Graphene oxide coated capillary for the analysis of endocrine‐disrupting chemicals by open‐tubular capillary electrochromatography with amperometric detection

A graphene oxide‐coated capillary was fabricated by using 3‐aminopropyltriethoxysilane as the cross‐linking agent. It was used for the separation and detection of three endocrine‐disrupting chemicals, including bisphenol A, 4‐nonylphenol, and 4‐octylphenol by capillary electrochromatography. Due to the hydrophobicity, hydrogen bonding, and π–π interaction between graphene oxide and the analytes, the three analytes could be well separated in pH = 11.0, 20 mmol/L Na₂B₄O₇‐NaOH/methanol mobile phase (50:50, v/v) within 950 s. After preconcentration, the detection limits were 6.7 × 10^?10, 3.3 × 10^?9, and 6.7 × 10^?10 mol/L (S/N = 3) for bisphenol A, nonylphenol, and octylphenol, respectively. The developed method was successfully applied to the determination of the above analytes in water samples. The satisfactory result demonstrated that the graphene oxide coated capillary used in capillary electrochromatography with amperometric detection was convenient to prepare, highly stable, and had good reproducibility.     

Carbon Nanotube Immobilized Electrode Using Amphiphilic Phospholipid Polymer with Anti‐fouling and Dispersion Property for Electrochemical Analysis

A carbon nanotube (CNT)‐modified electrode was fabricated by dropping a dispersion of multi‐walled CNTs in water‐soluble and amphiphilic phospholipid polymer with both dispersing ability and anti‐biofouling property onto a Au electrode. A poly(2‐methacryloyloxyethyl phosphorylcholine‐co‐n‐butyl methacrylate) (PMB) composed from 50 mol% of 2‐methacryloxylethyl phosphorylcholine and 50 mol% of n‐butyl methacrylate (PMB50) was used as dispersing reagent for CNTs. The dispersion of water‐insoluble material by PMB50 and its antifouling effects in electrochemical analysis were investigated. The CNT‐modified electrode showed an anodic peak potential that was shifted negatively and an increase in the current value for the electrolytic oxidation of nicotinamide adenine dinucleotide. In addition, the charge on PMB50 did not inhibit the electrochemical reaction of the redox compounds K₃[Fe(CN)₆], [Ru(NH₃)₆]Cl₃, and hydroxymethylferrocene. Cyclic voltammetry of K₃[Fe(CN)₆] in 4 % bovine serum albumin (BSA) using a bare Au electrode, the anodic peak current was reduced to 47 % of that without BSA. In contrast, the antifouling effect of the PMB50‐coated electrode meant that the current was only reduced to 70 % of that without BSA.     

Electrochemistry and electroanalytical applications of carbon nanotubes: a review.

This review addresses recent developments in electrochemistry and electroanalytical chemistry of carbon nanotubes (CNTs). CNTs have been proved to possess unique electronic, chemical and structural features that make them very attractive for electrochemical studies and electrochemical applications. For example, the structural and electronic properties of the CNTs endow them with distinct electrocatalytic activities and capabilities for facilitating direct electrochemistry of proteins and enzymes from other kinds of carbon materials. These striking electrochemical properties of the CNTs pave the way to CNT-based bioelectrochemistry and to bioelectronic nanodevices, such as electrochemical sensors and biosensors. The electrochemistry and bioelectrochemistry of the CNTs are summarized and discussed, along with some common methods for CNT electrode preparation and some recent advances in the rational functionalization of the CNTs for electroanalytical applications.     

