铜在HOPG上电沉积过程的现场ECSTM研究

用自制的电化学扫描隧道显微镜（ＥＣＳＴＭ）现场研究Ｃｕ在ＨＯＰＧ上的电沉积过程．结果表明Ｃｕ在ＨＯＰＧ上的电沉积为三维成核的过程．当电位较低或Ｃｕ２＋离子浓度较低时，铜在本体金属生长主要沿着台阶方向．过电位较高时，铜的成核数目增加，沉积层的晶粒有所细化．同时，非现场ＥＣＳＴＭ比较研究表明，ＳＴＭ针尖对针尖局部区域的电沉积起屏蔽作用，针尖所在区域Ｃｕ的沉积速度比其它区域明显减小     

(110)晶面全择优取向Cu镀层的制备及其条件优化

研究了添加剂聚乙二醇(PEG)、氯离子(Cl－)和电流密度对Cu的电沉积过程的影响, 着重探讨了制备(110)晶面全择优取向Cu镀层的电沉积条件及其形成机理. 循环伏安(CV)结果表明, PEG阻化Cu的电沉积, Cl－加快Cu的电沉积速率. XRD实验结果表明, PEG和Cl－在一定浓度范围有利于(110)晶面择优取向; 这两种不同特性的添加剂的协同作用可以制得(110)晶面全择优取向的较薄的Cu镀层; 所制备的全择优Cu镀层较稳定. 全择优取向Cu镀层形成的机理在于PEG和Cl－吸附过程联合起作用, 在不同晶粒的不同晶面进行选择吸附, 改变了晶面的生长速率及晶粒的快生长方向.     

Electrochemical characterization of Ni–Fe alloy codeposition under MHD control

The nickel–iron alloy electrodeposition is affected by a superimposed magnetic field. Some previous papers [Msellak et al., Magnetohydrodynamics, 39:487–493, 2003 and Msellak et al., J Magn Magn Mat, 281:295–304, 2004] have exhibited some dramatic changes in iron amount and morphology of these deposits. As it is usual for a magnetic field up to 1 T, no charge transfer effect can be expected, and the observed modifications can be explained by the magnetohydrodynamic convection that controls the iron species flux during the electrochemical reaction. By electrochemical impedance spectroscopy and physical investigations (scanning electron microscopy, X-ray diffraction, and inductively coupled plasma), the reduction process is analyzed, the characteristic parameters of the mechanism are determined, and the magnetic field effects can be quantified. Contribution to special issue on “Magnetic field effects in Electrochemistry”.     

Enhanced electrodeposition of indium hexacyanoferrate thin films through improved plating solution stability

An ordinary plating solution for indium hexacyanoferrate (InHCF) thin film deposition, mainly composed of equal concentrations of In³⁺ and [Fe(CN)₆]^3–, usually forms precipitates rapidly when either concentration is higher than few millimolar. This contributes to the plating solution's instability. Moreover, electrodeposited capacities are limited accordingly. In this work, the plating solution's stability and the electrodeposition of InHCF were greatly enhanced by adding a large amount of K⁺ and/or H⁺. It was found that a 10-mM plating solution added with 1 M HCl and 1 M KCl could be stored as fresh over a one-week period, whereas an unmodified plating solution became useless within a couple of minutes. Also, such cationic additions, especially adding H⁺, increased the electrodeposited capacity ca. 18 times at least, as compared with that obtained from the unmodified plating solution. Furthermore, related enhancing mechanisms were proposed and verified. To sum up, this study offers a means for better InHCF electrodeposition and should promote the applications of InHCF films. Electronic Publication     

Room temperature deposition of nanocrystalline cadmium peroxide thin film by electrochemical route

Nanocrystalline cadmium peroxide thin film has been electrodeposited on indium doped tin oxide glass substrate from aqueous solution at room temperature. The grain size of the nanocrystals of the film is estimated from XRD and is about 14 nm. The deposits are decomposed at 228 °C by formation of CdO, releasing plentiful heat at same time. The band-gap of the nanocrystalline CdO film made from decomposition of electrodeposited CdO₂ is around 2.4 eV.     

Potentiodynamic deposition of Prussian blue from a solution containing single component of ferricyanide and its mechanism investigation

Potentiodynamic techniques were used for the direct electrodeposition of Prussian blue nano-clusters from an acidic solution of ferricyanide. Electrochemical, EQCM, IR, AFM, and UV/vis measurements were carried out to characterize deposited nano-sized Prussian blue and to explore the formation mechanism. Results showed that ferricyanide could partially dissociate to free ferric and cyanide ions. The driving force of this dissociation is the formation of PB and the evolution of HCN. The optimal potential window for the potentiodynamic formation of PB from an acidic solution (pH 1.6) is between –0.5 V and 0.4 V. In addition, the influence of surface adsorption of CN^- ions on the formation of PB was discussed.Dedicated to Professor W. Vielstich on the occasion of his 80th birthday.     

