Statistical properties of carbon nanostructures

We look at modeling carbon nanostructures from a theoretical graph network view, where a graph has atoms at a vertex and links represent bonds. In this way, we can calculate standard statistical mechanics functions (entropy, enthalpy, and free energy) and matrix indices (Wiener index) of finite structures, such as fullerenes and carbon nanotubes. The Euclidean Wiener index (topographical index) is compared with its topological (standard) counterpart. For many of these parameters, the data have power law behavior, especially when plotted versus the number of bonds or the number of atoms. The number of bonds in a carbon nanotube is linear with the length of the nanotube, thus enabling us to calculate the heat of formation of capped (5,5) and (10,10) nanotubes. These properties are determined from atomic coordinates using MATLAB routines.     

激光光谱电化学

本文对激光光谱电化学的基本问题及研究现状进行了评述，简述了其历史的发展过程，按实验方法将其进行分类并阐述了相应的特点和装置，较系统地介绍了其在理论方面研究和电化学中应用，展望了发展方向，共引用４１篇文献。     

Spectroelectrochemistry of Carbon Nanotubes

This Minireview is a critical survey of results accumulated during the last decade on the characterization of carbon nanotubes using a combination of electrochemical and spectroscopic methods. The article updates earlier reviews on the topic with special emphasis to recent progress in the field.     

Spectroelectrochemistry of tetracyanoquinodimethane modified electrodes

Thin films of a tetracyanoquinodimethane (TCNQ) oligomer adsorbed on optically transparent platinum electrodes have been studied using spectroelectrochemical techniques. In contact with aqueous electrolytes the electron aceptor sites in these modified electrodes are reduced to mixtures of the radical aion, TCNQ^?, the dimer radical anion, TCNQ^2?₂, the dimer dianion, TCNQ₂^2?, and the dianion, TCNQ^2∮. Electrolyte effects on the reduction process and the stability of the reduced films were studied. Both monovalent and divalent ions exhibited Nernstian potential dependence, and in the presence of Ca²⁺ ions the dianion state was stabilized. Counterion effects are suggested as the origin of variations in the wave shape in multcycle voltammograms.     

Oxygen adsorption by fullerenes and carbon nanostructures

The dependences of oxygen sorption on time, gas pressure (up to 760 torr), and sample temperature were determined experimentally for three adsorbents (fullerene, astralene, and activated carbon). The difference in their adsorption abilities was shown to be related to the special features of their structures, primarily to the differences in surface area and pore volume. This conclusion was substantiated by X-ray studies of the structure of the powders. The characteristic heats of adsorption, specific surface areas, pore volumes and sizes, and characteristic energies of adsorption, which are responsible for the sorption properties of the adsorbents studied, were determined.     

Construction of various nanostructures on carbon nanotube films

Construction of nanostructures on surfaces has appealed intensive attention due to its significant applications in diverse fields. Especially, engineering surface properties via surficial nanostructures is actually the creation of functional interface-based materials and slated to be the key aspect for the future of materials science. Although many efforts have been made, there are only a few reports about the construction of nanostructures on carbon nanotube film surfaces. The big challenge for constructing on carbon films is that these carbon assemblies are easy to be dispersed by immersion in a chemical solution. Here, in this paper, we have shown for the first time the fabrication of different kinds of nanostructures, i.e. nanoneedles, nanoparticles, nanospirals, on carbon nanotube films by using facile and cheap electrodeposition method and precise physical deposition method. We pretreat the films by an electrical method to strengthen the films to avoid dispersion during the electrodeposition process. These composite films are still very flexible after coating with nanostructures. Compared with those precise physical deposition methods, the facile electrodeposition method is more suitable for constructing nanostructures on carbon nanotube films, due to the low requirement for planeness of films. It is interesting to find that these nanostructures can endow superhydrophobicity or higher conductivity for these flexible composite films, which greatly broaden the potential applications for carbon nanotube films in the fields of battery, moisture self-cleaning, electrostatic energy harvesting, and enhancing condensation heat transfer for more efficiency of energy utilization, environmental, and thermal management.     

