Mechanistic study on electrochemical deposition of conjugated polymers in centrifugal fields

This work presents a detailed study of the mechanism for the electrochemical deposition of conjugated polymers on anodes in centrifugal fields. The rate of the electrochemical deposition of polyaniline was affected significantly by a centrifugal acceleration force of 315 g. However, no centrifugal effects were observed on the electrochemical deposition of poly(3,4-ethylenedioxythiophene). It was found that the degree of the centrifugal effect generated depended greatly on the size of the oligomer aggregates just before their deposition. To further confirm the influence of size on electrochemical systems under centrifugal fields, we also carried out an electrochemical redox reaction using various sizes of vinylferrocene-immobilized polystylene latex particles.     

Mini-pillar Based Multi-channel Electrochemical Platform for Studying the Multifactor Silver Electrodeposition

Here, we demonstrated a mini-pillar based multi-channel electrochemical platform that can efficiently adjust multiple electrochemical deposition parameters in the microdroplet arrays to control and predict the final structures of silver nanomaterials. Each mini-pillar is capable of anchoring microdroplet to form a separate microreactor, and the electrodes are integrated to achieve a multi-channel electrochemical electrodeposition platform. We systematically investigated the multiple deposition parameters of silver nanostructures and summarized the relevant experience of electrochemical silver deposition to guide silver nanostructure preparation. Such the mini-pillar based microdroplet platform provides an approach for further high-throughput and intelligent nanomaterial fabrication.     

Electrochemical Impedance Spectroscopic Analysis on the Electrochemical Deposition of Lead Dioxide in Acidic Medium

Electrochemical deposition of pure lead dioxides and modified lead dioxides incorporated with As(V) on a gold electrode was investigated by cyclic voltammetric, in-situ electrochemical impedance spectroscopic, and reflective UV-vis spectroelectrochemical techniques. The focus was given to analyze electrochemical impedance spectroscopic data obtained under various deposition conditions, i.e.,different deposition potentials.     

Effect of Various Deposition Techniques,Electrode Materials and Posttreatment with Tetrabutylammonium and Tetrabutylphosphonium Salts on the Electrochemical Behavior and Stability of Various Prussian Blue Modified Electrodes

The effect of various deposition techniques, electrode materials and posttreatment with tetrabutylammonium and tetrabutylphosphonium salts on the electrochemical behavior and stability of various Prussian blue (PB) modified electrodes, namely PB modified glassy carbon electrodes, silicate‐film supported PB modified glassy carbon electrodes, PB‐doped silicate glassy carbon electrodes, PB modified carbon ceramic electrodes using electrochemical deposition and PB modified carbon ceramic electrodes using chemical deposition is reported. Cyclic voltammetry and amperometric measurements of hydrogen peroxide were performed in a flow injection system while the carrier phosphate buffer (pH 7.0) with a flow rate of 0.8 mL min^?1 was propelled into the electrochemical flow through cell housing the PB modified working electrode as well as an Ag|AgCl|0.1 M KCl reference and a Pt auxiliary electrode. The results showed that the deposition procedure, electrode material and posttreatment with additional chemicals can significantly alter the stability and electrochemical behavior of the PB film. Among the studied PB modified electrodes, those based on carbon ceramic electrodes modified with a film of electropolymerized PB showed the best electrochemical stability.     

无铅镉化学镍沉积及其表征

优化无铅、无镉化学镍沉积工艺,应用扫描电子显微镜(SEM)、能量色散谱(EDS)、X射线衍射(XRD)和电化学方法表征化学镀镍层的形貌、组成、结构和电化学活性.结果表明,化学镍自催化沉积速率为22.4μm.h-1;沉积速率随溶液温度和pH值的提高而增大;比之硫酸镍,次磷酸钠对沉积速率的影响明显许多.化学镀镍层磷含量为7.8%(by mass),结构致密、晶粒细小,呈非晶态结构.在NaCl溶液中,镀层呈现良好的电化学耐蚀性.     

