二元混合铜颗粒流化床电极的研究

以两种不同粒径的铜颗粒构成的二元混合颗粒为阴极颗粒,浓度低于1 g/L的硫酸铜溶液为电解液,在横截面为50 mm×15 mm的流化床电极中探讨床层膨胀率、混合颗粒粒径比及质量比对铜沉积速率、电流效率的影响.研究结果表明,二元混合颗粒可以显著的强化传质过程,提高铜的沉积速率;混合颗粒床层膨胀率、粒径比和质量比对铜沉积速率、电流效率有重要影响,都存在一最佳值,即膨胀率约20%、大颗粒质量分率约75%、粒径比为 2.09.在此条件下沉积速率最大,为 1.6 g/(m2·h),约为单粒径颗粒床层的 2.5倍,电流效率最高,达到约88%.     

发泡铜阴极电沉积法回收酸性镀铜废液中的铜

用发泡铜作阴极材料, 从稀的酸性镀铜废液中电沉积回收金属铜,测定了阴极极化曲线,考察了pH值、电解液循环速率、电流密度等工艺参数对阴极电流效率的影响. 结果表明:用发泡铜作阴极材料,可有效地处理含铜废液和回收金属铜,将含Cu2+ 200 mg/L的废液在1.2 A/dm2表观电流密度下处理至含Cu2+ 0.5 mg/L以下,平均电流效率可达85%以上.     

扩散控制下固定床电化学反应器研究（1）理论研究

建立了固定床电化学反应器在扩散控制下的反应器模型，并对模型的简化进行了探讨，从理论上研究了床层几何尺寸、填充材料比表面积、电解液相有效电导率、反应物进口浓度、电解液流速对床层内电势分布的影响。     

扩散控制下固定床电化学反应器研究：（I）理论研究

建立了固定床电化学反应器在扩散控制下的反应器模型，并对模型的简化进行了探讨，从理论上研究了床层几何尺寸、填充材料比表面积、电解液相有效电导率、反应物进口浓度、电解液流速对床层内电势分布的影响。     

流化床电极处理低浓度硫酸铜废水研究

以纯铜颗粒为阴极颗粒,低浓度硫酸铜溶液为电解液,在截面为50mm×15mm的矩形流化床电极中,探讨床层膨胀率、颗粒粒径、硫酸浓度、Cu~(2+)浓度以及电流密度对电流效率和铜沉积速率的影响,为确定流化床电极适宜的操作条件提供参考。     

填充床电极反应器中典型有机电合成反应系统的选择性分析

典型的有机电合成反应,常伴有相互竞争的电极副反应和均相反应,增加电极极化以提高反应速率会使选择性明显降低。填充床电极具有大的内表面,能在相对低的极化下,达到较高的表观电流密度,有利于缓解反应速率和选择性之间的突出矛盾。本文对填充床电极微分反应器（PBEDR）中典型有机电合成反应过程进行了理论分析,重点在于床层内超电势横向分布对选择性的影响。建立了描述超电势分布的普遍化数学模型,归纳出表征电极极化和副反应影响的量纲1数μ和ω,并用ADM（Adomian’s decomposition method）对该非线性微分方程模型求解;所获得的逼近解代数表达式,可方便地计算不同参数下超电势分布对平均选择性的影响,而毋需反复求解模型微分方程。最后给出了PBEDR硝基苯电还原制对氨基苯酚选择性分析实例,优化了反应器特征尺寸（填充床电极厚度）。结果证明：理论计算与实验数据令人满意地一致。     

固定床电化学反应器研究(Ⅰ)床层内电势分布的实验测定

建立了测定固定床电化学反应器床层内电势分布的实验装置,由计算机采样测定了床层内的电势分布,并将实验结果与文献中的模型计算结果进行了比较,证明了文献所建立的反应器模型和模型方程求解方法的正确性.在不同操作模式下用实验方法考察了各因素对床层内电势分布的影响.     

固定床电化学反应器研究(Ⅰ)床层内电势分布的实验测定

建立了测定固定床电化学反应器床层内电势分布的实验装置,由计算机采样测定了床层内的电势分布,并将实验结果与文献中的模型计算结果进行了比较,证明了文献所建立的反应器模型和模型方程求解方法的正确性.在不同操作模式下用实验方法考察了各因素对床层内电势分布的影响.     

