ρ-Si上电沉积制备镍-磷非晶薄膜催化剂

非品态合金作为一类新型催化材料，越来越引起人们的广泛关注．Ni－P非晶态合金催化剂的催化加氢性能研究尤为活跃［‘，’］，研究结果表明其活性明显高于Ni－P晶态合金和比表面积相当的Ni粉L＼从而具有实用价值．传统的非品态合金催化剂的制备方法，如真空蒸镀、真空溅射、液相急冷及离子注入等，存在设备复杂、耗能大，难以批量生产等缺点；化学法可制备粒度均匀的催化剂＊；但给提纯带来了一定困难，而电沉积制备非晶薄膜催化剂由于具有纯度高、能耗低、制作方便等优势而倍受青睐问利用半导体做载体沉积Ni－P非晶态合金，在光电催化…     

Properties of Co-Mo coatings obtained by electrodeposition at pH 6.6

Cobalt-molybdenum coatings were prepared by electrodeposition in a sulfate-citrate bath and their morphology, structure and magnetic properties were analysed. Concentrations of 0.1 mol dm^–3 CoSO₄ and 0.005 mol dm^–3 Na₂MoO₄ at pH 6.6 led to Co-Mo deposits of 20–23% Mo that can be grown to several microns over graphite or copper substrates. At low deposition potentials or current densities, the deposits presented a close-packed hexagonal structure (hcp) that evolved to a (100)+(110) preferred orientation and acicular morphology as the deposit thickness increased. When the deposition potential or the current density was made more negative, a mixed crystalline+amorphous structure was obtained. The degree of crystallinity depended on the thickness: thin films were more amorphous than the thicker ones. Co-Mo deposits showed lower saturation magnetization (M_s) and coercivity (H_c) than the pure cobalt deposits. The crystalline+amorphous films showed the lowest H_c values (around 40 Oe).     

The mechanism of silver granular electrodeposits formation

Granules as a possible form of metal electrodeposit can be formed during deposition of metals, such deposition processes being characterized by large exchange current density values. Because of this, zero nucleation zones around growing grains are formed, permitting granular metal growth. In some cases of prolonged deposition, macro-crystalline deposits can be formed as well as granular ones, e.g. in the case of silver deposition at overpotentials lower than the critical value for dendrite growth initiation. The mechanism of granular deposit growth as a final form of metal electrocrystallization is proposed. Silver boulders were deposited on␣platinum and silver substrates. At low deposition potentials, various crystallographic forms, some of them ideal or derived from cube-octahedron-type morphology, were obtained as a result of independent grain growth inside zones of zero nucleation. In addition to cube-octahedra, twinned and multiply twinned silver particles were also observed. The nucleation density was found (1) to increase with increasing deposition overpotential, (2)␣to decrease with increasing silver concentration, and (3) to be greater on Ag than on Pt for the same deposition overpotential and dendrite precursors. Increasing overpotential leads to increase of density of twinned grains. The grain growth at greater overpotentials from more concentrated solution is less ideal, producing a granular deposit on prolonged deposition. Received: 21 April 1997 / Accepted: 18 September 1997     

Electrochemical deposition and properties of PbO2 + Co3O4 composites

Electrolysis of suspensions of Co₃O₄ particles in Pb²⁺-containing electrolytes has been used for depositing PbO₂ + Co₃O₄ composite layers on Ni rotating dise anodes. A sufficiently high angular speed of the electrode is necessary to obtain layers of homogeneous thickness and Co₃O₄ concentration. The volume fraction of Co₃O₄ particles in the deposit α reaches a limiting value of ca. 0.1 when the volume fraction of particles in suspension C exceeds 0.008. The current density j has little effect on α as long as it is in the range 1 to 20 mA cm⁻²; if j increases further, α decreases.PbO₂ + Co₃O₄ composite layers have been studied as electrode materials for the oxygen evolution reaction (mainly in NaOH solution). The overpotential and Tafel slope decrease upon increasing α. At a fixed potential, j is roughly proportional to OH⁻ concentration. The PbO₂ + Co₃O₄ electrode performance is fairly stable at 25°C but declines with time at higher temperature.     

Electrodeposition of Lead at Boron‐Doped Diamond Film Electrodes: Effect of Temperature

The electrodeposition of lead on boron‐doped diamond has been studied with a view to identifying the fundamental parameters controlling the sensitivity and lower detection limit in anodic stripping voltammetry. Chronoamperometric transients are used to explore the deposition, indicating a progressive growth mechanism confirmed by ex situ AFM images. Linear sweep ASV experiments show a threshold concentration of ca 10^?6 M below which no lead is detected; this is attributed to the need for nucleation of the solid phase on the electrode. Experiments with variable temperature show that this threshold can be usefully lowered at elevated temperatures.     

