铅在铜上电沉积的原位椭圆偏振法

采用循环伏安法(CV)和原位椭圆偏振法(SE)研究铅在铜电极上的电沉积行为。 原位椭圆偏振参数Ψ和Δ值的变化率在CV图峰电位处同时出现极值。 通过建立单层膜模型描述“电极-溶液”界面的结构并对椭圆偏振光谱数据进行拟合得到铅沉积层厚度随电位的变化规律。 拟合结果显示,铅在铜电极上的电沉积有3个不同的沉积速率,-0.20～-0.35 V之间沉积速率为0.003 nm/mV,-0.35～-0.48 V之间沉积速率为0.025 nm/mV,-0.48～-0.60 V之间沉积速率为0.116 nm/mV,由此表明铅的电沉积分为3个不同阶段：欠电位沉积阶段、欠电位沉积向本体沉积的过渡阶段和本体沉积阶段。     

从2AlCl3/Et3NHCl离子液体中电沉积制备Ni 和Ni-Al 合金

在含Ni2+的2AlCl3/Et3NHCl离子液体中的铜电极上通过恒电位电沉积制备出金属Ni和Ni-Al合金.采用循环伏安和计时电流方法,揭示铜电极上沉积金属Ni的成核机理,研究了电沉积Ni-Al合金的机理,以及恒电位沉积Ni-Al合金工艺条件对沉积Ni-Al合金表面形貌和电流效率的影响.结果表明:在铜电极上电沉积金属Ni的成核机理为受扩散控制的三维瞬时成核过程.在电量≥3.0 C时,电沉积Ni-Al合金的组成基本不再变化.Ni-Al合金的电沉积机理为,Ni的电沉积受扩散控制,同时进行Al的欠电位沉积,在Ni-Al合金电沉积过程中某些Ni-Al合金相的沉积可能受动力学限制而使Ni-Al合金的组成偏离热力学预测结果.在电沉积Ni-Al合金的沉积电流小且平稳,电沉积速率慢条件下,Ni-Al合金表面形貌致密均一,反之就会出现瘤节.电沉积Ni-Al合金的电流效率＞90％.电沉积物的组成接近于Ni3Al合金.     

锌在金电极上的欠电位沉积

采用循环伏安法和计时电流法,研究了强碱溶液中锌在金电极上的欠电位沉积。 通过改变锌离子浓度和扫描速率等实验参数,在约-0.935 V（vs.SCE）开始出现锌的欠电位沉积,并且金属离子浓度的变化可能会影响到欠电位沉积过程的动力学机制;计时电流实验证实,锌欠电位沉积于金衬底上遵循的是受掺入吸附原子控制的二维瞬时成核和生长机制;且OH-离子的吸附对锌欠电位沉积具有重要的影响。     

离子液体中钴的电沉积行为

在含有氯化钴的室温离子液体氯化1-甲基-3-乙基咪唑(EMIC)和乙二醇(EG)体系中研究了金属钴的电沉积. 循环伏安法测试表明, 在EMIC-CoCl2熔盐中, 乙二醇的加入促进了EMIC的解离, 从而使氧化还原电流增大, 在EMIC-CoCl2-EG体系中钴的电沉积是受扩散控制的非可逆电极过程, 在该电解液体系中, Co(II)在Pt电极上的传递系数α为0.30, 扩散系数D0为4.16×10^-6 cm·s^-1; 计时电流法研究表明, 钴在铂电极上的电结晶过程符合三维连续成核的生长机理; 场发射扫描电子显微镜(FE-SEM)观察镀层的微观形貌显示, 金属钴的结晶细小. XRD分析证实, 镀层为纯钴, 沉积的钴是晶态和微晶态的混合物, 并且晶粒尺寸为纳米级.     

