功能化富勒烯的自组装及其在燃料电池中的应用

发布时间：2018-06-06 14:40

本文选题：富勒烯 + 自组装　；参考：《东华大学》2014年硕士论文

【摘要】：自富勒烯(C60)被发现近30年来,由于其独特的分子结构赋予其材料优良的光电性能,持续得到了大量关注。另一方面,燃料电池曾被美国时代杂志评为21世纪对人类最有影响的十大高新技术之一近年来合成价格低廉且性能优越的燃料电池催化剂亦为重要的热点课题之一。富勒烯具有良好的自组装能力,可以通过调控其自组装得到大比表面积的复杂结构形貌；由于催化剂的比表面积与其催化活性密切相关,具有大比表面积富勒烯自组装结构在催化剂载体应用方面应具有潜在价值,但这方面的研究报道甚少。因此本论文主要从以下两个方面开展了工作：合成功能化富勒烯衍生物并调控其自组装以及探索富勒烯自组装结构在燃料电池催化剂材料中的应用。首先本论文设计合成了含有羧基、酯基和硝基等功能基团的富勒烯衍生物(富勒烯本身比重高于75%),并系统研究了这些衍生物在不同实验条件下(如溶剂、基质、氛围和温度等)的自组装规律。结果表明：溶剂的性质、功能基团的位置等在一定程度影响其自组装后的形貌；基质并不是影响自组装形貌的主要因素。对于所合成的功能化富勒烯衍生物,均可通过条件优化来调控其自组装行为,得到比表面积较大的复杂花球形貌结构。通过XRD研究发现,这些复杂花球形貌结构中富勒烯通过π-π(C60/C60)堆积作用以之字形错位方式自组装排列。同时,本文还对功能化富勒烯衍生物的电化学性质和光谱性质进行了研究；并通过理论计算研究了取代基位置与分子轨道能级之间的关系,在3种硝基苯基取代的富勒烯衍生物中,发现邻位硝基的氧原子上的孤对电子与富勒烯笼π电子之间存在轨道相互作用力,可显著提高其LUMO能级。其次,将富勒烯衍生物自组装结构作为催化剂载体,探索了其在燃料电池中的应用。将Pt或Pd利用电化学还原沉积在富勒烯自组装结构覆盖的ITO电极上制得复合催化剂,通过催化甲醇氧化对其电催化性能进行了评价,初步结果表明富勒烯自组装结构的引入可使催化剂的催化活性显著提高。同时,用硼氢化钠还原法制备了一类性能优越的负载在羧基化多壁碳纳米管上的空心型核壳结构M@Pt-CNTs或M@Pd-CNTs新型催化剂(M为Co、Ni或CoNi合金)。
[Abstract]:Since the discovery of fullerene (C60) in recent 30 years, it has been paid more and more attention due to its unique molecular structure and its excellent optoelectronic properties. On the other hand, fuel cell has been regarded as one of the ten most influential high and new technologies in the 21st century by American time magazine. In recent years, low cost and superior performance fuel cell catalyst is also one of the important hot topics. Fullerene has good self-assembly ability and can obtain complex structure morphology of large specific surface area by regulating its self-assembly, because the specific surface area of the catalyst is closely related to its catalytic activity. Fullerene self-assembly structure with large specific surface area should have potential value in the application of catalyst carrier, but there are few reports in this field. Therefore, in this thesis, the following two aspects of work have been carried out: synthesis of functionalized fullerene derivatives and regulation of their self-assembly, and exploration of the application of fullerene self-assembly structure in fuel cell catalyst materials. In this paper, fullerene derivatives with carboxyl, ester and nitro groups were designed and synthesized (the specific gravity of fullerene is higher than 75%), and the effects of different experimental conditions (such as solvent, substrate, etc.) on these derivatives were systematically studied. The self-assembly law of atmosphere and temperature etc. The results show that the properties of the solvent and the position of the functional groups affect the morphology of the self-assembly to a certain extent, and the matrix is not the main factor affecting the morphology of the self-assembly. For the functionalized fullerene derivatives, the self-assembly behavior can be controlled by optimizing the conditions, and the morphology and structure of the complex floral spheres with large specific surface area can be obtained. It was found by XRD that fullerene was self-assembled by 蟺-蟺 C60 / C60 stacking in these complex orbicular structures in the form of zigzag dislocation. At the same time, the electrochemical and spectral properties of the functionalized fullerene derivatives are studied, and the relationship between the substituent positions and the molecular orbital energy levels is studied by theoretical calculation. Among the three kinds of nitrophenyl substituted fullerene derivatives, it is found that there exists orbital interaction between the lone pair electrons in the oxygen atom in the o-nitro-position and the 蟺 electrons in the fullerene cage, which can significantly improve the LUMO energy level of the fullerenes. Secondly, the self-assembly structure of fullerene derivatives was used as catalyst carrier to explore its application in fuel cells. A composite catalyst was prepared by electrochemical reduction deposition of Pt or PD on a fullerene self-assembled ITO electrode. The electrocatalytic performance of Pt or PD was evaluated by methanol oxidation. The preliminary results show that the addition of fullerene self-assembly structure can significantly improve the catalytic activity of the catalyst. At the same time, a class of hollow core-shell structure M@Pt-CNTs or M@Pd-CNTs catalysts with excellent properties supported on carboxylated multiwalled carbon nanotubes were prepared by sodium borohydride reduction method.
【学位授予单位】：东华大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：O613.71;TM911.4

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