Voltammetric Determination of Sophoridine Based on Gold Nanoparticles/L‐cysteine/ Graphene Modified Glassy Carbon Electrode

A new strategy to make the electrochemical sensor was presented, through combining gold nanoparticles (GNPs) with reduced graphene oxide (rGO) via L‐cysteine (L‐cys) as crosslinker. The resulting electrodes were characterized by scanning electron microscopy (SEM) and electrochemical methods. And it was applied to develop a high‐sensitive electrochemical sensor for determination of sophoridine. Compared with the bare GCE and reduced graphene oxide modified electrode, the resulting electrodes exhibited excellent response toward the oxidation of sophoridine by significantly enhancing the oxidation peak currents and decreasing the overpotential of sophoridine. Under the selected conditions, there exist the linear relation between the oxidation peak currents and sophoridine concentration in the range of 1.0 x 10^‐6～1.0 x 10^‐4 mol L^‐1, with detection limit of 4.0 x 10^‐7 mol L^‐1. At the same time, the method can be successfully applied to the quantitative determination of sophoridine in injection samples and its result is satisfactory.     

Effect of size and protein environment on electrochemical properties of gold nanoparticles on carbon electrodes

We studied the electrochemical properties of gold nanoparticles (GNPs) and their complexes with proteins using square-wave voltammetry. Effect of the nanoparticle size and detection procedure was explored upon the oxidation of GNPs on a glassy carbon electrode (GCE). For pre-characterized GNPs of 13, 35 and 78 nm diameter, the oxidation peak potential was + 0.98, + 1.03 and + 1.06 V vs. Ag/AgCl, respectively. The conjugation of GNPs with four different proteins was verified by UV–Vis spectroscopy and atomic force microscopy indicated the formation of protein shells around GNPs. This process hampered the oxidation of GNPs on bare GCE causing pronounced decrease in the current response by an average factor of 72. GCE modification with carbon nanotubes weakly influenced the sensitivity of GNP detection but resulted in a 14.5-fold signal increase averaged for all GNP–protein complexes. The acidic dissolution and electrodeposition of GNPs or their complexes adsorbed on GCE allowed superior signal amplification directly proportional to nanoparticle size. The results are useful for the optimization of voltammetric analysis of GNP–protein complexes and can be extended to the characterization of other metal nanostructures and their complexes with biological components.     

A Review Featuring Fabrication,Properties and Applications of Carbon Nanotubes (CNTs) Reinforced Polymer and Epoxy Nanocomposites

Carbon nanotubes (CNTs) have long been recognized as the stiffest and strongest man-made material known to date.In addition,their high electrical conductivity has roused interest in the areas of electrical appliances and communication related applications.However,due to their miniature size,the excellent properties of these nanostructures can only be exploited if they are homogeneously embedded into light-weight matrices as those offered by a whole series of engineering polymers.In order to enhance their chemical affinity to engineering polymer matrices,chemical modification of the graphitic sidewalls and tips is necessary.The mechanical and electrical properties to date of a whole range of nanocomposites of various carbon nanotube contents are also reviewed in this attempt to facilitate progress in this emerging area.Recently,carbonaceous nano-fillers such as graphene and carbon nanotubes (CNTs) play a promising role due to their better structural and functional properties and broad range of applications in every field.Since CNTs usually form stabilized bundles due to van der Waals interactions,they are extremely difficult to disperse and align in a polymer matrix.The biggest issues in the preparation of CNTs reinforced composites reside in efficient dispersion of CNTs into a polymer matrix,the assessment of the dispersion,and the alignment and control of the CNTs in the matrix.An overview of various CNT functionalization methods is given.In particular,CNT functionalization using click chemistry and the preparation of CNT composites employing hyperbranched polymers are stressed as potential techniques to achieve good CNT dispersion.In addition,discussions on mechanical,thermal,electrical,electrochemical and applications ofpolymer/CNT composites are also included.     