电位活化现象与金属电沉积初始过程的研究

进行了恒电流电位-时间曲线和循环伏安曲线的测定，显示了铁电极进行氰化物镀铜时，镀层沉积前铁表面的电位活化过程. 对铁电极上焦磷酸盐镀铜的初始过程研究表明，由于铜的析出电位较正，铜是在未活化的电极表面上沉积的，因此镀层的结合强度很差.采用氩离子溅射和X射线光电子能谱相结合的方法，检测焦磷酸盐镀铜层和铁基体界面区含氧量的变化，证明了氧化层的存在. 通过添加辅助络合剂和控制起始电流密度的方法，可以增强无氰电镀时阴极的极化. 当铜的析出电位负于铁基体的活化电位时，可显示出铁表面的电位活化过程，定量测量镀层的结合强度也与氰化物电镀相近.     

甲醇在欠电位沉积Ru修饰Pt电极上的催化氧化

采用欠电位沉积(upd)方法在Pt 表面沉积亚单层的Ru制备出upd-Ru/Pt 电极. 通过欠电位沉积前后电极在0.5 mol·L-1 H2SO4溶液中循环伏安图-152 - 128 mV(vs Ag/AgCl)电位范围内对氢区的数值积分确定Pt表面Ru 的覆盖度. 用电化学方法测试了甲醇在upd-Ru/Pt电极上的催化氧化, 并讨论分析了欠电位沉积电位和Ru的表面覆盖度对甲醇氧化的影响. 结果表明, Ru能够欠电位沉积到Pt表面. Pt表面欠电位沉积少量的Ru 即能大大促进甲醇的氧化.只要控制upd-Ru的沉积量, upd-Ru原子就能大大促进甲醇氧化而与沉积电位无关. Ru原子对甲醇氧化的促进作用与Ru和Pt是否形成合金无关, 而取决于Ru 在Pt表面的百分含量.     

锗钨酸盐的电化学性能及GeW11Co/P-oPD/GC电极对过氧化氢的电催化还原

研究了杂多酸-钴取代三聚Keggin结构锗钨酸盐（[Co（H2O）3（α-GeW11CoO38）3]10-）的电化学性能.实验表明,在玻碳（GC）电极上,锗钨酸盐循环伏安曲线呈现2对可逆的氧化还原峰,峰电位差分别为31 mV和35 mV,各对应于2电子4质子和2电子3质子电极反应,其过程受表面吸附控制.经过电聚合将Ge...     

电还原氧化石墨烯-铁氰化钴修饰电极对肼的测定

本文提出了一种新的水合肼的测定方法。利用静电作用,在氧化石墨烯(GO)表面吸附一层均匀分散的Co2+形成GO-Co2+复合物,通过恒电位法电还原复合物中的GO,再利用循环伏安法将吸附的Co2+转化为铁氰化钴(CoHCF),制得电还原的氧化石墨烯-铁氰化钴修饰玻碳电极(ERGO-CoHCF/GCE)。采用扫描电子显微镜(SEM)对修饰电极表面进行了表征。研究了水合肼在该修饰电极上的电化学行为及在不同电极上的电流响应。结果表明:ERGO-CoHCF/GCE对肼具有很好的电催化氧化作用,其浓度与氧化峰电流呈良好的线性关系。     

镍钨硼合金电沉积机理及镀层微晶尺寸

应用循环伏安、恒电位阶跃和X射线衍射 (XRD)等方法研究了Ni_W_B合金电沉积特点和镀层微晶尺寸 .结果表明 ,在以柠檬酸铵为络合剂的溶液中 ,Ni_W_B合金沉积层较Ni_W合金有较低的电化学活性 .电位阶跃i～t曲线分析表明 ,在玻碳电极上Ni_W_B合金电结晶过程遵循扩散控制瞬时成核三维成长模式 ,且随过电位的增加 ,电极表面晶核数增多 .XRD测试结果表明 ,随沉积电流密度提高 ,合金镀层微晶尺寸逐渐增大 ,说明电流密度提高将更加有利于Ni_W_B合金电结晶过程中的晶核生长 .     

