非晶态镍磷合金电沉积机理的研究

通过镍磷合金电沉积阴极极化曲线，循环估安曲线，旋转圆盘电极极化曲线以及电位阶跃电流－时间曲线的测量和分析，并根据数学，物理，物理化学，流体力学和电化学动力学等原理，在假设的基础出镍磷合金电沉积的理论模型，镍磷合金电沉积为液相扩散和电化学放电混合控制，与实验结果相一致。     

甲醛在nano-Pt/GC电极上的电催化氧化研究

应用循环伏安法制备了nano-Pt/GC电极,并用SEM和电极在H2SO4中的循环伏安曲线对其进行了表征。结果表明,该方法制备的电极表面铂粒子分布较为均匀,粒径大小约为140nm,电极具有较大比表面积。电化学实验表明,该电极对甲醛电氧化的催化活性明显好于铂片电极。修饰电极的催化活性与铂粒子的沉积条件有关,铂微粒在电极表面的最佳沉积条件为循环次数100次和沉积速度5mV/s。     

稳态下玻璃电熔炉中锡电极的温度分布

根据STANNEX电极的热导率曲线,以平壁导热为模型,建立了锡电极中心轴向温度分布的简化数学模型,根据锡电极使用的实际情况建立实验炉,测试了锡电极在稳态下的边界温度以及锡电极中心在稳态下的实际温度分布,根据实验测得的边界条件对锡电极的温度分布作推导,得出了锡电极的轴向温度分布,对电极导电的牵引(如采用哪种联结材料,选择合适的连接方式)具有指导意义,同时对玻璃电熔炉的散热与功率配置以及电极使用过程中的冷却提供了参考,根据实际温度情况采取相应的冷却措施,从而可以延长电极的使用寿命.     

锡阴电极的制备及析氢性能的研究

为了提高锡电结晶过电位,改善锡镀层表面形貌和制备较好的镀锡电极,通过电镀技术在室温条件下制备了不同电镀液条件下的锡镀层,运用线性伏安法、交流阻抗法和电势阶跃法等电化学方法和SEM技术研究了酸性镀锡体系中明胶对锡沉积的影响。阴极极化曲线和交流阻抗曲线表明,明胶能增大锡沉积反应的电荷传递内阻,提高锡电沉积过电位,延缓锡电沉积反应。电势阶跃表明,锡的电结晶过程遵循扩散控制瞬时成核和三维生长方式的结晶机理。SEM分析结果表明,添加明胶能使锡镀层光滑致密、晶粒细小。电极的极化曲线表明,镀锡电极能提高析氢电位,其中添加明胶所得的锡电极的析氢效果最好。     

钛基锡锑中间层上二氧化铅电沉积过程的研究

运用电化学手段研究了钛基锡锑中间层上二氧化铅的阳极电沉积过程.循环伏安曲线表明,二氧化铅的电沉积经历了晶核形成过程,通过恒电位阶跃暂态曲线可知,二氧化铅在Ti/SnO2-Sb2O5电极上的电沉积初始过程遵循扩散控制的瞬时成核和三维长大方式,且随着过电位的增加,电极表面上晶核数增多.     

N,N-二甲基甲酰胺体系电沉积铋−碲热电薄膜

在N,N-二甲基甲酰胺(DMF)有机溶剂中先通过阴极极化曲线和循环伏安曲线测试研究了Bi(III)、Te(IV)离子及二者混合时在金电极上电沉积的电化学行为.再在不同电位下电沉积制备了Bi-Te热电薄膜,研究了沉积电位对Bi-Te薄膜性能的影响.结果表明,Bi(III)、Te(IV)及Bi-Te在金电极上的电沉积均属于...     

温度对金属镍电沉积中枝晶分形生长的影响

将分形几何与电化学原理相结合,通过改进的有限扩散凝聚模型(diffusion-limited aggregation,DLA),采用基于Microsoft Visual C 6.0编程,模拟温度对点电极电沉积结果的影响.以环形金属镍为阳极,石墨为阴极,用自行设计的试验设备研究了不同温度时金属镍二维电沉积生长的行为特性,并与模拟结果进行比较.结果表明:在保持电压恒定的条件下,温度对点电极电沉积的影响与采用DLA模型模拟所得的结果具有相似性,表明利用DLA模型模拟的结果对枝晶电沉积的试验研究具有很好的指导意义.     