不同直径碳纳米管的抗电化学氧化性

本文比较了由化学气相沉积法制备的不同直径(在100 nm以内)的多壁碳纳米管(CNT)的抗电化学氧化性.将CNT电极于1.2 V(vs.RHE)下电氧化120 h,记录氧化电流~时间变化曲线;X射线光电子能谱(XPS)分析氧化前后CNT的表面化学组成.结果表明,随着CNT直径的减小,其氧化电流降低,但其中以为10~20 nm的CNT电极氧化电流最小,表面氧的增量也最小,即被氧化的程度最低,抗电化学氧化性最强.根据不同直径CNT的缺陷位、不定型碳的丰度和碳原子的应力能,分析了其抗电化学氧化性差异的原因.     

Facile One‐Pot,One‐Step Synthesis of a Carbon Nanoarchitecture for an Advanced Multifunctonal Electrocatalyst

A one‐pot/one‐step synthesis strategy was developed for the preparation of a nitrogen‐doped carbon nanoarchitecture with graphene‐nanosheet growth on the inner surface of carbon nanotubes (CNTs). The N‐graphene/CNT hybrids exhibit outstanding electrocatalytic activity for several important electrochemical reactions as a result of their unique morphology and defect structures, such as high but uniform nitrogen doping, graphene insertion into CNTs, considerable surface area, and the presence of iron nanoparticles. The high‐yield synthetic process features high efficiency, low‐cost, straightforward operation, and simple equipment.     

Chitosan‐Functionalized Carbon Nanotubes as Support for the High Dispersion of PtRu Nanoparticles and their Electrocatalytic Oxidation of Methanol

Carbon nanotubes (CNTs) were non‐covalently functionalized with chitosan (Chit) and then employed as the support for PtRu nanoparticles. The functionalization was carried out at room temperature without the use of corrosive acids, thereby preserving the integrity and the electronic conductivity of the CNTs. Transmission electron microscopy reveals that PtRu nanoparticles were highly dispersed on the surface of Chit‐functionalized CNTs (CNT‐Chit) with small particle‐size. Cyclic voltammetry studies indicated that the PtRu nanoparticle/CNT‐Chit nanohybrids have a higher electrochemical surface area, electrocatalytic performance, and stability towards methanol oxidation compared to PtRu nanoparticles supported on the pristine CNTs.     

Facile One‐Pot,One‐Step Synthesis of a Carbon Nanoarchitecture for an Advanced Multifunctonal Electrocatalyst

A one‐pot/one‐step synthesis strategy was developed for the preparation of a nitrogen‐doped carbon nanoarchitecture with graphene‐nanosheet growth on the inner surface of carbon nanotubes (CNTs). The N‐graphene/CNT hybrids exhibit outstanding electrocatalytic activity for several important electrochemical reactions as a result of their unique morphology and defect structures, such as high but uniform nitrogen doping, graphene insertion into CNTs, considerable surface area, and the presence of iron nanoparticles. The high‐yield synthetic process features high efficiency, low‐cost, straightforward operation, and simple equipment.     

Dye‐Sensitized Solar Cell Counter Electrodes Based on Carbon Nanotubes

Dye‐sensitized solar cells (DSSCs) have received significant attention from the scientific community since their discovery in 1991. However, the high cost and scarcity of platinum has motivated researchers to seek other suitable materials for the counter electrode of DSSCs. Owing to their exceptional properties such as high conductivity, good electrochemical activity, and low cost, carbon nanotubes (CNTs) have been considered as promising alternatives to expensive platinum (Pt) in the counter electrode of DSSCs. Herein, we provide a Minireview of the CNTs use in the counter electrode of DSSCs. A brief overview of Pt‐based counter electrodes is also discussed. Particular attention is given to the recent advances of counter electrodes with CNT‐based composite structures.     