Ce4+离子对电沉积金属铬的影响

用电沉积方法从含有CrO。及少量HzSO。的电解液中制备的金属铬镀层，具有极好的反光性能及装饰性能，应用十分广泛．但长期以来，一直采用高CrO。浓度（2509·L－‘以上）、高温度（50”C以上）的工艺，加上该工艺阴极电流效率极低（10％左右）＊；环境污染、材料和能源浪费严重．近年来，在改善镇铬工艺方面的研究取得了很大的进展，其中使用各种添加剂的尝试得到了一定的成效，如使用含有卤素化合物的添加剂可提高镀铝的阴极电流效率［2－1使用含稀土化合物的添加剂可以使电解液中CrO。浓度和操作温度大大降低，而阴极电流效率却有所…     

Time-resolved electrochromic properties of MoO<Subscript>3</Subscript> thin films electrodeposited on a flexible substrate

In this paper, a MoO₃ thin film was firstly electrodeposited on flexible ITO/PET substrates. Its electrochromic properties were examined using an electrochemical workstation coupled in situ with a charge-coupled device (CCD) spectrophotometer. The film was characterized by XRD and AFM. The electrodeposited MoO₃ thin film on the ITO/PET substrate showed a large transmittance contrast between the colored and bleached states, a quick response, and good durability and reversibility. The low working potential range, –0.5 to 1.6 V (vs. Ag/AgCl), for the MoO₃/ITO/PET film prepared in this work makes it a good candidate for flexible smart windows, as well as other plastic electrochromic devices. Electronic Publication     

Utilization of electrodeposition for electrothermal atomic absorption spectrometry determination of gold

Gold was determined by electrothermal atomic absorption spectrometry after electrochemical preconcentration on the graphite ridge probe used as a working electrode and sample support. The probe surface was electrochemically modified with Pd, Re and the mixture of both. The electrolysis of gold was performed under galvanostatic control at 0.5 mA. Maximum pyrolysis temperature for the probe surface modified with Pd was 1200 °C, with Re 1300 °C. The relative standard deviation for the determination of 2 μg l^− 1 Au was not higher than 5.6% (n = 8) for 2 min electrodeposition. The sensitivity of gold determination was reproducible for 300 electrodeposition and atomization cycles. When the probe surface was modified with a mixture of Pd and Re the detection limit was 31 ng l^− 1 for 2 min electrodeposition, 3.7 ng l^− 1 for 30 min, 1.5 ng l^− 1 for 1 h and 0.4 ng l^− 1 for 4 h electrodeposition, respectively. The procedure was applied to the determination of gold in river water samples. The relative standard deviation for the determination of 2.5 ng l^− 1 Au at 4 h electrodeposition time at 0.5 mA was 7.5%.     

Growth and characterization of ZnO-SDS hybrid thin films prepared by electrochemical self-assembly method

ZnO-SDS hybrid thin films were grown on ITO glass using the potentiostatic electrodeposition route from aqueous zinc nitrate solution containing surfactant sodium dodecyle sulfanate (SDS). The electrochemical process of the hybrid films was analyzed by comparing the cyclic voltammetric curve and current-time curve with those of pure ZnO film. Results showed that the addition of a small amount of SDS could decrease the deposition current density, and inhibit the growth of ZnO crystals significantly. The hybrid films electrodeposited at −0.9 V for 30 min exhibited smooth and platelet-like morphology, with the film thickness of about 110 nm. The well-defined ZnO-SDS lamellar structures could be clearly observed, with two interlayer spaces of 35.1 and 30.9 Å, respectively. Optical analysis showed that the hybrid films had good optical quality, and exhibited the fundamental absorption edge of ZnO at 380 nm.     

Lactate Biosensor Based on Hydrotalcite‐Like Compounds: Performances and Application to Serum Samples

A lactate biosensor based on lactate oxidase supported onto a hydrotalcite, electrochemically deposited on a platinum surface, was developed for the first time. For the best electrode configuration, a linear response up to 0.8 mM, with a limit of detection of 14 μM and a sensitivity of 91 mA M^?1 cm^?2, was obtained. The influence of some interferents due to the oxidation of hydrogen peroxide (at +0.35 V vs. SCE) was also studied. By controlling carefully the experimental conditions, the determination of lactate in a commercial serum sample in the presence of interferents was successfully accomplished.