聚氨酯接枝多壁碳纳米管的制备及表征

采用两步法成功地将聚氨酯分子链以共价键连接到碳纳米管表面. 首先将聚丙烯酰氯通过与强酸氧化后多壁碳纳米管表面产生的羟基及少量羧基之间的化学反应共价接枝到碳纳米管表面; 然后将接枝到碳纳米管表面的聚丙烯酰氯与端羟基聚氨酯发生酯化反应, 实现了聚氨酯对碳纳米管的表面共价接枝. 采用傅里叶变换红外光谱(FTIR)、透射电镜(TEM)、扫描电镜(SEM) 和热重分析(TGA)等对接枝后的产物进行了表征, 结果表明, 聚氨酯已共价接枝到碳纳米管表面, 被接枝的聚合物的含量接近90%.     

卟啉和酞菁修饰的单壁碳纳米管的合成及光谱性质

利用5-(4-氨基苯基)-10,15,20-三(3,5-二辛氧基苯基)卟啉和2,9,16-三叔丁基-23-氨基锌(Ⅱ)酞菁通过酰胺键连接方式同时对单壁碳纳米管进行共价修饰, 通过红外光谱、拉曼光谱、X射线光电子能谱和透射电镜对所得碳纳米管复合物进行了表征, 证实了其结构. 紫外-可见吸收光谱和荧光光谱分析表明, 光活性分子卟啉和酞菁均与单壁碳纳米管之间存在较强的电子效应. 经卟啉和酞菁共同修饰的单壁碳纳米管复合物比卟啉和酞菁单独修饰的碳纳米管复合物的吸光范围更宽, 而且分散性较好(309 mg/L), 是潜在的光电转换材料.     

meso-四(4-酰肼基苯基)卟啉及其金属配合物共价和非共价修饰多壁碳纳米管

采用新方法合成了meso-四(4-酰肼基苯基)卟啉及其金属配合物, 通过化学键将酰肼卟啉上的酰肼基与活化的多壁碳纳米管(MWNTs)发生酰胺化反应, 从而得到卟啉共价化学修饰的多壁碳纳米管复合物; 利用卟啉环上的π电子与多壁碳纳米管管壁上的π电子通过π-π堆积效应, 得到卟啉非共价化学修饰的碳纳米管复合物. 通过红外光谱、紫外和荧光光谱对比分析, 发现在卟啉与碳纳米管间存在强烈的电子效应, 且非共价修饰的卟啉-碳纳米管复合物的荧光猝灭率更高.     

金属卟啉化学共价和非共价修饰多壁碳纳米管

合成了5-(4-羟基苯基)-10,15,20-三苯基卟啉锌配合物,与活化的多壁碳纳米管(MWNT)发生酯化反应,从而得到金属卟啉有机共价化学修饰的多壁碳纳米管复合物;利用金属卟啉环上的π电子与多壁碳纳米管管壁上的π电子通过π-π堆积效应,得到金属卟啉有机非共价修饰的多壁碳纳米管复合物.通过透射电镜(TEM)考察了金属卟啉-多壁碳纳米管复合物的形貌特征;通过红外光谱对产物的化学结构进行了表征;通过紫外光谱、荧光光谱和热失重分析(TGA)对比分析了两类复合物,发现非共价修饰的金属卟啉-碳纳米管复合物的荧光淬灭率更高,非共价修饰的金属卟啉-碳纳米管复合物中卟啉的含量比较高.     

金属卟啉有机共价和非共价修饰多壁碳纳米管

合成了5-(4-羟基苯基)-10,15,20-三苯基卟啉锌配合物, 与活化的多壁碳纳米管(MWNT)发生酯化反应, 从而得到金属卟啉有机共价化学修饰的多壁碳纳米管复合物; 利用金属卟啉环上的π电子与多壁碳纳米管管壁上的π电子通过π-π堆积效应, 得到金属卟啉有机非共价修饰的多壁碳纳米管复合物. 通过透射电镜(TEM)考察了金属卟啉-多壁碳纳米管复合物的形貌特征; 通过红外光谱对产物的化学结构进行了表征; 通过紫外光谱、荧光光谱和热失重分析(TGA)对比分析了两类复合物, 发现非共价修饰的金属卟啉-碳纳米管复合物的荧光淬灭率更高, 非共价修饰的金属卟啉-碳纳米管复合物中卟啉的含量比较高.     