Pt(S)[n(100)×(110)]表面Cu欠电位沉积(英文)

本文研究了Cu在Pt(100)台阶面和(110)单原子台阶的欠电位沉积.发现若不考虑阴离子吸附,初始阶段Cu在台阶面和台阶处的电沉积同时进行.在电沉积满单层的伏安曲线上,可以观察到若干峰.通过对峰电荷与台阶密度关系的分析,可认为这些峰分别对应于不同的沉积位点.较正电位的峰对应于Cu在台阶面上的电沉积,而在台阶处Cu的电沉积则因溶液中的阴离子而具有不同的伏安性质.此外,还发现Pt电极表面的Cu沉积电荷转移数接近2e,且沉积初始阶段阴离子覆盖度不变.     

Effect of Anionic Electrolytes and Precursor Concentrations on the Electrodeposited Pt Structures

Electrodeposition of functional metal surfaces has received great attention because of their useful applications. Recently, interesting electrodeposition behavior of Pt at −0.8 V (vs. Ag/AgCl) was reported, where underpotential deposited H (H_upd) layers played a unique role in the electrodeposition. Here, we report the effect of anionic electrolytes and precursor concentrations on the electrochemical deposition behavior of Pt. Depending on these two experimental parameters, two distinct Pt structures, monolayer Pt films and Pt spheres, were electrodeposited at −0.8 V. In addition to the underpotential deposited H (H_upd) layers formed at −0.8 V, the adsorption of Cl⁻ also plays a significant role in determining the electrodeposited Pt structures. When the PtCl₄²⁻ concentration was low and the Cl⁻ concentration was high enough for the adsorption of PtCl₄²⁻ to be blocked by the H_upd and Cl⁻ layers, monolayer Pt films were electrodeposited. Otherwise, further electrodeposition of Pt spheres over the monolayer Pt films occurred. The effect of other halide ion adsorption and the controlled growth of Pt spheres during the Pt electrodeposition were also investigated. The electrochemical deposition behavior of Pt demonstrated in this work provides insight into the fabrication of functional Pt surfaces.     

Characterization of electrodeposited Co + Ni alloys by application of the ALSV technique Professor Aleksandar Despic to commemorate his 70th birthday

Anomalous codeposition of Co and Ni onto a gold RDE was investigated in a solution containing simple sulfate salts with the addition of sodium citrate. It was shown that the dependence of the percentage of Co in the deposit on the percentage of Co in the bath follows the shape found in the literature, with the percentage of Co in the deposit being slightly higher than in electrolytes containing pure simple salts. Alloy layers of different composition, electrodeposited at constant charge Q_dep = 1 C cm⁻² (thickness 0.34 μm) were submitted to anodic dissolution at a sweep rate of 1 mV s⁻¹ (ALSV technique) in a solution of 1 M NaCl, pH 2. All samples were found to dissolve through a single anodic peak, indicating that both constituents of the alloy dissolve simultaneously. Alloys with higher Ni content (above 40at.%) were found to dissolve at potentials more positive than the potential of pure Ni dissolution as a consequence of the Gibbs energy change of formation of electrodeposited solid solution type Co + Ni alloys. The composition of electrodeposited alloys was determined by the atomic absorption technique. An attempt was made to obtain a correlation between the peak potentials of anodic dissolution of alloy samples and the composition of alloys, to determine the composition of the alloy from the peak potential of its dissolution. It is found that such a correlation can be used only for strictly defined conditions of alloy deposition and dissolution, caused by the contribution of the Gibbs energy change of formation of electrodeposited alloys. Also, the presence of a CoNi₃ ordered structure in the system is not detected as a separate ALSV peak, but its existence could be the cause of the shape of the Gibbs energy change with composition of the alloy for alloys electrodeposited at low current density.     