Characterization of the deposition of organic molecules at the surface of gold by the electrochemical reduction of aryldiazonium cations

The deposition of 4-X phenyl groups (X = NO2, COOH, N-(C2H5)2) on polycrystalline gold electrode was achieved by the electrochemical reduction of the corresponding 4-substituted phenyldiazonium tetrafluoroborate salts in anhydrous acetonitrile media. The electrochemical quartz crystal microbalance measurements evidenced a two-step deposition process: the first one is the deposition of close to a monolayer and the second one is the relatively slower growth of multilayers. In this second region, the deposition is less efficient than for the first one. The electrochemical behavior of the resulting modified gold electrode was investigated in the presence of an electroactive redox probe and these results, together with the electrochemical quartz crystal microbalance data, demonstrated significant differences in reactivity and in deposition efficiency between the diazonium salts. The characterization of the modified electrodes by cyclic voltammetry and electrochemical impedance spectroscopy, as well as X-ray photoelectron spectroscopy measurements, showed that the formation of multilayers is possible and that a significant fraction of the deposited material remained at the electrode surface, even following ultrasonic treatment. The X-ray photoelectron spectroscopy data indicate that the existence of Au-C and Au-N=N-C linkages (where C represents a carbon atom of the phenyl group) is uncertain. Nonetheless, the deposition of the aryl groups by electrochemical reduction of diazonium cations yielded a film that adheres well to the gold surface and the deposited organic film hindered gold oxides formation in acidic medium.     

Electrodeposition of Se on carbon-supported Pt nanoparticles by cyclic voltammetry

Cyclic voltammetry (CV) is a powerful and popular electrochemical technique widely used to study the surface structure of materials through the electrochemical behaviors. Herein CV is utilized to study the electrochemical deposition of selenium (Se) on carbon black-supported Pt nanostructures. We synthesized carbon-loaded platinum nanoparticles (Pt/C) by microwave method and studied the electrochemical behavior of selenium on them. Through the experiment of changing the reverse potential, the corresponding relationship between the Se deposition peak and stripping peak was clarified and the deposition and stripping process of Se was proposed. Meanwhile, we synthesized cubic and octahedral nanocrystals of Pt, and used CV to study the Se deposition on these nanosctructures supported by carbon. It was found that the relative intensity of UPD peaks on Pt is different, as Pt_cube@C is dominated by (100) and Pt_oct@C electrode is dominated by (111) while Pt@C falls in between.

     

Flexible metal film with micro- and nanopatterns transferred by electrochemical deposition

A new method for patterning microstructure on metal film by electrochemical deposition is provided. The metal film with micropattern can be peeled off after the deposition by inter-medium layer of resistant molecules such as triglyceride. We can use the technology of electrochemical deposition to make the metal film possess different functions such as soft and bendable properties. We also give an example to get the protein pattern transferred on the metal film. So, this method can also provide a way for the fabrication of protein pattern on the chip.     

Electrodeposition and Characterization of Polyaniline Film

Polyaniline film was prepared by electrochemical method in an acidic solution of aniline. The micromorphology of the polyaniline film was transformed to three-dimensional network structure instead of little particles while the deposition time was extended. The peak wavelength of the photoluminescence spectrum was 491 nm. The luminous intensity increased with the extension of deposition time, and so did the electrochemical activity.     

Scanning electron microscopy in the analysis of the activity of graphite electrodes

Copper deposition patterns on graphite electrodes were analyzed by scanning electron microscopy. The deposition patterns correlate very well with the electrochemical activity of different graphites. The results indicate that treatment of graphite by electroactivation, laser irradiation of polishing on 600-grit silicon carbide paper produces active sites on the surface. The density of the sites directly reflects the electrochemical reactivity of the surface.     

