来源：塑料托盘 发布时间：2010年7月29日
塑料托盘以“碳-水”化学为主线,利用C-H-O体系的化学反应探索碳纳米管的软化学合成,剪裁与修饰,以及在化学、化工方面的新性质与应用。在碳纳米管的合成中借助C-H-O体系复杂的化学反应,在常压,无催化剂的条件下,通过水辅助的一步“淬火”法实 塑料托盘现由石墨到高质量多壁碳纳米管的转变。从碳水化合物出发,用“草”作为碳源,通过氧气辅助的多次热解得到多壁碳纳米管。以常见的聚乙二醇(PEG)作为碳源,在低温下(160°C)的水热体系中,没有催化剂的条件下,用氢氧化钠作为辅助试剂来制备多壁碳纳米管。以活性炭作为起始原料,将杂多酸引入180°C水热体系,通过选择不同种类的杂多酸,可以实现碳纳米管、碳纳米带以及碳纳米粒子的可控合成,这一过程中多酸可以多次重复利用。进一步以多酸作为电解质,在有机相中通过电解还原,在阴极得到 塑料托盘单壁碳纳米管、多面体碳纳米晶等多种碳的纳米结构。由合成中得到启示,即水的参与对于形成和纯化碳纳米结构有重要作用。利用多酸的强酸性与氧化性,将钼系杂多酸引入水热过程,实现碳纳米管的剪裁。剪短后的碳纳米管,长度分布范围较窄,没有在管壁中引入新的缺陷。多酸在反应后变为杂多蓝,可通过过氧化氢的氧化逆变回杂多酸,重新利用。同时由水辅助的表面活性剂体系分别在液相和室温固相反应条件下实现多酸盐纳米晶的可控合成,进一步用所得到的多酸盐纳米粒子对碳纳米管进行了修饰。在C-H-O体系中探索性地直接用碳纳米管作为芳烃非均相羟基化反应的催化剂,结果 塑料托盘发现在不需要任何添加剂和溶剂的情况下,用过氧化氢作为氧化剂,可以实现包括苯,甲苯,氯代苯,溴代苯,硝基苯等一系列芳烃的一步羟基化,并且选择性很高(大于98%)。进一步的实验与电化学研究表明,该羟基化反应可能是通过一个环氧乙烯特征的活性氧物种对芳环的进攻完成的。【Abstract】 This thesis focuses on the discussion for synthesis, cutting, and modification for thecarbon nanotubes, which are based on the soft chemistry in the “C-H-O”system.The synthesis and fabrication carbon nanotubes are carried out by soft chemistrymethods in “C-H-O”system. As results, graphite can be transformed into pristine carbonnanotubes with one-step treatment, under the assistance of water, only at atmospheric pressureand without any catalyst. A novel and ‘green' oxygen assisted pyrogenation approach wasdeveloped for the fabrication of carbon nanotubes: from grass to CNTs, using renewablenatural products as the carbon sources and the oxygen, as a benign oxidation reagent. Alow-temperature hydrothermal route has been successfully developed to synthesize CNTs at160℃without catalysts by using PEG as the carbon source. In a polyoxometalates-assistedmild hydrothermal system, active carbon powder can be transformed into carbonnanoparticals, carbon nanotubes, and carbon nanobelts by using different kindpolyoxometalates as catalyst. This is a convenient, controllable, and renewable approach forthe synthesis of carbon nanomaterials with the participation of polyoxometalates. In addition,single-walled carbon nanotubes, cubic carbon nanocrystals, and other carbon nanostructuresalso can be synthesized through a polyoxometalates-assisted soft electrochemical reductionprocess at room temperature.A simple polyoxometalates assisted mild hydrothermal method was developed forcontrolled cutting carbon nanotubes without increasing sidewall damage. After the reaction,the polyoxometalates used were changed into heteropoly blues, which can be converted backto the polyoxometalates with the addition of a small amount of H2O2 solution. Moreover, aseries of novel polyoxometalates nanocrystals have been prepared by a surfactant-assistedsolution-and solid-phase route. We have further directly observed the attachment ofpolyoxometalates nanoparticles to oxidized carbon nanoparticals due to the chemicaladsorption between carboxylic acid groups of carbon nanoparticals and polyoxometalatesnanoparticles.Multi-walled carbon nanotubes are directly used as catalyst for the hydroxylation ofaromatic hydrocarbons. Curved sp2-hybridized carbon surface of carbon nanoparticals playsan important role in the selective catalytic reactions. The active oxygenated species, withstrong oxene characters, may be generated through the interaction between the hydrogenperoxide and the carbon nanoparticals. Without the assistance of any solvent or additive, highselectivity up to 98% was obtained. Carbon nanoparticals were proved to be a high-active,high-selective, and good-reproductive heterogeneous catalyst.