Electrodeposition of Zn–Ni–P compositionally modulated multilayer coatings: An attempt to deposit Ni–P and Zn–Ni alloys from a single bath

The effects of bath composition and deposition variables on the electrodeposition of Zn–Ni–P alloys were studied in order to develop a single bath for deposition of Ni–P/Zn–Ni compositionally modulated multilayer coatings (CMMCs). The basis for development of the bath was a large increase in the Ni deposition rate compared to that of Zn at low deposition overpotentials combined with the impossibility of codeposition of Zn with P. EDS analysis demonstrated that the deposits obtained from the Zn–Ni–P bath at low overpotentials were practically all Ni–P, while the alloy deposited at high overpotentials was mainly Zn–Ni with around 3.2 wt% P content.     

高序石墨电极上单分散纳米铜粒子的电结

Mechanism of copper electrocrystallization on highly oriented pyrolytic graphite electrode from a solution of 1 mmol/L CuSO4 and 1.0 mol/L H2SO4 has been studied using cyclic voltammogram and chronoamperometry. The results show that in copper electrodeposition the charge-transfer step is fast and the rate of growth is controlled by the rate of mass transfer of copper ions to the growing centers. Reduction of Cu(Ⅱ) ions did not undergo underpotential deposition. The initial deposition kinetics of Cu electrocrystallization corresponds to a model including progressive nucleation and diffusion controlled growth. Copper nanocrystals with size of 75.6 nm and relative standard deviation of 9% can be obtained by modulation potential electrodeposition.     

Electrodeposition of silicon from three different ionic liquids: possible influence of the anion on the deposition process

The electrodeposition of silicon was investigated from three different ionic liquids with the cation 1-butyl-1-methylpyrrolidinium ([Py_1,4]⁺) and three different anions, namely, trifluoromethylsulfonate (TfO^?), bis(trifluoromethylsulfonyl)amide (TFSA^?) and tris(pentafluoroethyl)-trifluorophosphate (FAP^?) at room temperature and at 100 °C, respectively. The electrodeposition was performed on gold and on copper substrates. Cyclic voltammetry was used to evaluate the possible influence of anions on the deposition process. In situ STM studies were also carried out to examine the interfacial behaviour of the SiCl₄/[Py_1,4]TFSA and SiCl₄/[Py_1,4]FAP on Au(111) at room temperature. In situ STM measurements revealed that an underpotential deposition of Si in [Py_1,4]FAP occurred on Au (111) at ~ -0.5 V (vs. Fc/Fc⁺). In comparison, only adsorption of ionic liquid and gold surface reconstruction was found to occur in the potential regime between -0.3 and ?1.8 V (vs. Fc/Fc⁺), respectively, in the case of [Py_1,4]TFSA. In situ STM investigations reveal an effect of the anion on the interfacial processes. In situ I/U tunnelling spectroscopy shows that the band gap of the electrodeposits is ~1.1 eV, indicating that semiconducting silicon has been electrodeposited. Potentiostatic electrolysis was performed to deposit Si from the employed electrolytes at room temperature and at 100 °C. The deposits were characterised using scanning electron microscopy and X-ray diffraction. Thin films of Si could be obtained from the employed ionic liquids and the quality of the deposits was significantly improved at 100 °C.     

Switching transition states with changing electrode potential: Zn(II)/Zn electrodeposition on glassy carbon in the N-butyl-N-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ionic liquid

The mechanisms for the electrodeposition and stripping of Zn²⁺|Zn in the N-butyl-N-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ionic liquid are investigated via cyclic voltammetry. Analysis showed that the deposition of Zn onto a bulk Zn surface occurred via a two-electron process, with the first electron transfer being rate determining. The electrodissolution was found to occur via a potential-dependent mechanism with the first electron transfer being rate determining near the formal potential, while an intermediate chemical step became rate determining at more positive potentials.     

Electrochemical deposition of germanium sulfide from room-temperature ionic liquids and subsequent Ag doping in an aqueous solution

A facile room-temperature electrochemical deposition process for germanium sulfide (GeS(x)) has been developed with the use of an ionic liquid as an electrolyte. The electrodeposition mechanism follows the induced codeposition of Ge and S precursors in ionic liquids generating GeS(x) films. The electrodeposited GeS(x) films were characterized by scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) and Raman and X-ray photoelectron spectroscopy (XPS). An aqueous-based Ag doping method was used to dope electrochemically grown GeS(x) films with controlled doping compared to the conventional process, which can be used in next-generation solid-state memory devices.     