Mechanism of film growth of tellurium by electrochemical deposition in the presence and absence of cadmium ions

The growth morphology and the kinetics of a thin film of Te on Au during electrochemical deposition at -62 mV (vs Ag/AgCl/3 M NaCl) have been studied. The deposition conditions are similar to those used previously by us to grow nanowires inside Au nanotubes by electrochemical deposition in the presence of Cd ions (Cd(2+)). By using electrochemical deposition on a planar Au electrode, we explored the growth of the Te film for two conditions: in the presence of Cd(2+) (0.1 mM TeO(2) + 1 mM CdSO(4) + 50 mM H(2)SO(4) solution) and in the absence of Cd(2+) (0.1 mM TeO(2) + 50 mM H(2)SO(4) solution). We used several surface investigation techniques to study the growth such as: in situ electrochemical atomic force microscopy (EC-AFM), in situ electrochemical surface plasmon resonance (EC-SPR), electrochemical methods, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). In the presence of Cd(2+), in situ electrochemical atomic microscopy showed that Cd(2+) acted as a mediator at the early deposition stage and caused smoothing of the Te deposit obtained. In the absence of Cd(2+), Te had an island growth. The electrochemical surface plasmon resonance showed that the deposit was characterized by a slower deposition rate in the presence of Cd(2+) than in the absence of Cd(2+). Additionally, the thickness of the film was evaluated using EC-AFM measurements, electrochemical stripping analysis, and EC-SPR. The results obtained from all three measurements agree well with the Te film obtained in the presence of Cd(2+), where a continuous and uniform film was formed. In the presence of Cd(2+), a Te film with a thickness of 1.04 nm and atomically flat surface was deposited on an ultraflat Au surface. The XPS spectrum showed no significant amount of Cd in the deposit, indicating that the Cd ion acted as a mediator and not as a co-deposition element.     

Cadmium selenide microspheres as an electrochemical supercapacitor

This paper reports the synthesis of cadmium selenide electrodes by simple and cost effective chemical bath deposition method for the electrochemical supercapacitors. In order to study the effect of deposition time onto the morphological and electrochemical performance of CdSe electrodes, the reaction time was varied from 2 h to 10 h. As the reaction time goes on increasing the voide-less uniform growth of the thin films with increased size and density of CdSe microspheres is observed from field emission microscopy study. The supercapacitive behavior of the prepared electrodes were analysed with the help of electrochemical impedance, cyclic voltammetry and charge/discharge measurements. The areal capacitance is found to increase from 0.30 mFcm^?2 to 1.285 mFcm^?2 with respect to the deposition time, this indicates the positive effect towards the electrochemical performance.     

Electrocatalytic oxidation of glucose in a neutral medium on an electrode modified by carboxylated multi-walled carbon nanotubes and by silver and palladium

Russian Chemical Bulletin - Drop deposition of a carboxylated multi-walled carbon nanotube suspension and layer-by-layer electrochemical deposition of silver and palladium were used to modify...     

电化学沉积CdSe纳晶薄膜的性能及沉积机理

电化学沉积是半导体薄膜制备的一种简便方法,常用于Ⅱ-族化合物半导体薄膜的制备.通过电沉积条件的适当改变可成功地在导电衬底上制备半导体纳晶薄膜^[1].CdSe薄膜作为一种透光性好、导电性好的半导体材料,可进行光学性能和光电性能方面的研究,而半导体纳晶多孔电极的光电化学特性与体材料之间有很大不同.本文采用电化学沉积法制备了CdSe纳晶薄膜并研究了其性能,通过扫描隧道显微镜(STM)形貌分形分析进一步研究其沉积机理.     

Comparative study of nucleation and growth mechanism of cobalt electrodeposited on ITO substrate in nitrate and chloride electrolytes

Journal of Solid State Electrochemistry - A comparative study of the electrochemical deposition of cobalt on tin-doped indium oxide (ITO) substrate was carried out using electrochemical techniques...     

Electrochemical Processing of Reaction-bonded Ceramic Composite Coatings

Ceramic matrix composite coatings are currently of much interest for application in high-temperature and highly corrosive environments. Formation of ceramic coatings by electrochemical processing is a relatively new mean^[1-2]. It presents several advantages over alternative coating techniques, the thickness and morphology of the deposit can be controlled by the electrochemical parameters, relatively uniform deposits are obtainable on complex shapes, the deposition rate is higher than that using most other methods and the equipment required is of low cost Recently we developed a novel fabrication technique for the production of ceramic/ceramic and ceramic/metal composite coatings by electrochemical processing^[3]. The technique combined two electrochemical deposition methods, electrophoretic deposition (EPD) and electrolytic deposition (ELD), which can produce uniform composite layers of closely controlled thickness on both metallic and ceramic substrates at ambient temperature with inexpensive equipment. However, the main problem associated with electrochemical processing is the difficulty in sintering of the coatings. First, high temperature is required for sintering of the coatings. Secondly, the volume shrinkage of the coatings during sintering leads to the formation of cracks in coatings bonded to metal substrates. So a reaction forming technique, reaction bonding process, also has been developed to produce near net-shape ceramic coatings, which overcome problems caused by the shrinkage of ceramics during sintering.     