固碳产甲烷微生物阴极能质传输特性数值模拟

固碳产甲烷微生物电合成系统以附着其电极表面的生物膜为催化剂，可以在处理废水的同时将CO₂转化为甲烷，极具应用前景。微生物阴极是该系统的核心部件之一，其表面生物膜内的能质传输特性极大地影响系统性能。针对微生物阴极能质传输特性尚不明确的问题，推导了微生物阴极电极反应动力学方程（Nernst-Monod方程），构建了耦合生化/电化学反应的物质传输理论模型，研究了不同阴极电势、生物膜电导率以及孔隙率对阴极生物膜内电荷及物质传输的影响规律。研究结果表明当阴极电势高于-0.5 V (vs SHE)时，随阴极电势的降低生物膜内电流密度增大，底物浓度降低；但当阴极电势降低至-0.5 V(vs SHE)后，生物膜消耗电子还原底物的能力几乎达到饱和；低电导率（<10^-3 S/m）会导致生物膜内形成明显的电势差，使得底物利用速率降低，严重影响微生物阴极的性能；生物膜孔隙率控制在0.4时，微生物阴极可达到最佳电流密度。     

填充床鼓泡电化学反应器行为特性研究──Ⅰ.丙烯阳极直接氧化的数学模拟

本文建立了填充床鼓泡电化学反应器的一维数模．该模型既考虑了反应动力学，也考虑了体系的基本传递特性．模拟结果可以描述床层的径向电势、电流和浓度分布．     

Stable interfaces constructed by concentrated ether electrolytes to render robust lithium metal batteries

Lithium metal batteries (LMBs) are highly considered as promising candidates for next-generation energy storage systems.However,routine electrolytes cannot tolerate the high potential at cathodes and low potential at anodes simultaneously,leading to severe interfacial reactions.Herein,a highly concentrated electrolyte (HCE) region trapped in porous carbon coating layer is adopted to form a stable and highly conductive solid electrolyte interphase (SEI) on Li metal surface.The protected Li metal anode can poten-tially match the high-voltage cathode in ester electrolytes.Synergistically,this ingenious design promises high-voltage-resistant interfaces at cathodes and stable SEI with abundance of inorganic components at anodes simultaneously in high-voltage LMBs.The feasibility of this interface-regulation strategy is demonstrated in Li | LiFePO4 batteries,realizing a lifespan twice as long as the routine cells,with a huge capacity retention enhancement from 46.4％ to 88.7％ after 100 cycles.This contribution proof-of-concepts the emerging principles on the formation and regulation of stable electrode/electrolyte inter-faces in the cathode and anode simultaneously towards the next-generation high-energy-density batteries.     

Carbon-air fuel cell without a reforming process

This paper describes a direct carbon-air fuel cell (DCFC) which uses a molten hydroxide electrolyte. In DCFCs, carbon is electrochemically directly oxidized to generate the power without a reforming process. Despite its compelling cost and performance advantages, the use of molten metal hydroxide electrolytes has been ignored by DCFC researches, primarily due to the potential lack of invariance of the molten hydroxide electrolyte caused by its reaction with carbon dioxide. This paper describes the electrochemistry of a patented medium-temperature DCFC based on molten hydroxide electrolyte, which overcomes the historical carbonate formation.To date, four successive generations of DCFC prototypes have been built and tested to demonstrate the technology, all using graphite rods as their fuel source. These cells all used a simple design in which the cell containers served as the air cathodes and successfully demonstrated delivering more than 40 A with the current density exceeding 250 mA/cm². The cathode is of non-porous structure made of an inexpensive Fe-Ti alloy, and gaseous oxygen is introduced into the cell by bubbling humid air through the electrolyte. Results obtained indicated that the cell operation was under a mixed Ohmic-mass transfer control. Anode and cathode reaction mechanisms are also discussed.     

