有机两相法制备巯基羧酸修饰的小尺寸贵金属纳米粒子

以生物相容性较好的巯基羧酸分子为保护剂、NaBH4为还原剂,采用有机两相法制备金属纳米粒子,实现了对纳米粒子的表面功能化。该方法制备的纳米材料粒径小(5 nm),单分散性好。讨论了巯基羧酸与金属前驱体之间的投料比、还原剂NaBH4的量以及巯基羧酸分子链长等因素对纳米粒子形貌的影响。除Au外,该方法还适用巯基羧酸对Ag、Pt和Pd等多种纳米粒子的表面修饰。     

一维金纳米线的自组装研究

以管径为20～40nm的多壁碳纳米管为模板,在经巯基修饰的碳纳米管表面定向沉积一薄层纳米金微粒,从而制得了一维金纳米线,并对纳米金线的自组装原理进行了研究.同时用XPS和TEM对所获得的碳基金纳米复合线的化学组成及微观结构进行了分析和表征.实验表明,纳米金微粒可在接枝巯基的碳纳米管表面自组装形成结构较好的纳米线.     

假冠醚结构稳定的金纳米粒子在MWNTs表面的自组装

叙述了一个有效的由聚乙二醇形成假冠醚结构稳定的金纳米粒子在多壁碳纳米管(MWNTs)表面自组装研究。MWNTs在H2SO4-HNO3溶液中经氧化修饰上羧基和羟基之后,以光化学合成和晶种媒介生长法制备的胶体金纳米粒子被直接附着在其表面上。通过对Au/MWNTs复合物的TEM表征,研究了金纳米粒子尺寸对MWNTs表面自组装的影响;同时探讨了金纳米粒子对MWNTs表面自组装的驱动力。     

自组装制备准一维金纳米复合导线

为了获得性能优异的微电子材料,通过化学镀和自组装制备了平均直径小于50 nm的准一维金纳米复合导线.通过实验证实了金纳米线的形成机制,即纳米金复合导线是纳米金微粒在巯基化的碳纳米管表面通过自组装而形成的.碳纳米管分别依次与浓硝酸和浓硫酸的混酸(1:4)、LiAlH4、PBr3和NaHS反应,可得到活性基团巯基修饰的碳纳米管.分别用XPS、TEM、XRD等对实验结果进行了表征.     

银纳米粒子尺寸对多壁碳纳米管自组装的影响

研究了以胶体银纳米粒子为前体在多壁碳纳米管(MWNTs)表面进行的自组装及其银粒子尺寸对自组装的影响。结果表明:银粒子与MWNTs的平均直径之比≤1/3时,能够获得较好的Ag/MWNTs一维复合物材料,而且透射电镜(TEM)直接观察到银纳米粒子的自组装及其生长优先在MWNTs端头发生;基于各种技术表征,在N,N-二甲基甲酰胺(DMF)存在下MWNTs功能化的表面存在的羧基、羟基与柠檬酸根的多羧基、羟基基团之间的氢键作用以及疏水作用可能是银纳米粒子自组装的主要驱动力。     

循环伏安法研究银表面自组装膜的致密性

在Ag电极表面制备了3-巯基丙基三甲氧基硅烷(MPS)自组装单分子膜,通过循环伏安曲线(CV)、接触角等方法对修饰电极的电化学性能、组装膜的致密性等进行了研究.结果表明:修饰后电极的CV曲线峰电流减小、还原峰位发生负移及峰电位差增大,说明MPS已经在Ag电极表面成膜,对电子传输具有明显的抑制作用.膜的致密性受组装液浓度及组装时间的影响,当MPS的浓度为0.1 mmol/L、组装时间为6 h时,抑制电化学反应的效果较好,组装膜成膜状况较为理想.对不同水解时间接触角的分析表明,水解时间不同,MPS尾基的水解自聚度不同,延长水解时间能提高组装膜的致密度.     