Ti/SnO_2+Sb_2O_4+GF/PbO_X电极的制备及电催化性能研究

采用热分解和电沉积相结合方法制备了Ti/SnO2＋Sb2O4＋GF/PbOX电极,采用三电极体系测定了上述电极在不同溶液中的循环伏安曲线,同时利用循环伏安曲线求得了电极表面的分形维数、活化能和动力学参数等。结果表明该电极电催化性能优于传统电极,是一种优良的电催化剂。     

填充床鼓泡电化学反应器行为特性──Ⅱ.丙烯阳极直接氧化强非线性模型的逆算符方法求解

利用逆算符方法（ＩＯＭ）对所建立的填充床鼓泡电化学反应器的强非线性微分方程组进行了近似解析求解．利用该近似解析解，一方面可以直观地分析有关参数对反应器行为特性的影响；另一方面，与测量电极反应伏安特性曲线的实验方法相结合，可较方便地回归出非线性模型的参数值，并对模拟结果加以验证．     

电场分布对R123沸腾换热的影响

采用6种不同电极布置方式,进行了不同电势和热流密度下的R123池沸腾换热的试验研究。通过数值分析,计算了不同电极布置下换热面上的电场强度及分布。不同的电极布置,会导致换热面上电场强度和电场均匀性两方面的变化。结合试验和电场分布的计算结果,分析了电场均匀性、电场强度、热流密度与沸腾换热效果之间的关系。结果表明,在低热流密度下,电场分布对沸腾换热影响较大;而在高热流密度下,影响较小。电水动力学（EHD）强化换热效果是电场强度和电场均匀性综合作用的结果。     

POROUS ELECTRODE THEORY ANALYSIS OF A VARIABLE-DEPTH, FLOW-BY POROUS ELECTRODE

A comparison has been made between a variable-depth and constant-depth, flow-by porous electrode in which a single metal ion deposition occurs in parallel with proton reduction. Porous-electrode theory was applied to calculate the reactor's performance under limiting-current and below limiting-current conditions. The thickness profile of the variable-depth electrode was calculated—as first suggested by Kreysa—by constraining the solution phase potential drop across the electrode to remain constant and independent of streamwise position. For each reactor configuration, identical electrolyte and electrode properties, processing rate, reactant conversion, and inlet thickness were assumed. Under this basis of comparison, the results show: the space-time yield of the constant-depth electrode is larger, but the variable-depth electrode better utilizes the separator's and counterelectrode's surface area; the power requirement of the variable-depth electrode is greater; and, the current efficiency is parameter dependent, but for the majority of the situations likely to be found in wastewater processing, that in the constant-depth electrode is slightly higher. A simple capital-cost analysis shows that the variable-depth electrode may be less expensive if the costs associated with the separator and counterelectrode are greater than those which scale with the electrode volume.     

POROUS ELECTRODE THEORY ANALYSIS OF A VARIABLE-DEPTH, FLOW-BY POROUS ELECTRODE

A comparison has been made between a variable-depth and constant-depth, flow-by porous electrode in which a single metal ion deposition occurs in parallel with proton reduction. Porous-electrode theory was applied lo calculate the reactor's performance under limiting-current and below limiting-current conditions. The thickness profile of the variable-depth electrode was calculated—as first suggested by Kreysa—by constraining the solution phase potential drop across the electrode to remain constant and independent of streamwise position. For each reactor configuration, identical electrolyte and electrode properties, processing rate, reactant conversion, and inlet thickness were assumed. Under this basis of comparison, the results show: the space-time yield of the constant-depth electrode is larger, but the variable-depth electrode better utilizes the separator's and counterelectrode's surface area; the power requirement of the variable-depth electrode is greater; and, the current efficiency is parameter dependent, but for the majority of the situations likely to be found in wastewater processing, that in the constant-depth electrode is slightly higher. A simple capital-cost analysis shows that the variable-depth electrode may be less expensive if the costs associated with the separator and counterelectrode are greater than those which scale with the electrode volume.     