Electropreparation of Poly(benzophenone‐4) Film Modified Electrode and Its Electrocatalytic Behavior Towards Dopamine,Ascorbic Acid and Nitrite

The oxidation of benzophenone‐4 (2‐hydroxy‐4‐methoxybenzophenone‐5‐sulfonic acid) at glassy carbon electrode gives rise to stable redox active electropolymerized film during repetitive potential cycling between 0 to 1.3 V (Ag/AgCl). Cyclic voltammogram of poly(benzophenone‐4) film shows a redox couple with well‐defined peaks. The redox response of the modified electrode was found to be depending on the pH of the contacting solution. The peak potentials were shifted to a less positive region with increasing pH and the dependence of the peak potential was found to be 51 mV/pH. The electrocatalytic behavior of poly(benzophenone‐4) film modified electrode towards oxidation of dopamine, ascorbic acid and reduction of nitrite was investigated. The oxidation of dopamine and ascorbic acid occurred at less positive potential on poly(benzophenone‐4) film compared to bare glassy carbon electrode. For dopamine, the overpotential was reduced about 180 mV. Feasibility of utilizing poly(benzophenone‐4) film coated electrode in analytical estimation of dopamine, ascorbic acid and nitrite was also demonstrated.     

Electroreduction of α-glucose on CNT/graphite electrode modified by Zn and Zn–Fe alloy

Electroreduction of -glucose to form sorbitol on Zn/CNTs and Zn alloy/CNTs electrodes has been investigated in this paper. Carbon nanotubes (CNTs) used in this paper are grown directly on graphite disks by chemical vapor deposition. Zn and Zn alloy are electrodeposited on the activated CNTs/graphite electrode by pulse galvanostatic method. The micrographs of Zn/CNTs and Zn alloy/CNTs electrodes are characterized by scanning electron microscopy. The results show that the current efficiency of -glucose reduction on CNTs electrodes is much better than that on flat Zn electrodes. The order of the current efficiency on different electrodes is as follows: Zn/CNT (0.58) Zn–Fe/CNT (0.57)>Zn–Ni/CNT (0.43) Zn/graphite (0.42)>Zn (0.40). It indicates that CNTs have good potential application in electrosynthesis. Additionally, effects of some operating parameters, such as pH, temperature and -glucose concentration, on the current efficiency of -glucose reduction are also discussed.     

Zinc-cobalt alloy: electrodeposition and characterization

Zinc-cobalt alloy electrodeposits offer enhanced corrosion protection to steel, compared to zinc deposits. A near neutral zinc-cobalt alloy sulfate bath was developed. In the absence of β-naphthol and sodium lauryl sulfate (SLS), only a light grey and non-uniform deposit was obtained. Addition of boric acid yielded a grey and uniform deposit. To obtain the grey uniform alloy deposit, the optimum bath composition was: 0.5 M ZnSO₄, 0.5 M CoSO₄, 40 g/L H₃BO₃, 0.865 g/L SLS and 0.345 g/L β-naphthol. The current efficiency for alloy deposition was 50% in the current density range 0.5–2.5 A/dm². X-ray fluorescence studies on the alloy deposit formed on steel revealed 58–75% zinc on the surface. Anodic stripping voltammetric studies were carried out on zinc-cobalt alloy films formed on glassy carbon to identify the phases formed in the alloy. Zn-Co alloy film dissolution peaks suggested the existence of β, β₁ and γ phases of the alloy. Electronic Publication     

电沉积制备钯铂电极上乙醇的电催化氧化

研究了乙醇在碱性介质（１．０ｍｏｌ·Ｌ－１ＮａＯＨ）中电沉积制备的Ｐｄ／ＧＣ、Ｐｔ／ＧＣ和Ｐｄ．Ｐｔ／ＧＣ电极上的电催化氧化．实验结果表明：由此法制备的钯铂系列合金电极对乙醇的电催化氧化表现出明显的协同效应─—乙醇在含把原子分数ｙｐｂ＝０．３３６的Ｐｄ－Ｐｔ／ＧＣ合金电极上的阳极交换电流密度是其在纯铂电极上的３０多倍．