碳纳米管及C60和石墨氧化动力学机理函数的分析

The oxidation of carbon nanotubes, C60 and graphite was studied by thermogravimetric (TG) analysis and differential thermal analysis (DTA) technique, and the oxidation kinetic models of three carbon materials studied were analyzed by mechanism-function method. The results indicate that three carbon species adopt different oxidation mechanisms due to their different structures. The oxidation of carbon nanotubes with cylindrical structure follows contracting volume reaction mechanism [R3 mechanism, 1-(1-α)1/3 = kt], indicating that the oxidation of carbon nanotubes takes place from the ends to the center. For graphite with planar sandwich structure, the oxidation starts at the edges initially and gradually moves toward the center, which corresponds to contracting area phase boundary reaction mechanism [R2 mechanism, 1-(1-α)1/2 = kt]. The oxidation of C60 with spherical structure, however, is complex and apparently cannot be illustrated with a single kinetic model. The values of apparent activation energy     

MgO—C耐火材料中石墨相的氧化动力学

树脂结合的ＭｇＯ－Ｃ石墨耐火材料的脱碳是砖衬在使用性能中最重要的参数之一，这一性能在空气环境中于１０００－１４００℃温度下曾运用动力学进行过研究，该作用是以氧燃烧碳作为主要碳化机理。通过气体分析测定随反应时间而的ＣＯ变成ＣＯ２的量，从而得到碳的燃烧率。由氧化动力学推导出使用的一种数学模型已使试验的结果合理化，其中外部大气中的氧向砖内部的扩散率是主要的。     

改进Hummers法制备氧化石墨及其机理分析

在传统的Hummers法制备氧化石墨基础上,先将石墨预氧化,再利用延长中温反应时间来取代传统方法中的高温反应,不仅提高了氧化石墨的产量,使得氧化石墨的氧化程度增加,同时避免了因为高温反应所带来的安全隐患,为制备纯度更高的氧化石墨提供了新的方法和途径。最后对改进的Hummers法制备氧化石墨进行了机理分析。     

改进Hummers法合成氧化石墨及机理探讨

通过延长中温阶段反应时间,对传统Hummers法进行改进,并对所制得氧化石墨烯进行表征及机理分析。结果表明,文章对传统Hummers法的改进,在没有降低石墨的氧化程度的基础上,将反应控制在一个低温、安全稳定的环境下进行,减少了危险,降低了能耗。     

异丁烯催化氧化的动力学及机理的探讨

制取有机玻璃新方法——异丁烯催化氧化法—是1983年在日本建厂投产的。其法的第一步是生产甲基丙烯醛,进一步是生成甲基丙烯酸,虽然钼铋体系催化剂有较好的活性和选择性,但这类催化剂的氧化动力学研究和机理探讨不够彻底。本文在钼铋多元体催化剂上进行异丁烯氧化动力学的研究和机     

蒎烷氧化反应机理及动力学研究

分别推导了单分子退化支化引发和双分子退化支化引发时的动力学模型，并根据实验数据对两种模型进行了分析。结果表明：在蒎烷氧化反应中，认为单分子退化支化引发为主的模型假设是合理的，根据这一机理，建立了相应的动力学模型，并由实验得到了相关的动力学参数。     

C/C复合材料的氧化动力学研究

通过氧化失重分析研究了加压焙烧法制备的短纤维Ｃ／Ｃ复合材料的氧化动力学过程。结果表明：短纤维增强Ｃ／Ｃ复合材料的氧化速率随着温度的升高而升高。     

石墨化过程的热力学和动力学分析

一、前言 为了研究碳素材料石墨化时性能的变化和决定最佳的温度规范,有两个理论问题要加以探讨:一是热力学的,即在一定的外部条件下,物料体系中的热力学平衡状态;二是动力学的,即碳素在热处理过程中石墨化的速度。 这就需要测定碳素材料在不同温度下的热容,它们的燃烧热和一定温度下的氧化速度,作为计算石墨化热力学函数的依据,还要测定材料石墨化前后性能的变化,如电导     

醇催化氧化成羰基化合物的动力学和机理

对在PdⅡ四水配合物和FeⅡ-FeⅢ水合离子存在下,低级脂肪醇C1-4和分子氧化含水介质中,在40-80℃下氧化成对应的羰基化合物进行了研究。将芳基化合物(乙酰苯、苄腈、苯乙腈、邻氰基甲苯、硝基     

氧化石墨及硅烷偶联剂改性氧化石墨填充环氧树脂复合材料性能研究

采用改进Hummers法制得氧化石墨,采用硅烷偶联剂γ-缩水甘油醚氧丙基三甲氧基硅烷(GPTS)进行改性,用TGA、XRD、XPS表征出氧化石墨和改性氧化石墨的形态和性质。通过超声共混制得其复合材料,测试得到其固化性能、导热性能和力学性能。结果表明:制备的氧化石墨对环氧树脂固化有促进作用,改性氧化石墨对环氧树脂固化并无明显影响。硅烷偶联剂改性氧化石墨作为分散相得到的复合材料的导热性能、弯曲强度和拉伸断裂强度相对于氧化石墨填充复合材料有所提高。     