聚苯胺共价接枝碳纳米管负载Pt催化剂的制备及对甲醇电催化性能的研究

以氨基化的碳纳米管为基体,通过界面聚合方法将聚苯胺共价接枝于碳纳米管表面,负载催化剂颗粒Pt. 通过透射电镜(TEM)、X射线衍射(XRD)及电化学方法对催化剂进行了表征. TEM结果表明通过界面聚合的方法可以使聚苯胺均匀地接枝于碳纳米管表面. 电化学测试结果表明,碳纳米管共价接枝聚苯胺作为载体可以提高催化剂的抗CO中毒性能,有利于对甲醇的催化氧化. 研究其对甲醇的催化活性,并与商业的JM(Pt/C)催化剂进行了对比. 结果表明,碳纳米管共价接枝聚苯胺,有效提高了催化剂的稳定性,延长催化剂的寿命.     

聚苯乙烯接枝修饰碳纳米管

本文利用碳纳米管的高比表面性质,使多壁碳纳米管(MWNT)表面吸附大量苯乙烯和过氧化苯甲酰(BPO)后在90℃加热,合成聚苯乙烯(PS)接枝修饰的MWNT。并采用透射电镜(TEM),高倍透射电镜(HR-TEM),场发射扫描电镜(FEW SEM),拉曼光谱(RAMAN),X光电子能谱(XPS),热重(TG)等对功能化后的MWNT进行了分析,证明了确实有大量的PS通过共价键接枝在MWNT表面。     

四取代羧基酞菁锌与白蛋白共价结合物的制备与光谱性质

通过成酰胺键的方式制备了一系列含羧基酞菁和白蛋白(牛血清白蛋白(BSA),人血清白蛋白(HSA))之间的共价结合物,所涉及到的酞菁分别是α-四(4-羧基苯氧基)酞菁锌(1)和α-四[4-(2-羧基乙基)苯氧基]酞菁锌(3),以及它们相应的β位四取代酞菁锌(化合物2和4).比较了游离酞菁以及它们的白蛋白结合物在磷酸盐缓冲溶液(PBS)中的光谱性质.结果表明,当酞菁被共价固定于白蛋白大分子上之后,展现出比游离酞菁更明显的单体特征吸收,而且结合物中的酞菁光谱特征不受体系pH值变化的影响.羧基在酞菁环上的取代位置,对酞菁与白蛋白结合前后的光谱转变幅度有影响,α位取代比β位取代更有利于光谱的变化.化合物1和3的白蛋白共价结合物在PBS溶液中甚至呈现出单体形式为主的光谱特征,Q带最大吸收波长分别位于697和706nm附近.     

多壁碳纳米管功能化及其在电化学葡萄糖传感器中的应用

利用硅烷偶联剂的表面修饰技术,将氨基丙基三乙氧基硅烷(APS)共价接枝到酸处理后的碳纳米管的表面.红外光谱数据证实了该反应的可行性.修饰后的碳纳米管在水中具有良好的分散性.利用西夫碱反应将氨基化的碳纳米管与醛基化的葡萄糖氧化酶共价层层自组装到电极表面,获得灵敏度可控的葡萄糖传感器.用电化学交流阻抗法和扫描电镜对成膜过程...     

聚合酞菁铁/多壁碳纳米管复合材料的制备及氧还原催化性能

采用高效、 便捷的微波合成法制备了4种不同结构的聚合酞菁铁/多壁碳纳米管(Poly-FePc/MWCNTs)复合材料并进行了表征. 结果表明, 聚合酞菁铁均匀地包裹在多壁碳纳米管上. 利用线性扫描电位法(LSV)和电化学阻抗法(EIS)对材料的氧还原催化活性进行了研究, 发现FePPc/MWCNTs复合材料具有最好的氧还原催化活性. 采用X射线光电子能谱(XPS)和X射线吸收精细结构光谱(XAFS)研究了Poly-FePc/MWCNTs复合材料中酞菁铁结构变化与氧还原催化性能的相关性. 结果表明, FePPc/MWCNTs复合材料中Fe-N₄接近平面结构, 聚合酞菁铁能够更好地与MWCNTs产生协同作用, 从而加速氧还原过程中电子的转移, 提高氧还原活性.     