New insights on the Cd UPD on Au(111)

The Cd underpotential deposition (UPD) process on Au(111) was analyzed by means of combined electrochemical measurements and in situ scanning tunneling microscopy (STM). In the underpotential range 300?ΔE (mV) ?400, 2D Cd islands are formed on the fcc regions of the Au(111)‐(√3 × 22) reconstructed surface without lifting the reconstruction. At lower underpotentials, the 2D Cd islands grow and, simultaneously, new 2D islands nucleate and coalesce with the previous ones forming a complete condensed Cd monolayer (ML). STM images and long time polarization experiments performed at ΔE = 70 mV demonstrate the formation of an Au? Cd surface alloy. At ΔE = 10 mV, the formation of the complete Cd ML is accompanied by a significant Au? Cd surface alloying and the kinetic results reveal two different solid‐state diffusion processes. The first one, with a diffusion coefficient D₁ = 4 × 10^?17 cm² s^?1, could be ascribed to the mutual diffusion of Au and Cd atoms through a highly distorted (vacancy‐rich) Au? Cd alloy layer. The second and faster diffusion process (D₂ = 7 × 10^?16 cm² s^?1) is associated with the appearance of an additional peak in the anodic stripping curves and could be attributed to the formation of another Cd_zAu_x alloy phase. Copyright © 2008 John Wiley & Sons, Ltd.     

Electrical-Conductive/Insulating Bi-Functional Layers for Stable Zn Metal Anode

Zinc-ion batteries are regarded as an extremely promising candidate for large-scale energy storage equipment due to the inexpensive ingredients and high safety. However, dendrite growth and side reactions occur in the Zn anode, which lead to exceedingly low coulombic efficiency (CE) and poor cycling stability. In this work, we propose a strategy of a conductive/insulating bi-functional coating layer (CIBL) for stable Zn metal anodes. Porous Ag nanowires (NWs) coating as a conductive layer effectively reduces the nuclear barrier and contains Zn²⁺ deposition in a certain space. Polyimide (PI) coatings as insulating layer implement a shunting effect on Zn²⁺, which could reduce the differential concentration on the Zn surface and induce uniform deposition of Zn²⁺. Therefore, the CIBL−Zn//CIBL−Zn battery achieves stable plating/stripping of over 1300 h at 1 mA cm⁻². The CE of CIBL−Zn//CIBL−Zn battery maintains at 99.2 % even after 1000 cycles. Moreover, the CIBL−Zn//V₂O₅ battery exhibits a capacity of nearly 289.2 mA h g⁻¹ at 5 A g⁻¹ after 3000 cycles and no sign of capacity degradation is found, which further demonstrate the feasibility of this strategy in practical application.     

Zn–HA–TiO2 nanocomposite coatings electrodeposited on a NiTi shape memory alloy

In this work, zinc–hydroxyapatite (Zn–HA) and zinc–hydroxyapatite–titania (Zn–HA–TiO₂) nanocomposite coatings were electrodeposited onto a NiTi shape memory alloy, using a chloride zinc plating bath. The structure of the composite coatings was characterized by X‐ray diffraction, scanning electron microscopy and high‐resolution transmission electron microscopy. According to the results, the Zn–HA–TiO₂ coating exhibited a plate‐like surface morphology, where the addition of the nanoparticles caused to an increase in roughness. It was also found that due to applying a proper stirring procedure during co‐deposition, a homogenous dispersion of the nanoparticles in the coatings was achieved. Also, the addition of the TiO₂ nanoparticles to the Zn–HA–TiO₂ coating enhanced the microhardness and wear resistance. Copyright © 2014 John Wiley & Sons, Ltd.