Cycling of lithium/metal oxide cells using composite electrolytes containing fumed silicas

The effect on cycle capacity is reported of cathode material (metal oxide, carbon, and current collector) in lithium/metal oxide cells cycled with fumed silica-based composite electrolytes. Three types of electrolytes are compared: filler-free electrolyte consisting of methyl-terminated poly(ethylene glycol) oligomer (PEGdm, M_w=250)+lithium bis(trifluromethylsufonyl)imide (LiTFSI) (Li:O=1:20), and two composite systems of the above baseline liquid electrolyte containing 10-wt% A200 (hydrophilic fumed silica) or R805 (hydrophobic fumed silica with octyl surface group). The composite electrolytes are solid-like gels. Three cathode active materials (LiCoO₂, V₆O₁₃, and Li_xMnO₂), four conducting carbons (graphite Timrex® SFG 15, SFG 44, carbon black Vulcan XC72R, and Ketjenblack EC-600JD), and three current collector materials (Al, Ni, and carbon fiber) were studied. Cells with composite electrolytes show higher capacity, reduced capacity fade, and less cell polarization than those with filler-free electrolyte. Among the three active materials studied, V₆O₁₃ cathodes deliver the highest capacity and Li_xMnO₂ cathodes render the best capacity retention. Discharge capacity of Li/LiCoO₂ cells is affected greatly by cathode carbon type, and the capacity decreases in the order of Ketjenblack>SFG 15>SFG 44>Vulcan. Current collector material also plays a significant role in cell cycling performance. Lithium/vanadium oxide (V₆O₁₃) cells deliver increased capacity using Ni foil and carbon fiber current collectors in comparison to an Al foil current collector.     

Electrochemical reduction of carbon dioxide on flat metallic cathodes

The most important methods for the electrochemical reduction of carbon dioxide on flat metallic cathodes have been systematically summarized using a novel classification approach. In contrast to the usual classification systems that were based solely on the products of electrolysis, the electroreduction procedures have been grouped according to both the nature of the cathode (sp or d group metal electrodes) and the solvent used for the supporting electrolyte (aqueous or nonaqueous solutions). The new classification system allows the identity of the electroreduction product to be better related to the nature of the metallic electrode and the supporting electrolyte. Similar reduction products are formed by each of the four possible combinations of electrodes and supporting electrolytes (sp group metals in aqueous and nonaqueous electrolytes, and d group metals in aqueous and nonaqueous electrolytes, respectively). The discussion has included both synthetic aspects and mechanistic considerations. Of special interest in this review is the discussion of procedures for the selective preparation of formic acid and for the manufacturing of hydrocarbons and/or alcohols using carbon dioxide as the carbon source.     

Electrocatalytic oxygen reduction on single-walled carbon nanotubes supported Pt alloys nanoparticles in acidic and alkaline conditions

The objective of this study is to improve the catalytic activity of platinum by alloying with transition metal (Pd) in gas diffusion electrodes (GDEs) by oxygen reduction reaction (ORR) at cathode site and comparison of the acidic and alkaline electrolytes. The high porosity of single-walled carbon nanotubes (SWCNTs) facilitates diffusion of the reactant and facilitates interaction with the Pt surface. It is also evident that SWCNTs enhance the stability of the electrocatalyst. Functionalized SWCNTs are used as a means to facilitate the uniform deposition of Pt on the SWCNT surface. The structure of SWCNTs is nearly perfect, even after functionalization, while other types of CNTs contain a significant concentration of structural defects in their walls. So catalysts supported on SWCNTs are studied in this research. The electrocatalytic properties of ORR were evaluated by cyclic voltammetry, polarization experiments, and chronoamperometry. The morphology and elemental composition of Pt alloys were characterized by X-ray diffraction (XRD) analysis and inductively coupled plasma atomic emission spectroscopy (ICP-AES) system. The catalytic activities of the bimetallic catalysts in GDEs have been shown to be not only dependent on the composition, but also on the nature of the electrolytes. The GDEs have shown a transition from the slow ORR kinetics in alkaline electrolyte to the fast ORR kinetics in the acidic electrolyte. The results also show that introduction of Pd as transition metal in the Pt alloys provides fast ORR kinetics in both acidic and alkaline electrolytes. The performance of GDEs with Pt–Pd alloy surfaces towards the ORR as a function of the alloy’s overall composition and their behavior in acidic electrolyte was also studied. These results show that the alloy’s overall composition and also the nature of the electrolytes have a large effect on the performance of GDEs for ORR.     