Allyloxyporphyrin‐Functionalized Multiwalled Carbon Nanotubes: Synthesis by Radical Polymerization and Enhanced Optical‐Limiting Properties

Allyloxyporphyrin‐functionalized multiwalled carbon nanotubes (MWCNT‐TPP) were synthesized by radical polymerization and characterized by FTIR, UV/Vis absorption, and X‐ray photoelectron spectroscopy; elemental analysis; TEM; and thermogravimetric analysis. Z‐scan studies revealed that this nanohybrid exhibits enhanced nonlinear optical (NLO) properties compared to a control sample consisting of a covalently unattached physical blend of MWCNTs and porphyrin, as well as to the separate MWCNTs and porphyrin. At the wavelengths used, the mechanism of enhanced optical limiting likely involves reverse saturable absorption, nonlinear scattering, and photoinduced electron/energy transfer between the MWCNTs and the porphyrin. The role of electron/energy transfer in the NLO performance of MWCNT‐TPP was investigated by Raman and fluorescence spectroscopy.     

CNT-based organic-inorganic composite materials with optoelectronic functionality

This paper focuses on the fabrication of organic-inorganic composite materials with optoelectronic functionality based on carbon nanotubes (CNTs) by chemical and physical modifications. The one-dimensionally (1D) ordered composites of rare earth phthalocyanine compounds (RePc₂) encapsulated by MWCNTs were obtained using a simple capillary filling method. The CNT-templated assembly of RePc₂ nanowires was performed by a phase-separation method. Two other kinds of organic-inorganic 1D-ordered optoelectronic composites were prepared using the template method: coating MWCNTs with a fluorescent poly(tripheny lamine) related co-polymer can be realized via a facile phase-separation strategy: 1D hy brid of bamboo-shaped CNTs covalently bound to RePc₂. The relationship between the microstructure of the obtained 1D-ordered composites and optoelectronic properties was studied, and it was found that these ordered composites exhibited enhanced photoconductivity due to the charge transfer between the composite components.     

Electrocatalysis of Puerarin on a Nano-CeO2/MWCNTs Composite Modified Electrode and Its Determination in Pharmaceutical Preparations

A good route for the fabrication of CeO₂ nanoparticles (nano‐CeO₂)/multi‐walled carbon nanotubes (MWCNTs) modified glassy carbon electrodes (GCE) was proposed. MWCNTs are used to immobilize nano‐CeO₂. What′s more, with the addition of the MWCNTs, the agglomeration level of CeO₂ nanoparticles can be reduced, the extremely large surface area can be obtained and the electron transfer rate can be increased. The morphological characterization of nano‐CeO₂/MWCNTs was examined by scanning electron microscopy (SEM). The performances of the nano‐CeO₂/MWCNTs/GCE were characterized with cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and typical amperometric response (i‐t). The potential utility of the constructed electrodes was demonstrated by applying them to the analytical determination of puerarin concentration. The catalytic oxidation of puerarin has a better result on nano‐CeO₂/MWCNTs/GCE because of the synergistic effect of nano‐CeO₂ and MWCNTs. An optimized limit of detection of 8.0×10^?9 mol/L was obtained at a signal‐to‐noise ratio of 3 and with a fast response time (within 3 s). Additionally, the nano‐CeO₂/MWCNTs/GCE exhibited a wide linear range from 0.04 to 6.0 μmol/L and high sensitivity.     