POROUS ELECTRODE THEORY ANALYSIS OF A VARIABLE-DEPTH,FLOW-BY POROUS ELECTRODE

A comparison has been made between a variable-depth and constant-depth, flow-by porous electrode in which a single metal ion deposition occurs in parallel with proton reduction. Porous-electrode theory was applied to calculate the reactor's performance under limiting-current and below limiting-current conditions. The thickness profile of the variable-depth electrode was calculated—as first suggested by Kreysa—by constraining the solution phase potential drop across the electrode to remain constant and independent of streamwise position. For each reactor configuration, identical electrolyte and electrode properties, processing rate, reactant conversion, and inlet thickness were assumed. Under this basis of comparison, the results show: the space-time yield of the constant-depth electrode is larger, but the variable-depth electrode better utilizes the separator's and counterelectrode's surface area; the power requirement of the variable-depth electrode is greater; and, the current efficiency is parameter dependent, but for the majority of the situations likely to be found in wastewater processing, that in the constant-depth electrode is slightly higher. A simple capital-cost analysis shows that the variable-depth electrode may be less expensive if the costs associated with the separator and counterelectrode are greater than those which scale with the electrode volume.     

Modified transparent SnO2 electrodes as efficient and stable cathodes for oxygen reduction

The aim of this work is to develop an efficient and stable transparent electrode for the reduction of dissolved oxygen, to be used for characterising biofilm formation in seawater and scale deposit, both by optical observations and electrochemical experiments. It was achieved by depositing a transparent conductive tin dioxide film on a glass substrate and modifying the surface by a very small gold charge. A reduction kinetics of dissolved oxygen as fast as that for a massive gold electrode has been obtained with a few monolayer only equivalent gold deposit via a simple chemical treatment. The long term stability has been checked, opening the way for practical applications. Electrochemical impedance spectroscopy was used to analyse the working conditions of the modified electrode. It is shown that SnO₂ is operating in the cathodic regime under weak depletion conditions with a surface-state mediated charge transfer.     

Modeling of an electrically rechargeable alkaline Zn-air battery

The charging and discharge behavior of an electrically rechargeable alkaline Zn-air battery consisting of a porous Zn/ZnO electrode on the negative side and a porous O₂ electrode on the positive side has been investigated. Galvanostatic experiments have been performed and a one-dimensional numerical model has been developed to analyze these experimental data. The cell voltages, the Zn electrode potentials versus Zn reference, and the O₂ electrode potentials versus Zn reference calculated with this model are in fairly good agreement with the corresponding experimental values. The unwanted redistribution of Zn per cycle is predicted to decrease with increasing cycle number. The numerical model is expected to be useful when optimizing zinc cell designs for specific applications.     

质子膜燃料电池(PEMFC)多孔电极极化的两尺度分析

针对PEMFC(Proton Exchange Membrane Fuel Cell)多孔电极微结构的特征,提出一个分析该多孔电极极化的两尺度新方法,建立了能够同时在团簇微观和电极宏观两尺度上描述多孔电极内反应和传质、传荷耦联过程的理论模型。该两尺度模型方程为一非线性二阶微分方程组,给出了求解该数模的ADM(Adomian Decomposition Method)与有限差分(Newman′s BAND(J))相结合的便捷方法。还给出了氢PEMFC多孔阴极极化的计算实例,与传统的电极单尺度模型相比,包含微团尺度传质影响的两尺度模型预测值与极化实验数据能更好相符。提出的两尺度新方法也可被相似的多相催化反应系统理论分析所借鉴。     

基于模拟退火算法的真实多孔电极中热-质传递的研究

电极中的离子-电子传递和传热显著影响着电化学储能性能。深入研究多孔电极中的热-质传递现象这一典型的介尺度问题，对高性能电化学储能器件的设计具有重要意义。采用一种基于改进的状态更新的随机重建方法和动态退火系数相结合的模拟退火算法，将图像分割后的二维SEM图重构为真实的三维多孔电极。通过重构多孔电极和PNP方程与傅里叶定律，建立真实多孔电极中的离子传递和电极导热模型。结果表明，当充电时间为0.1个平板充电弛豫时间时，离子主要吸附在多孔电极骨架相与体相的接触面上，且离子倾向于从截面边缘往中心迁移。由于实际的导热距离远小于多孔电极厚度，多孔电极中的热弛豫时间远小于平板的热弛豫时间。     

Properties and applications of electrodes covered with a porous diaphragm—2. Theoretical and practical aspects of electrosynthesis in single compartment electrolysis cells

The use of porous coverings on the counterelectrode for the reduction of the rate of loss reactions in single compartment electrolytic reactors has been studied. The theoretical current efficiencies for various overall reaction schemes have been calculated. The method has been tested for the electrosynthesis of potassium permanganate, ceric sulphate and sodium hypochlorite. Considerably improved reactor performance was realised. The experimental performance was in accord with that calculated theoretically.