Hot press transferring of graphene nanoplatelets on polyurethane block copolymers film for electroactive shape memory devices

We report a transferring method of graphene nanoplatelets (GNPs) on polyurethane (PU) block copolymers film. We polymerized PU block copolymer films, and then, a GNP layer, deposited on glossy paper by drop casting, was transferred by hot press from the glossy surface to the synthetized PU substrate. Nanoindentation test showed that GNP coated PU substrate exhibits improved mechanical properties with respect to the neat PU film. When an electric bias was applied to the GNP coating, the heat generated by Joule effect was transferred to the PU substrate showing an electroactive shape recovery effect. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014 , 52, 1100–1106     

碳纳米管的宏量制备及产业化

作为纳米材料的代表之一,碳纳米管因其独特的一维结构具备了优异的力学、电学、热学、光学和反应性能,使其在能源存储与转化、复合材料、多相催化、环境保护及生物医药等领域具有大量的应用潜力.本文总结了多种类型碳纳米管宏量制备的化学及工程原理,并对多壁碳纳米管、单壁碳纳米管、双壁碳纳米管、定向碳纳米管、超顺排碳纳米管、水平超长碳纳米管、掺杂碳纳米管、螺旋碳纳米管、碳纳米管结及碳纳米管/石墨烯杂化物的宏量制备方法进行了评述.同时,对碳纳米管产业化中新的工程问题,如工业标准、环境评估以及产业化进展进行了分析.目前,碳纳米管已经具有成千吨的产能,并广泛应用于锂离子电池电极、导电复合材料、汽车配件和体育用品等领域.尽管如此,高性能的碳纳米管的宏量制备及其配套产业化技术仍有待深入开发,产品需要进一步丰富、市场需要进一步拓展,以望形成大规模纳米产业,促进社会的可持续发展.     

Printing graphene-carbon nanotube-ionic liquid gel on graphene paper: Towards flexible electrodes with efficient loading of PtAu alloy nanoparticles for electrochemical sensing of blood glucose

The increasing demands for portable, wearable, and implantable sensing devices have stimulated growing interest in innovative electrode materials. In this work, we have demonstrated that printing a conductive ink formulated by blending three-dimensional (3D) porous graphene–carbon nanotube (CNT) assembly with ionic liquid (IL) on two-dimensional (2D) graphene paper (GP), leads to a freestanding GP supported graphene–CNT–IL nanocomposite (graphene–CNT–IL/GP). The incorporation of highly conductive CNTs into graphene assembly effectively increases its surface area and improves its electrical and mechanical properties. The graphene–CNT–IL/GP, as freestanding and flexible substrates, allows for efficient loading of PtAu alloy nanoparticles by means of ultrasonic-electrochemical deposition. Owing to the synergistic effect of PtAu alloy nanoparticles, 3D porous graphene–CNT scaffold, IL binder and 2D flexible GP substrate, the resultant lightweight nanohybrid paper electrode exhibits excellent sensing performances in nonenzymatic electrochemical detection of glucose in terms of sensitivity, selectivity, reproducibility and mechanical properties.     

Differential Pulse Voltammetry Determination of Ofloxacin in Human Serum and Urine Based on a Novel Tryptophan‐graphene Oxide‐carbon Nanotube Electrochemical Sensor

The highly sensitive determination of ofloxacin (OFL) in human serum and urine was achieved on a novel tryptophan‐graphene oxide‐carbon nanotube (Trp‐GO‐CNT) composite modified glassy carbon electrode (Trp‐GO‐CNT/GCE). The Trp‐GO‐CNT composite was fabricated, and its morphologies and surface functional groups were characterized by field emission scanning electron microscopy (FE‐SEM) and Fourier transform infrared (FT‐IR) spectroscopy. The electrochemical properties of Trp‐GO‐CNT/GCE were investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The superior electrochemical behaviors of Trp‐GO‐CNT/GCE toward OFL can be mainly assigned to the excellent electrocatalytic activity of Trp, the great conductivity and high surface area of GO and CNT, and the synergistic effect between Trp, GO and CNT. Under optimum conditions, a wide and valuable linear range (0.01–100 μM), a low detection limit (0.001 μM, S/N=3), a good linear relationship (R2>0.999), good stability and repeatability were obtained for the quantitative determination of OFL. Furthermore, the Trp‐GO‐CNT electrochemical sensor was successfully applied to the determination of OFL in human serum and urine samples, and satisfactory accuracy and recovery could be obtained.     