阿霉素的光谱电化学研究

利用循环伏安、紫外可见光谱电化学、荧光光谱电化学、圆二色光谱电化学等方法研究了阿霉素(ADM)在石墨电极上的电化学行为.结果发现,阿霉素在+0.2～+0.7V和-0.2～-0.7V范围内分别出现一对氧化还原峰.正电位下,蒽环上的酚羟基发生单电子氧化,并伴随后续化学反应.负电位范围内,阿霉素经历ECE电极反应过程,即蒽醌经单电子还原生成半醌自由基,半醌可发生不可逆的化学反应,脱去配氧糖基,转变为7-去氧柔毛霉醌(7-deoxyadriamycinone),后者在更负的电位下形成一对可逆的新的氧化还原峰.     

探测束偏转光谱电化学

评述了探测束偏转光与电化学手段相结合作为一种现场的光谱化学技术关研究电极／电解质界面上的应用。分别从实验装置、偏转原理、影响因素及其应用等方面加以论 。共引用文献５６篇。     

Structure and thermodynamics of carbon and carbon/silicon precursors to nanostructures

The structures at the Hartree-Fock level, as well as the energetics, are reported for the unsaturated system C(36)H(16), its Si-doped analogue C(32)Si(4)H(16), and several smaller, unsaturated fragments. Structural effects on the electronic distribution are discussed in terms of a localized orbital energy decomposition. The standard heats of formation are calculated based on homodesmic and isodesmic reactions and the G2(MP2,SVP) method with a valence double-zeta plus polarization basis. The origin of the observed explosion of the all-carbon system (C(36)H(16)) to form carbon nanotubes was investigated by exploring a possible initial reactive channel (dimerization), which could lead to the formation of the observed onion-type nanostructures.     

Effect of carbon nanostructures on the carbonization of polyacrylonitrile

Composite materials based on polyacrylonitrile with carbon nanofillers (technical-grade carbon, thermally expanded graphite, carbon nanotubes) were synthesized. A carbonization of film and fiber composite samples in the temperature range 20–1000°C provided a noticeable increase in the thermal stability of fibers and a rise in the electrical conductivity of the composite material. Dependences of the degree of carbonization on the concentration of nanostructures, type of material, and nature of modifier were determined. Differential-thermal and X-ray diffraction analyses revealed the formation of oriented nucleus structures of turbostratic carbon in the temperature range 450–550°C.     

Comparison of different carbon nanostructures influence on potentiometric performance of carbon paste electrode

Recently, different carbon nanomaterials were introduced for construction of electrochemical sensors. In this study, the influence of carbon nanomaterial on performance of carbon paste potentiometric electrode was investigated. In this manner, different kinds of carbon nanomaterial, i.e., graphene, graphene oxide and carbon nanotube (CNT) were used as a conduction phase in carbon paste electrode. Then, potentiometric characteristics of the corresponding paste electrodes such as calibration slope, linear range, detection limit, response time and stability were compared with each other. The results appeared comprehensive findings about the role of electrode’s content in electrochemical performance.     

Spectroelectrochemistry study on the electrochemical reduction of ethidium bromide.

The electrochemical reduction mechanism of ethidium bromide was first studied by spectroelectrochemistry. This reduction was proved to be a two-step process by cyclic voltammetry, differential pulse voltammetry and spectroelectrochemistry, in which each step was proved to be a one-electron transfer process by a spectropotentiostatic fluorescence technique. Hydroethidine was confirmed to be the final product by comparing the spectrum of the product of the electrochemical reduction to that of the product of the chemical reduction of ethidium bromide, and a carbon-centered radical was concluded to be a reasonable intermediate product during the electrochemical reduction of ethidium bromide.     

Biomimetic assemblies of carbon nanostructures for photochemical energy conversion

This feature article summarizes our recent accomplishments in the field of carbon nanostructures, fullerenes and carbon nanotubes, as integrative components in multifunctional hybrid cells that bear large promise for applications as photochemical energy conversion systems.     

