor precipitation method were used to fill carbon nanotubes respectively. Although the experimental conditions were simple, the filling rate of capillary filling method was lower than that of gas phase precipitation method, and the filling rate of capillary filling method was less than half of that of gas phase precipitation method. The electrical conductivity of the composites was analyzed by a four-probe tester, and it was found that the conductivity was weakened, which was consistent with the theoretical results. In addition, scanning electron microscopy (SEM) and transmission electron microscope (TEM) were used to analyze the morphology and structure of the composites. X-ray photoelectron spectroscopy (XPS) was used to analyze the composition of the complex.
【学位授予单位】：哈尔滨理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1;O613.71

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