碳纳米管的电化学贮氢性能研究

研究了碳纳米管电极的电化学性能 ,其电化学储氢量达到 2 0 0mAh·g 1且具有高的电化学活性和良好的循环寿命 .采用循环伏安法研究了氢在碳纳米管电极上吸附 /氧化机理 .     

Platinum catalysts prepared with functional carbon nanotube defects and its improved catalytic performance for methanol oxidation

Carbon nanotube (CNT) supported Pt nanoparticle catalysts have been prepared by spontaneous reduction of PtCl6(2-) ion as a result of direct redox reactions between PtCl6(2-) and oxygen-containing functional groups at defect sites of CNTs, which were introduced by chemical and electrochemical oxidation treatment of CNTs. The electrocatalytic properties of as-prepared Pt-CNT catalysts for methanol oxidation were investigated by chronopotentiometry and cyclic voltammetry. Compared with Pt catalysts prepared by hydrogen reduction and electrochemical deposition methods, Pt catalysts synthesized by functional CNT defects show excellent antipoisoning ability and long-term cycle stability.     

Ultrathin gold film deposited on human hair: Derivation from nanoparticles and applications as microsensors

An ultrathin film of gold was grafted on human hair by a chemical liquid deposition method under ambient conditions. The method consisted of the assembling of gold nanoparticles (GNPs) on the adsorptive sites of human hair as seeds and the growth of isolated GNP seeds into a continuous gold layer. The resulting gold film coated hair possessed good conductivity and flexibility, and can be used as a novel gold hair microelectrode (GHME). This electrode inherited some merits of both hair and gold nanoparticles, for instance, good mechanical property, excellent biocompatibility and high surface area. GHME was also proven to exhibit sensitive electrochemical responses toward dopamine and nitric oxide, foreseeing its promising applications in the fields of biomedical analysis.     

新型CNT/nano-TiO_2复合膜电极的制备及其异相电催化性能

采用溶胶-凝胶法制备了碳纳米管/纳米TiO2(CNT/nano-TiO2)复合溶胶,通过提拉法将复合溶胶涂覆在Ti基体上制得CNT/nano-TiO2复合膜修饰电极(C电极),其电化学性能经循环伏安、计时库仑、交流阻抗谱(EIS)等方法研究.研究结果表明,CNT可阻碍nano-TiO2粒子团聚.在循环伏安图中,C电极的氧化还原峰电流比nano-TiO2膜修饰电极(P 电极)的高出两倍多.通过对草酸溶液的异相电催化反应进一步证明C电极比P电极具有更高的电催化活性,而且对双氧水也有很强的异相电催化还原能力.     

一维/二维复合碳载体组成对Pd催化剂甲醇氧化性能的影响

采用固相-液相两步混合法制备了由碳纳米管（CNTs）和石墨烯纳米片（GNPs）组成的CNTs-GNPs复合载体。以乙二醇还原法将Pd纳米粒子沉积于复合碳载体上,制得Pd/CNTs-GNPs催化剂。以透射电子显微镜、X射线衍射及X射线光电子能谱表征催化剂的形貌、组成和结构;以电化学方法考察催化剂的甲醇电氧化性能。结果表明,Pd/CNTs-GNPs（1/4）（GNPs质量分数为1/4）催化剂具有较大的电化学表面积和较高的甲醇电氧化活性,其甲醇氧化峰电流密度可达Pd/CNTs催化剂的1.97倍。催化剂的高活性得益于CNTs-GNPs载体的一维/二维复合结构使Pd纳米粒子具有良好的分散性能。计时电流实验表明,与单一载体负载Pd催化剂相比,复合载体负载Pd催化剂具有较强的抗中毒能力。