浸渗法制备固体氧化物燃料电池复合阴极研究进展

中低温化是目前固体氧化燃料电池研究的主要方向,影响其发展的主要问题是电解质及阴极材料的研制.浸渗法制备复合阴极能够显著提高电池在中低温下的电化学性能和效率,是目前研究的热点之一.本文介绍了近年来采用具有催化活性的电极材料、贵金属、氧离子传导材料等作为浸渗剂制备复合阴极的研究现状,并对其发展方向进行了展望.     

Design of experiments in electrochemical microfabrication

Electrochemical material etching techniques have attracted a significant amount of attention in the “wet” metal etching arena, as the process typically involves neutral salt electrolytes and is relatively safe to operate. There are also economical and environmental advantages associated with these techniques compared with competing etching methods.A new concept of electrochemical microfabrication on substrates has been developed. In the technique the workpiece, which is the anode in the electrochemical reactor, is placed closely to a tool, which is the cathode containing the micro-pattern. Selective pattern transfer results in a higher etching rate on the areas opposing “exposed” regions of the cathode, and lower etching rates in the areas directly opposite to the areas, on the cathode, covered by an insulator.In this investigation the electrochemical micro-patterning process has been evaluated and characterised in a vertical flow system described previously in literature. The experiments were carried out using copper disk anodes and patterned cathodes in a 0.1 M copper sulphate electrolyte. A 2⁴ factorial experimental design procedure was adopted to determine the influence of process parameters on the electrochemical microfabrication process in terms of variability in pattern transfer over the electrode's surface area.     

Zinc barrel electroplating using low cyanide electrolytes

The influence of plating conditions on the cathode efficiency of zinc barrel electroplating and the quality of deposited layers for low cyanide electrolytes is analysed. The investigations are carried out using factorial design methodology. The first part of the study shows how electrolyte components, such as brightening agent, sodium carbonate concentration, sodium hydroxide concentration, sodium cyanide concentration and zinc metal content, influence cathode efficiency and the morphology and the texture of the zinc electrodeposits. A mathematical model that fits experimental data is suggested and the pseudo three-dimensional plot of yield as a function of electrolyte composition for three significant component mixtures, brightening agent, sodium cyanide concentration and zinc metal content, is represented. The second part of the study shows how varying six process parameters influences current efficiency and metal thickness distribution. For the range studied, efficiency is affected by workload volume, current density, perforation and part size, but not by rotation speed and quantity of charge.     

Kinetic Studies on Electrochemical Antimony Removal from Concentrated Sulfuric Acid Systems

The aim of this study was to separate antimony from its acidic aqueous solution with an electrochemical method by cathodic deposition. For this purpose it is essential to know the electrochemical behavior of antimony. Electrochemical studies were conducted on systems in aqueous sulfuric acid solutions containing 20–30 % of antimony. Cyclic voltammetry and stripping experiments were carried out to characterize the removal or deposition process on cathodes of different materials, such as platinum, copper, or glassy carbon. Besides, several types of electrolytes prepared artificially from dissolved Sb₂O₃ and antimony standard were employed. The results showed that different species were included in the deposits, depending on the chosen cathode material, cathode potential, time of electrolysis, and type of electrolyte. The electrochemical deposition of antimony was confirmed by X‐ray diffraction experiments.     

Current efficiency in the Hall–He´roult process for aluminium electrolysis: experimental and modelling studies

Results are presented from a laboratory study of the influence of electrolyte composition, temperature, cathodic current density and interpolar distance on the current efficiency with respect to aluminium (CE). The current efficiency was determined from the weight gain of metal, in a laboratory cell designed to attain good and reproducible convective conditions, and with a flat cathode surface which ensures uniform cathodic current distribution. The cell is believed to more closely represent conditions in industrial cells than traditional small-scale cells, and is a good basis for an experimental study of the influence of isolated variable parameters on the current efficiency with respect to aluminium. The results show a nonlinear decrease of CE with increasing electrolyte temperature, a close to linear decrease of CE with increasing NaF/AlF3 ratio in the electrolyte, a slight increase of CE with increasing electrolyte CaF2 concentration, and no influence of electrolyte Al2O3 concentration on CE. A current efficiency model, based on previous work and theory of electrochemistry and mass transport, shows good agreement with the obtained results.