含氯低pH值溶液中BDT自组装膜对铜电极的缓蚀行为

采用分子自组装技术,在铜电极表面形成一层1, 3-二巯基硫醇(BDT)单分子自组装膜.通过交流阻抗、极化曲线和循环伏安等电化学方法探讨该自组装膜在3%NaCl溶液中对铜电极的缓蚀作用.实验表明:BDT能够有效地组装到铜的表面形成单分子自组装膜,BDT自组装膜能有效地抑制铜基底在3%NaCl腐蚀介质以及酸性NaCl溶液中的腐蚀行为;缓蚀效率随组装时间的延长逐渐升高并趋于稳定,在pH值较低的溶液中仍具有较好的缓蚀效果;当BDT浓度为1.0×10-2 mol/L、组装时间为40 h时,铜电极的腐蚀电流最小,缓蚀效率最好.     

对氨基苯甲酸在银纳米粒子二维有序阵列中的光谱研究

用氢气还原氧化银的方法合成了粒径约为100 nm的银纳米粒子,在表面经聚乙烯吡啶修饰的玻璃片上以自组装的方式构筑了银纳米粒子的单层二维有序阵列。经对氨基苯甲酸修饰后,进而又构筑了银纳米粒子的双层二维有序阵列。采用透射电镜(TEM)、扫描电镜(SEM)和紫外-可见光谱(UV-Vis)进行了表征。二维有序阵列的表面增强拉曼光谱研究表明:对氨基苯甲酸在银粒子上垂直吸附,电磁场增强对表面增强拉曼效应起主导作用。     

腐蚀微生物硫酸盐还原菌在不同荷电状态表面的初始附着行为

研究了材料表面电荷对硫酸盐还原菌(SRB)初始附着行为的影响。分别将6-胺基-1-己烷硫醇,6-巯基-1-己醇和6-巯基己酸修饰在Au电极表面,形成不同荷电状态的自组装膜(SAMs)。用电化学阻抗(EIS)和扫描电子显微镜(SEM)监测SRB在3种SAMs表面的附着。结果表明,荷正电的SAMs表面有利于SRB的初期附着,而荷负电的SAMs表面则会抑制SRB初期附着并使其可逆附着过程的时间延长。另外,3种表面的电荷转移电阻变化率(△Rct%)可在一定程度上反映SRB的初期附着情况。     

金纳米粒子的组装及光谱特征

通过对玻璃基底的硅烷基化,金纳米粒子被组装到玻璃基底上,SEM表明金纳米粒子在玻璃基底上形成二维的亚单层组装结构.同时又利用聚苯乙烯模板对金纳米粒子进行图案化组装,在玻璃基底上形成"面包圈"结构.     

Structure,surface topography and electrochemical properties of cast films formed by fullerenes and their compositions with salt matrices

Some properties of films based on fullerene and pyridyl substituted fullerenopyrrolidines were studied. Both direct casting and immobilizing electroactive substances in the tetraoctylammonium bromide (TOAB) or tetraphenylphosphonium bromide matrices were used for modification of the ITO electrode surface. In accordance with X-ray diffraction, pyridyl substituted fullerenopyrrolidines are amorphous, and the lamellar structure of TOAB is retained when fullerene is present in the film. The differences, which are observed in the absorption spectra of the cast coatings of the individual fullerenes or fullerenes in the TOAB matrix as compared with solution spectra testify to the electronic interaction between fullerene molecules in a solid phase. At that, the quaternary ammonium salt participates immediately in the coating self-organization. Atomic force microscopy showed that both the solution composition and addends in the C₆₀ molecules influence the film morphology. Disintegration of fullerenes in the TOAB matrix and their interaction with hydrocarbon chains of TOAB provide the hydrophobic surrounding required for reversible electrochemical reduction of fullerene on an electrode in an aqueous solution. The differences observed for C₆₀ embedded in the tetraphenylphosphonium bromide and TOAB films accentuate the role of a layered structure of the matrix for the reversible electrochemical behavior of fullerene in aqueous solution.     