Spectroelectrochemistry for studying electrochemiluminescence mechanism

UV–Vis spectroelectrochemistry (SEC) was introduced for the first time into the study of electrochemiluminescence (ECL) mechanisms of nitrogen heterocyclic compounds. Uracil and its two derivatives, 5-fluorouracil and 1-methyl-uracil, were chosen as model molecules in the ECL mechanism study. SEC revealed that the substitution of hydrogen at N(1) and the destruction of conjugate heterocyclic ring were very important for ECL activities of uracils. On the basis, a new ECL mechanism was proposed for the uracils. The successful explanation of ECL mechanism for the model molecules by employing SEC indicates that SEC would play an important role in future ECL mechanism studies.     

Controlled modification of multiwalled carbon nanotubes with Zno nanostructures

Multiwalled carbon nanotubes (MWNTs) have been successfully modified with ZnO nanostructures by zinc-ammonitum complex ion covalently attached to the MWNTs through the C-N bonds. Flower-like ZnO on the tips of MWNTs and ZnO nanoparticles on the surface of MWNTs have been obtained, respectively, via adjusting the reaction time. The modified MWNTs have been characterized with X-ray diffraction, scanning electron and transmission electron microscopy. A growth mechanism has been proposed in which the soaking time plays a key role in controlling the size, morphology, and site of ZnO nanostructures. Photoluminescence properties of the as-synthesized products have also been investigated.     

Recent advances in carbon nanostructures prepared from carbon dioxide for high-performance supercapacitors

The burgeoning global economy during the past decades gives rise to the continuous increase in fossil fuels consumption and rapid growth of CO₂ emission,which demands an urgent exploration into green and sustainable devices for energy storage and power management.Supercapacitors based on activated carbon electrodes are promising systems for highly efficient energy harvesting and power supply,but their promotion is hindered by the moderate energy density compared with batteries.Therefore,scalable conversion of CO₂ into novel carbon nanostructures offers a powerful alternative to tackle both issues:mitigating the greenhouse effect caused by redundant atmospheric CO₂ and providing carbon materials with enhanced electrochemical performances.In this tutorial review,the techniques,opportunities and barriers in the design and fabrication of advanced carbon materials using CO₂ as feedstock as well as their impact on the energy-storage performances of supercapacitors are critically examined.In particular,the chemical aspects of various Cv2 conversion reactions are highlighted to establish a detailed understanding for the science and technology involved in the microstructural evolution,surface engineering and porosity control of CO₂-converted carbon nanostructures.Finally,the prospects and challenges associated with the industrialization of CO₂ conversion and their practical application in supercapacitors are also discussed.     

抗癌药物柔红霉素的光谱电化学研究

采用现场光谱电化学技术,结合循环伏安和红外光谱等手段,研究了柔红霉素的电极过程,并提出了可能的还原机理.结果表明,柔红霉素的还原途径与其浓度存在一定的联系:稀溶液的还原经历一ECE过程--得到两个电子还原为柔红霉氢醌后,发生化学反应脱去7位上的糖基侧链,得到的7-去氧柔红霉醌继续被还原,生成的自由基中间体可发生歧化反应或通过分子间缔合而稳定;当溶液浓度较大时,柔红霉素分子在得到一电子生成半醌自由基中间体后,以其双分子缔合物的形式稳定存在.     

去甲肾上腺素的光谱电化学研究

本文用平行入射式光谱电化学方法，测定了去甲肾上腺素的热力学常数Ｅ和ｎ值，用ｎ＾２＋作为自由基稳定剂，讨论了其通过一个电子传递产生半醌自由基中间体的电极反应机理并结合其它电化学方法，证明了ＮＥ在电极上以传质扩散为主的准可逆过程。     

甲基橙的光谱电化学研究

现代电化学技术，如计时电势法、计时电流法、循环伏安法，包括薄层中的各种电化学方法广泛用于研究电化学反应机理及各种后行均相化学反应动力学，并卓见成效[1-3]，但这些方法的应用，一般均需复杂的数据处理．薄层光谱电化学法把中间产物和终产物局限在薄层溶液中，可直接检测其浓度变化，相比之下，在动力学研究方面显示了其特殊的优越性[4-7]．甲基检是一种偶氨化合物，常用作酸碱指示剂，其电氧化还原性质未见报导过．本文采用薄层光谱电化学法，研究它的电极反应机理．1实验部分仪器和试剂UV－3000型紫外可见分光光度计，X－Y函数…