Localized Deposition of Chitosan as Matrix for Enzyme Immobilization

A local electrodeposition method was developed for chitosan by exploiting a pH gradient between a macroscopic electrode (the support) and a much smaller counter electrode. The deposition was confined either by using the direct mode of scanning electrochemical microscopy (SECM) or by performing the deposition in channels of a microfluidic network. The roughness was characterized by noncontact scanning force microscopy. The availability of amino groups at the surface of the microstructures was visualized after labeling by confocal laser scanning microscopy. The enzyme glucose oxidase could be entrapped during the electrochemical deposition and showed activity as seen by SECM images.     

Electrochemical studies on Zn deposition and dissolution in sulphate electrolyte

The electrochemical deposition and dissolution of Zn on Pt electrode in sulphate electrolyte was investigated by electrochemical methods in an attempt to contribute to the better understanding of the more complex Zn–Cr alloy electrodeposition process. A decrease of the Zn electrolyte pH (from 5.4 to 1.0) so as to minimise/avoid the formation of hydroxo-products of Cr in the electrolyte for deposition of alloy coatings decreases the current efficiency for the Zn reaction, but the rate of the cathode reaction increases significantly due to intense hydrogen evolution. The results of the investigations in Zn electrolytes with pH 1.0–1.6 indicate that Zn bulk deposition is preceded by hydrogen evolution, stepwise Zn underpotential deposition (UPD) and formation of a Zn–Pt alloy. Hydrogen evolution from H₂O starts in the potential range of Zn bulk deposition. Data obtained from the electrochemical quartz crystal microbalance (EQCM) measurements support the assumption that electrochemical deposition of Zn proceeds at potentials more positive than the reversible potential of Zn. Anodic potentiodynamic curves for galvanostatically and potentiostatically deposited Zn layers provide indirect evidence about the dissolution of Zn from an alloy with the Pt substrate. The presumed potential of co-deposition of Cr (−1.9 V vs. Hg/Hg₂SO₄) is reached at a current density of about 300 mA cm⁻².     

结合化学组装和电沉积的SERS基底的制备方法

采用一种结合化学组装和电化学沉积制备均匀而且具有强SERS基底的方法, 研究了沉积电位对组装在ITO表面的金纳米粒子形貌的影响, 发现在-0.04 V下沉积5 min可以得到形貌均匀的纳米粒子. 利用现场电化学紫外-可见吸收光谱来监控电化学沉积过程, 发现沉积一定时间后, 紫外-可见吸收谱在600~700 nm区间出现新峰, 表明粒子间发生了有效的电磁场耦合. 对制备的基底进行拉曼成像, 结果表明, 基底的均匀性很好, 最强点与最弱点的d信号差小于20%, 符合商品化基底的要求.     

电沉积法制备固态染料敏化太阳能电池

本文采用一步电化学沉积的方法在导电玻璃上先后沉积了ZnO/染料复合薄膜以及CuSCN薄层,实现仅以电沉积法制备结构为ZnO/染料/CuSCN的固态染料敏化太阳能电池,电池的光电转换效率达到0.1%.在电沉积CuSCN前,脱附电沉积制备的ZnO/染料复合薄膜中的染料以形成多孔ZnO薄膜,然后通过染料再吸附得到染料敏化ZnO纳晶多孔薄膜.在电沉积过程中,ZnO和CuSCN的晶体尺寸、晶体取向和膜层形貌都可以进行比较精准的控制.探讨了影响沉积薄膜形貌和光电转换效率的因素,如旋转圆盘电极的旋转速度、电沉积温度以及染料敏化剂的选择.本文报道的低温电沉积制备全固态太阳能电池的方法为制备柔性染料敏化太阳能电池提供了一种新的思路.