Detection of chemical warfare agent Nitrogen Mustard-1 based on conducting polymer phthalocyanine nanorod modified electrode

A simple method is reported for the detection of chemical warfare agent Nitrogen Mustard-1 (NM-1) by using a modified electrode which was prepared by electrochemically immobilizing copper phthalocyanine (CuPc) into polypyrrole (pPy) in presence of a cationic surfactant cetyltrimethylammonium bromide (CTAB) during the polymerization of pyrrole in an aqueous solution. The surface of the modified and bare electrodes are characterized by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) techniques in order to know the surface morphology and elemental composition of the modified electrodes, respectively. SEM images indicated the presence of nanorods on pPy/CuPc/CTAB sample and EDS study confirmed the nanorods as CuPc. Moreover, EDS study confirmed that the nanorods are only on the pPy matrix and not inside the pPy. FTIR results confirmed the presence of CuPc in pPy film. AC impedance spectroscopy analysis of the modified electrode with NM-1 exhibited more electron transfer resistance. The prepared modified electrode showed good electrochemical activity with NM-1 when compared to the unmodified gold electrode.     

MoO3纳米有机溶胶的制备与光致变色性质研究

采用表面活性剂CTAB对MoO3水溶胶中的纳米粒子进行表面修饰，通过正戊醇萃取制备了MoO3纳米有机溶胶，对制备有机溶胶的条件进行了系统地研究。TEM分析表明，MoO3纳米粒子呈球形，粒径约为40nm，粒度分布均匀。ED分析表明，MoO3纳米粒子为多晶结构。UV-VIS分析表明，MoO3纳米有机溶胶具有较好的光致变色特性。     

Electrochromism of poly(3,4-ethylenedioxythiophene) films on Au nano-brush electrode

Au nano-brush membranes were prepared using a modified template method. Poly(3,4-ethylenedioxythiophene) (PEDOT) films were immobilized by an electropolymerization with the product membrane as the working electrode. The PEDOT film on the nano-brush electrode showed higher electrochromic (EC) coloration compared to the PEDOT film on an Au planar electrode.     

Uniform and Homogeneous Growth of Copper Nanoparticles on Electrophoretically Deposited Carbon Nanotubes Electrode for Nonenzymatic Glucose Sensor

The multiwalled carbon nanotubes thin-film-based electrode was fabricated by electrophoretic deposition and modified with copper(Cu) nanoparticles to fabricate Cu/CNTs nanocomposite sensor for nonenzymatic glucose detection.The expensive glassy carbon electrode was replaced by fluorine-doped tin oxide glass containing CNTs film to confine the Cu nanoparticles growth by electrodeposition through cyclic voltammetry(CV). The ultraviolet visible and X-ray diffraction analysis revealed the successful deposition of Cu nanoparticles on the CNTs-modified electrode. The atomic force microscopy images confirmed the morphology of electrodeposited Cu on CNTs film as uniformly dispersed particles.The electrocatalytic activity of electrode to the glucose oxidation was investigated in alkaline medium by CV and amperometric measurements. The fabricated sensor exhibited a fast response time of less than 5 s and the sensitivity of 314μA mM~(-1)cm~(-2)with linear concentration range(0.02–3.0 mM) having detection limit 10.0μM. Due to simple preparation of sensor, Cu/CNTs nanocomposite electrodes are a suitable candidate for reliable determination of glucose with good stability.     

