微电极研究(Ⅹ)——微盘电极上稳态过程导数伏安法

本文研究了微盘电极上单扫描、一次导教、二次导数及三次导数的稳态扩散电流方程,一次导数的电流峰与扫描速率v成正比,二次导数及三次导数的电流峰分别与v²、v³成正比,从而提高了响应灵敏度,通过它们的波形可以很方便地求得电极反应的标准电极电位,判断反应的可逆性,用碳纤维微盘电极进行了验证,结果与理论方程一致。     

线性扫描伏安法研究(Ⅰ)——微盘电极上准稳态可逆波方程式及其验证

本文报道微盘电极上线性扫描伏安法准稳态可逆波方程式,并成功地进行了验证,理论和实验结果十分符合。     

金电极上偶氮腺嘌呤的电化学行为研究

本文研究了光滑金电极上偶氮腺嘌呤的电化学特性,并确定了相关动力学参数. 在含偶氮腺嘌呤的0.2 mol·L^-1的磷酸盐缓冲液(PBS,pH = 4.0 ~ 10.0）中,发现其循环伏安图上出现一对氧化还原峰. 基于对扫速和伏安峰值电位的分析,结果表明这是一个由吸附控制的可逆偶氮腺嘌呤氧化还原电化学过程. 当pH值从低到高改变时,氧化还原峰值向负电位移动,证实H⁺参与了该反应. 通过进一步实验数据分析和电极表面吸附量计算,发现该反应为分步进行的两电子两质子反应. 最后,通过快速循环伏安扫描方法确定了电化学过程的表观传递系数α和表观速率常数ks.     

铁氰化镧修饰电极的制备及表征

An electroactive polynuclear inorganic compound of rare earth metal hexacyanoferrate, lanthanum hexacyanoferrate (LaHCF), was prepared by electrochemical deposition on the surface of a glassy carbon electrode with a potential cycling procedure. The cyclic voltammogram of LaHCF exhibits a pair of well-defined redox peaks with the formal potential of 208 mV (vs. SCE) at a scan rate of 100 mV/s in 0.2 mol/L NaCl solution and the redox peak currents increase linearly with the square root of the scan rate up to 1000 mV/s. The effects of the concentration of supporting electrolyte on the electrochemical characteristics of LaHCF were studied by voltammetry. LaHCF was also characterizated by scanning electron microscope (SEM), FTIR and XPS techniques.     

胞嘧啶吸附在粗糙金电极上的表面增强拉曼光谱

应用电化学伏安法和表面增强拉曼光谱(SERS)研究在-1.0 V~0 V电位区间内胞嘧啶于粗糙金电极表面的吸附行为.结果表明,在本实验的电位区间,胞嘧啶是以其N3位垂直吸附在粗糙金电极表面的.在负电位区间环呼吸振动模的强度出现极大值,与其它振动模强度相比,作者认为电磁场的增强和电荷转移均使该谱峰的拉曼信号增强.胞嘧啶的环呼吸振动频率随着电位负移而红移,这意味着它与金电极的成键作用减弱.同时也表明SERS谱可用于研究生物分子在金属电极表面的吸附行为.     

新型光化学电池高活性铂电极的研究

应用循环伏安法，在导电玻璃表面沉积微量铂，制备新型光电化学电池的高比表面高洁性对电极所获得的电极比表面最高达371m2·g-1;同时发现，该电极对的质量交换电流密度随铂沉积量的增加而减小，而相对于宏观面积的交换电流密度几乎没有变化，因此，在实验可控制的限度内，用微色的铂就可以获得高活性的对电极     

铋膜电极伏安法测定硫酸软骨素

硫酸软骨素是一种天然酸性粘多糖,属生物高分子化合物,其结构如下图所示.硫酸软骨素具有许多重要的生理活性和药理作用,如促进冠状动脉循环、降血脂、抗凝血、抗肿瘤和防止血管硬化等[1,2].     