The effects of carbon nanotubes on the electrocatalysis of hydrogen peroxide by metallo-phthalocyanines

The pre-grafted screen-printed gold electrode modified with phenyl-amino monolayer was investigated for covalent immobilization of phenyl-amine functionalized single-walled carbon nanotubes (PA-SWCNT) and metal tetra-amino phthalocyanine (MTAPc) using Schiff-base reactions with benzene-1,4-dicarbaldehyde (BDCA) as cross-linker. The PA-SWCNT and MTAPc modified electrodes were applied as hybrids for electrochemical sensing of H₂O₂. The step-by-step fabrication of the electrode was followed using electrochemistry, impedance spectroscopy, scanning electron microscopy and Raman spectroscopy and all these techniques confirmed the fabrication and the immobilization of PA-SWCNT, MnTAPc and CoTAPc onto gold surfaces. The apparent electron transfer constant (k_app) showed that the carbon nanotubes and metallo-phthalocyanines hybrids possess good electron transfer properties compared to the bare, pre-grafted and the MTAPc modified gold electrode surfaces without PA-SWCNT. The electrochemical sensing of hydrogen peroxide was successful with PA-SWCNT-MTAPc hybrid systems showing higher electrocatalytic currents compared to the other electrodes. The analytical parameters obtained using chronoamperometry gave good linearity at H₂O₂ concentrations ranging from 1.0 to 30.0 μmol L⁻¹. The values for the limit of detection (LoD) were found to be of the orders of 10⁻⁷ M using the 3δ for all the electrodes. The PA-SWCNT-MTAPc modified SPAuEs were much more sensitive compared to PA-MTAPc modified SPAuEs.     

Preparation of TiO2 nanosheet-carbon nanotube composite as immobilization platform for both primary and secondary antibodies in electrochemical immunoassay

TiO₂ nanosheets (TNSs) were synthesized and deposited on multi-wall carbon nanotubes (MWCNTs) to form a nano-composite through a hydrothermal method, followed by the characterization with various spectroscopic and microscopic techniques. The TNS-MWCNT composite was then applied as not only an electrode scaffold to immobilize primary antibody, but also as a carrier to load secondary antibody and horseradish peroxidase (HRP). In both cases, bis(sulfosuccinimidyl) suberate sodium salt acted as an amino cross-linker to covalently bind the biomolecules on TNS-MWCNT composite through their surface primary amino groups. After the sandwich-type immunoreaction, HPR was quantitatively captured on the electrode surface via the binding between secondary antibody and antigen, and electrochemical response of the immunosensor was then amplified by a H₂O₂ mediated HRP catalytic reaction. Using α-Fetoprotein as a model analyte, a linear range between 0.005 and 320 ng mL⁻¹ with a detection limit of 2.0 pg mL⁻¹ was achieved by differential pulse voltammetry. The improved immunosensor performance could be attributed to the biocompatibility and high specific surface area of TNS, and excellent electrical conductivity of MWCNTs, which accelerated the electron transfer at the electrode surface.     

Hydrothermal Synthesis of Three Dimensional Graphene‐Multiwalled Carbon Nanotube Nanocomposite for Enhanced Electro Catalytic Oxidation of Caffeic Acid

Three dimensional graphene‐multiwalled carbon nanotube nano composite (3DG/MWCNTs−Nc) was synthesized by simple hydrothermal method for the amperometric determination of caffeic acid (CA). The prepared nanocomposite was characterized by scanning electron microscopic technique (SEM), ultraviolet‐visible spectroscopy (UV), Raman spectroscopy and infrared spectroscopy (IR). Moreover, the interfacial electron transfer properties of the modified electrode were carried out by the electro chemical impedance spectroscopy (EIS). Besides, the electro chemical performance of the modified electrode was carried out by the cyclic voltammetry (CV) and amperometric (i‐t ) technique. The proposed electrode was exhibited an enhanced electrocatalytic activity towards the detection of CA. Under the optimal condition, the 3DG/MWCNTs−Nc modified electrode displayed a linear range from 0.2 to 174 μM, detection limit (LOD) 17.8 nM and sensitivity of 5.8308 μA μM⁻¹ cm⁻² and on applied potential + 0.2 V. These result showed, 3DG/MWCNTs−Nc modified electrodes showed good repeatability, reproducibility, and higher stability. In addition, the fabricated electrode was then successfully used to determine the CA in real samples with satisfactory recoveries. Which suggests that the 3DG/MWCNTs−Nc as a robust sensing materials for the electrochemical detection of CA.     