碳纳米管的提纯──重铬酸钾氧化法

利用重铬酸钾氧化法对纳米管进行了提纯。考察了温度、硫酸浓度、时间等因素对反应的影响,得到了最佳工艺条件。     

High Methanol Oxidation Activity of Well-Dispersed Pt Nanoparticles on Carbon Nanotubes Using Nitrogen Doping

Pt nanoparticles (NPs) with the average size of 3.14 nm well dispersed on N-doped carbon nanotubes (CNTs) without any pretreatment have been demonstrated. Structural properties show the characteristic N bonding within CNTs, which provide the good support for uniform distribution of Pt NPs. In electrochemical characteristics, N-doped CNTs covered with Pt NPs show superior current density due to the fact that the so-called N incorporation could give rise to the formation of preferential sites within CNTs accompanied by the low interfacial energy for immobilizing Pt NPs. Therefore, the substantially enhanced methanol oxidation activity performed by N-incorporation technique is highly promising in energy-generation applications.     

炭载Pt基催化剂上甘油氧化反应路径的探究

结合透射电镜(TEM)和X射线光电子能谱(XPS)等表征技术,比较研究了碳纳米管(CNTs)负载的单金属Pt和双金属Pt-Sb催化剂的结构及其非碱性条件下催化甘油氧化反应的性能与路径。结果表明:Sb的引入对催化剂的粒径以及Pt电子性质的影响较小,但Sb可能选择性沉积在Pt原子表面形成空间位阻,控制甘油的转化向有利于其仲羟基氧化的方向进行,从而改变了反应的选择性和路径。Pt/CNTs催化剂主要选择性氧化甘油的伯羟基生成甘油醛(GLyD)和甘油酸(GLYA),GLYA再进一步氧化生成羟基丙酮酸(HPYA)和亚酒石酸(TA);Pt-Sb/CNTs催化剂则优先氧化甘油的仲羟基生成二羟基丙酮(DHA),DHA进一步氧化生成HPYA;两种反应路径下生成的HPYA和TA最终都会氧化断键生成乙醇酸(GLYCA)等产物。     

纳米碳管对CL-20热分解性能的影响

用DSC和TG研究了含纳米碳管的CL-20热分解特性。结果表明,纳米碳管的加入降低了CL-20的起始分解温度和分解峰温度,活化能由原来的184．3kJ／mol降低为172．2kJ／mol,放热量也由原来的2604．48J／g降低到2256．69J／g。同时,随着纳米碳管百分含量的增大,CL-20的起始分解温度、分解峰处温度、活化能以及放热量都逐步降低。     

Synthesis Mechanisms,Structural Models,and Photothermal Therapy Applications of Top-Down Carbon Dots from Carbon Powder,Graphite, Graphene,and Carbon Nanotubes

In this study, top-down syntheses of carbon dots (CDs) from four different carbon precursors, namely, carbon nano powders, graphite, graphene, and carbon nanotubes, were carried out. Systematic study demonstrated that the optical properties and surface functionalities of the CDs were quite similar and mainly influenced by the synthesis method, while the sizes, morphologies, chemical compositions, and core structures of the CDs were heavily influenced by the carbon precursors. On the basis of these studies, the formation processes and structural models of these four top-down CDs were proposed. The cell cytotoxicity and photothermal conversion efficiency of these CDs were also carefully evaluated, demonstrating their potential applications in photothermal therapy.     

碳纳米管的制备

作为纳米材料典型代表之一的碳纳米管自被发现以来 ,以其独特的结构和性能引起了人们广泛的关注 ,本文简介了碳纳米管的发展和现状 ,详细阐述了碳纳米管的几种制备方法。     

Kinetic and Thermodynamic Studies of the Adsorption of Several Anionic Dyes From Water Samples on Magnetite-Modified Multi-Walled Carbon Nanotubes

In this study magnetite-modified multi-walled carbon nanotubes (MMMCNTs) were used as an adsorbent for the removal of four anionic dyes from aqueous solutions. Batch studies were performed to address various experimental parameters for the removal of these dyes. Kinetic studies showed that the adsorption of dyes on MMMCNTs was almost a rapid process. Quasi equilibrium was reached in 45 min. Pseudo-first-order and pseudo-second-order models were applied to fit the experimental data and the results show that the adsorption of dyes followed the pseudo-second-order kinetic model. The thermodynamic analysis indicates an increase in the temperature resulted in increasing the dyes adsorption capacity of the adsorbent indicating the process to be endothermic.     

碳纳米管的制备

综述了碳纳米管的几种制备工艺和相关的生长机制,还介绍了近两年来碳纳米管制备的进展情况,包括新型制备技术、特殊结构的碳纳米管制备。     

碳纳米管制备的研究现状

碳纳米管越来越受到科学界和企业界的关注，这主要是因为它具有奇特的物理，化学性质和很好的应用前景。本文对碳纳米管的结构，性质以及应用进行了简单的介绍，同时介绍了碳纳米管的一些表征方法，并对碳纳米管制备的研究现状做了较详细的综述。