Pd纳米盘的光热辅助合成及其对乙醇的电催化氧化

以氯化钯(Pd Cl2)为金属前驱体,乙醇为还原剂,十六烷基三甲基溴化铵(CTAB)为稳定剂和导向剂,利用普通市售白炽灯产生的光热作用,辅助合成Pd纳米盘材料。用XRD、TEM、选区电子衍射(SAED)和UV等技术对合成产物进行表征,考察了CTAB用量对纳米Pd微观形貌和尺寸的影响,并通过循环伏安法研究了纳米Pd修饰玻碳电极对乙醇的电催化氧化活性。结果表明,通过改变Pd Cl2和CTAB的摩尔比,可以调控纳米Pd的微观形貌和尺寸;当Pd Cl2与CTAB的摩尔比为1:80,可见光辐照6 h时,得到的Pd纳米盘呈多边形貌,平均粒径为46 nm,对乙醇有较好的电催化活性和抗中毒能力。     

纳米TiO2的改性及其在丙烯酸涂料中的应用

设计了一种改性纳米TiO2方法，先用带双键官能团的硅烷偶联剂WD70和纳米TiO2反应后，在颗粒表面引入可聚合官能团，然后和甲基丙烯酸甲酯、丙烯酸丁酯共聚合使纳米TiO2颗粒改性.研究结果表明，改性提高了纳米颗粒在涂料中的分散程度，降低了涂层的吸水性和透气性.     

Electrochromism of poly(pyrrole) film on Au nano-brush electrode

Au nano-brush membranes were prepared by a modified template method. Poly(pyrrole) (PPy) films were immobilized by an electropolymerization with the product membrane as the working electrode. In contrast to the PPy film on an Au planar electrode, the PPy film on the nano-brush electrode showed a higher electrochemical stability for the continuous cyclic polarization. Based on the measurement of the reflectance using a simple two-electrode device, a fine electrochromic performance including the switching response and repetition stability was obtained from the device with the PPy film on the Au nano-brush electrode.     

Study of the electrochemical properties of a transition metallic ions modified electrode in acidic VOSO4 solution

Graphite material was used as the electrode for an all-vanadium redox flow battery, and the electrode was modified by transition metallic ions to enhance its electrochemical behavior. An porous graphite composite electrode has high specific surface area and high current density. The electrode modified by transition metallic ions has improved catalysis behavior that can catalyze the V（Ⅱ）-V（Ⅴ） redox reaction showed by cyclic voltammograms. This article studied the impedance of the modified electrode by electrochemical impedance spectroscopy （EIS）, and approved that the electrode modified by Co^2＋ and Mn^2＋ has a lower charge transfer resistance than the non-modified electrode. The effect of average particle size distribution is at lower frequencies that the slope of Warburg impedance is reduced by large particle size distribution. The voltage efficiency of the Co^2＋ modified electrode test cell is 81.5%, which is higher than that of the non-modified electrode.     

Preparation of Au/ polypyrrole composite nanoparticles and study of their electrocatalytical reduction to oxygen with (without) lacasse

The colloids of Au/polypyrrole (AuPPy) composite nanoparticles were prepared by oxidizing pyrrole monomer with HAuCl₄ in a cetyltrimethylammonium bromide (CTAB) solution. Scanning electron microscopy (SEM) suggests the AuPPy nanoparticles in the form of regular spheres, approximately 200 nm in diameter. The resulting colloid of AuPPy composite nanoparticles strongly adheres to the surface of Au electrodes and exhibits better electrocatalytical reduction of oxygen than bare Au electrodes. It means that the complex procedures of centrifuge and wash are avoided. Also, no linker molecules are needed and the immobilization of nanoparticles is achieved easily in a single-step procedure. The experimental parameters were optimized with regard to the concentration of pyrrole and HAuCl₄. The direct electron transfer of laccase is observed after it is immobilized on AuPPy modified electrodes by glutaraldehyde. With the help of mediator 2,2′-azino-bis-(3-ethylbenzothiazoline-sulfonic acid) (ABTS), laccase electrode gives an electrocatalytical reduction wave of oxygen at least at 0.8 V. This material is an excellent choice for the design of metal nanoparticle modified electrodes or biosensors