多壁碳纳米管负载TiO2的光催化脱硝性能

采用溶胶凝胶法制备了多壁碳纳米管负载TiO₂ （MWCNTs/TiO₂）,并利用透射电镜、X射线光电子能谱、X射线衍射和紫外-可见漫反射光谱对样品进行了表征。结果表明,MWCNTs/TiO₂晶型以锐钛矿为主,MWCNTs的引入会限制TiO₂晶粒的生长。另外,MWCNTs/TiO₂的光吸收边向长波区域偏移。针对模拟烟气,在固定床光催化反应器中对采用涂覆处理的MWCNTs/TiO₂的光催化脱硝性能进行了实验研究。结果表明,NO初始浓度较低时,光催化脱硝效率较高,SO₂的存在可抑制光催化脱硝过程,而O₂及H₂O则有促进作用。在最佳实验条件（73 mg/m³ NO,8% O₂,5% H₂O）下,光催化脱硝效率可达46%。提出了光催化脱硝反应机理。     

Relationship between Carbon Nanotube Structure and Electrochemical Behavior: Heterogeneous Electron Transfer at Electrochemically Activated Carbon Nanotubes

The electrochemical activation of multiwalled carbon nanotubes (MWCNTs) (at potentials of 1.5–2.0 V vs Ag/AgCl for 60–360 s) results in significantly increased rate constants ( ) for heterogeneous electron‐transfer with [Fe(CN)₆]^3?/4? (from 8.34×10^?5 cm s^?1 for as‐received MWCNTs to 3.67×10^?3 cm s^?1 for MWCNTs that were electrochemically activated at 2.0 V for 180 s). The increase in the value of arises from the introduction of wall defects exposing edge planes of the MWCNTs, as observed by high‐resolution TEM. The density of the edge plane defects increases from almost zero (for as‐received MWCNTs) to 3.7 % (for MWCNTs electrochemically activated at 2.0 V for 180 s). High‐resolution X‐ray photoelectron spectroscopy (HR‐XPS), Raman spectroscopy, and electrochemical impedance spectroscopy were used to gain a better understanding of the phenomena. HR‐XPS revealed that the increase in electrochemical activation potential increases the number of oxygen‐containing groups on the surface of carbon nanotubes.     

Electrochemical DNA Biosensors Based on Palladium Nanoparticles Combined with Carbon Nanotubes

Palladium nanoparticles, in combination with multi‐walled carbon nanotubes (MWCNTs), were used to fabricate a sensitivity‐enhanced electrochemical DNA biosensor. MWCNTs and palladium nanoparticles were dispersed in Nafion, which were used to modify a glassy carbon electrode (GCE). Oligonucleotides with amino groups at the 5′ end were covalently linked onto carboxylic groups of MWCNTs on the electrode. The hybridization events were monitored by differential pulse voltammetry (DPV) measurement using methylene blue (MB) as an indicator. Due to the ability of carbon nanotubes to promote electron‐transfer and the high catalytic activities of palladium nanoparticles for electrochemical reaction of MB, the sensitivity of presented electrochemical DNA biosensors was remarkably improved. The detection limit of the method for target DNA was 1.2×10^?13 M.     

Multi-wall carbon nanotube counter electrodes for dye-sensitized solar cells prepared by electrophoretic deposition

In this study, electrophoretic deposition (EPD) was employed to fabricate multi-wall carbon nanotube (MWCNT) counter electrodes (CEs) for dye-sensitized solar cells (DSSCs). Firstly, raw MWCNTs were functionalized by means of an acid mixture solution and then subjected to EPD. The results obtained from Raman spectroscopy, Fourier transform infrared spectroscopy, field-emission scanning electron microscope, and cyclic voltammogram demonstrated that the defects and open ends on the MWCNTs can be obtained via chemical functionalization and thus facilitate the enhancement in the electrocatalytic activity for I₃⁻ reduction of MWCNT CEs. In addition to optimizing chemical functionalization of MWCNTs surface, the optimal thickness of MWCNT CEs prepared by EPD was also investigated. Additionally, consecutive cyclic voltammetric tests demonstrated that the MWCNT CE fabricated by EPD possessed excellent electrochemical stability. In comparison with MWCNT CEs fabricated by tape-casting approach, MWCNT CEs prepared by EPD presented a superior adhesion between MWCNT deposits and conducting glass substrates. Therefore, MWCNT CEs fabricated by EPD can be of great potential for use in low-cost plastic DSSCs.