亚微米级叉指型超微带电极阵列的加工和电化学表征

超微电极具有常规电极无法比拟的优良的电化学特性.超微电极包括单超微电极和超微电极阵列,单超微电极响应电流较小,一般仪器难以检测;而超微电极阵列除具有单超微电极的特点外,还能增加测量时的响应电流,有利于仪器检测.其中的叉指型超微带电极阵列(IDA)具有产生-收集效应,可提高检测的灵敏度,实现低浓度测量[1～4].将微电子技术和微细加工技术应用于化学和生物传感技术已引起关注,利用微细加工技术可以实现传感器的微型化、集成化和智能化;减少测量使用的样品量;使传感器的敏感元件具有确定的形状和尺寸,提高测量结果的一致性.本文用多…     

循环伏安法用于钇在钼和镍电极上的电极过程研究

使用了较为简单的数学方法,对不溶性反应产物的电极过程的循环伏安理论公式进行了推导。并将推导结果应用于LiCl—KCl—YCl_3熔盐体系,钇在钼电极上的电极过程研究,获得了很好的结果。同时还对钇在镍电极上阴极还原进行了研究,循环伏安结果表明钇和镍能够拖成金属间化合物。能谱及X射线衍射结果表明,金属间化合物的组成为Ni_2Y。     

Investigation of the electrocatalytic behavior of single-wall carbon nanotube films on an Au electrode

The voltammetric behavior of uric acid (UA) was studied with an Au electrode modified with single-wall carbon nanotubes (SWNTs). In 0.1 M HAc-NaAc buffer solution (pH 5.0), the SWNT-modified electrode shows high electrocatalytic activity toward UA oxidation. The electro-oxidation of UA is an irreversible diffusion-controlled process with a diffusion coefficient (D) of 8.85×10⁻⁶ cm² s⁻¹. The peak current increases linearly with the concentration of UA in the range of 4.0×10⁻⁶-7.0×10⁻⁴ M. The detection limit is 1.0×10⁻⁶ M. The SWNT was characterized with scanning electron microscopy (SEM). Furthermore, the SWNT-modified electrode has favorable electrocatalytic activity toward dopamine and norepinephrine. This SWNT-modified electrode can also separate the electrochemical responses of uric acid, norepinephrine and ascorbic acid.     

金箔上单层MoS2的控制生长及电催化析氢应用

金属衬底上单层MoS₂的可控批量制备是探索其微观形貌、新奇物理化学特性以及潜在应用的重要前提. 最近, 我们利用低压化学气相沉积的方法, 在多晶金箔上实现了高质量、大面积/大批量、畴区尺寸可调(从几百纳米到几十微米)单层MoS₂的可控制备; 利用低能电子显微/衍射实现了直接生长的单层MoS₂畴区取向和畴区边界的原位识别; 利用金箔上合成的纳米尺寸MoS₂作为电催化析氢反应的催化剂, 实现了高效的析氢效果(塔菲尔斜率约61 mV/dec, 交换电流密度约38.1 μA/cm²). 本文将以这些研究成果为主线, 系统地阐述金箔上单层MoS₂的可控制备和转移、畴区的原位识别以及在电催化析氢反应中的应用, 并对该领域的未来发展趋势和所面临的挑战进行简要的展望.     

Nanocrystalline‐Graphene‐Tailored Hexagonal Boron Nitride Thin Films

Unintentionally formed nanocrystalline graphene (nc‐G) can act as a useful seed for the large‐area synthesis of a hexagonal boron nitride (h‐BN) thin film with an atomically flat surface that is comparable to that of exfoliated single‐crystal h‐BN. A wafer‐scale dielectric h‐BN thin film was successfully synthesized on a bare sapphire substrate by assistance of nc‐G, which prevented structural deformations in a chemical vapor deposition process. The growth mechanism of this nc‐G‐tailored h‐BN thin film was systematically analyzed. This approach provides a novel method for preparing high‐quality two‐dimensional materials on a large surface.     

OH functionalized Multi-Walled Carbon Nanotube modified electrode as electrochemical sensor for the detection of Aceclofenac

ABSTRACT

The rapid electrochemical determination of Aceclofenac (ACF) has been employed by cyclic voltammetry (CV), differential pulse voltammetry (DPV) using developed OH-functionalised multiwalled carbon nanotube carbon paste electrode (OH-MWCNT/CPE). Modified electrode was characterised by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDAX), X-ray diffraction spectroscopy (XRD), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The ACF exhibits two oxidation peaks at +0.4 V, +0.66 V and one reduction peak at +0.3 V. The active surface area of the bare carbon paste electrode (BCPE) and modified electrode have been characterised by using K₃[Fe(CN)₆] solution containing 0.1 M KCl. In DPV mode, variation of ACF gave the limit of detection (LOD = 3s/m) 0.246 μM over the concentration range 1.0 to 190.0 μM (R² = 0.9994). The developed electrode has good stability, reproducibility and could be successfully validated for the detection of ACF in pharmaceutical samples and biological fluids.     

激光等离子体诱发SiCl4解离沉积硅膜的研究

硅是重要半导体材料之一,其薄膜广泛应用于集成电路和太阳能电池。但用普通方法制备纯硅需要很高温度,而利用激光便可在低温下进行。因此激光诱导化学气相沉积技术是改革集成电路工艺和制备太阳能电池的一种很有希望的方法。本文用SiCl_4代替通常使用的SiH_4,用TEA CO_2激光诱导SiCl_4解离气相沉积硅膜。     

Sb掺杂大尺寸ZnO纳米棒的制备及其特性研究

采用化学气相沉积法,在没有采用任何催化剂的条件下,在Si(100)衬底上成功制备出Sb掺杂大尺寸ZnO纳米棒,并对样品进行了结构和光学性质的表征。结果表明:纳米棒为结晶质量较好的六角纤锌矿结构,在能量色散谱(EDS)中观测到了Sb元素的存在。此外,在低温光致发光(PL)光谱中还观测到了与Sb掺杂相关的中性受主束缚激子发光峰(A0X)、自由电子到受主能级跃迁的发光峰(FA)、施主受主对(DAP)以及DAP的一级纵向光声子伴线(DAP-1LO),因此证实Sb元素作为受主杂质掺杂已进入ZnO晶格。     

Fabrication of new polypyrrole/silicon nitride hybrid materials for potential applications in electrochemical sensors: Synthesis and characterization

In this research, an efficient fabrication process of conducting polypyrrole (PPy)/silicon nitride (Si₃N₄) hybrid materials were developed in order to be employed as transducers in electrochemical sensors used in various environmental and biomedical applications. The fabrication process was assisted by oxidative polymerization of pyrrole (Py) monomer on the surface of Si/SiO₂/Si₃N₄ substrate in presence of FeCl₃ as oxidant. To improve the adhesion of PPy layer to Si₃N₄ surface, a pyrrole-silane (SPy) was chemically bonded through silanization process onto the Si₃N₄ surface before deposition of PPy layer. After Py polymerization, Si/SiO₂/Si₃N₄-(SPy-PPy) substrate was formed. The influence of SPy concentration and temperature of silanization process on chemical composition and surface morphology of the prepared Si/SiO₂/Si₃N₄-(SPy-PPy) substrates was studied by FTIR and SEM. In addition, the electrical properties of the prepared substrates were characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). It was found that the best silanization reaction conditions to get Si/SiO₂/Si₃N₄-(SPy-PPy) substrate with high PPy adhesion and good electrical conductivity were obtained by using SPy at low concentration (4.3 mM) at 90°C. These promising findings open the way for fabrication of new hybrid materials which can be used as transducers in miniaturized sensing devices for various environmental and biomedical applications.     

Fabrication of Au/Titania Composite Nanodot Arrays from Au‐Loaded Block Copolymer Micellar Films

Summary: A simple route to an ordered array of metal/semiconductor oxide composite nanodots is presented. Micellar monolayer films of polystyrene‐block‐poly(2‐vinyl pyridine) (PS‐b‐P2VP) loaded with HAuCl₄ in the P2VP nanodomains are used as templates. TiO₂ is generated selectively within the polar P2VP domains of PS‐b‐P2VP/HAuCl₄ films by chemical vapor deposition of TiCl₄. Subsequent removal of the organic matrix by oxygen plasma or UV light leads to an array of Au/TiO₂ composite nanoparticles on the substrate surface.

Schematic illustration of the process to fabricate an array of Au/titania composite nanodots.