Innovation in Molten Salt Electrochemistry

简要介绍近3年武汉大学电化学研究中心在熔盐电化学方面的若干研究进展:1)熔盐电解固态化合物制备单质硅及其合金以及无机功能材料;2)适于高温熔盐的全密封长寿命Ag/AgCl参比电极和可负载微量粉末的金属腔(坑)工作电极新技术;3)“三相界线电化学”新概念以及描述三相界线在薄层固态化合物电解还原过程中扩展变化的薄层模型.Recent research development in molten salt electrochemistry at the Electrochemical Research Centre of Wuhan University is briefly reviewed. Attention is first paid on the preparation of silicon and its binary alloys, as well as oxide based functional materials. In addition, the quartz sealed Ag/AgCl reference electrodes suitable for high temperature molten salts are described. Focus is also given to two types of metal based cavity electrodes that are capable of loading micrograms of oxide powders and hence allow fast and reproducible measurements for the electrochemical behaviour of the powders in molten salts. The article finishes by highlighting the concept of “three-phase interline electrochemistry” in conjunction with reporting the preliminary results from the investigation of a simple "thin layer model" for the electrochemical reduction of solid AgCl in aqueous solution and solid SiO_(2)in molten salts.作者联系地址：武汉大学化学与分子科学学院电化学研究中心,武汉大学化学与分子科学学院电化学研究中心 湖北武汉430072 ,湖北武汉430072Author's Address: Electrochemical Research Centre, College of Chemistry and Molecular Science, Wuhan University, Wuhan 430072,Chin

Novel Molten-salt Electrolysis Processes towards Low-carbon Metallurgy

本文重点介绍“氯化物熔盐体系电解还原固态氧化物冶金过程的高效化”和“氯化物熔盐体系电裂解硫化物及熔融碳酸盐与熔融氧化物体系电分解氧化物无温室气体排放冶金”的研究进展，结合武汉大学的部分代表性工作阐述了相关技术的原理，以期揭示熔盐电解技术在节能减排和资源高效利用上的优势及其发展前景，为发展短流程、低碳高效的电化学冶金工业提供理论和技术支持。This review focuses on recent developments in molten-salt electrolytic metallurgical processes with respect to 1) high-efficiency metallurgical technologies via electrolytic reduction of solid oxides in molten chlorides and 2) zero-carbon-footprint electrochemical splitting metallurgical technologies. Initiating with an introduction on dynamic solid/solid/liquid three-phrase interlines electrochemistry for electrochemical reduction of solid cathode, the former aspect is discussed in terms of facilitating mass transfer throughout solid cathode, one-step production of functional alloy powders with the assistance of under-potential electroreduction of active metals and near-net-shape production of metal/alloy components. Whilst the latter is summarized by introducing some zero-carbon molten-salt electrolytic technologies including electro-splitting of solid sulfides in molten chlorides, electrometallurgical technology in molten carbonates and molten oxide electrolysis. With an attempt to demonstrate the proof-of-concept, the merits of molten-salt electrolytic technologies on environmental viability, energy-profitability and resource-utilization are also justified and highlighted, which, as hope, could form a basis for developing novel electrolytic processes for clean, energy-efficient and affordable metallurgy of materials.国家自然科学基金项目（No. 20125308，No. 50374052，No. 20573081，No. 20873093，No. 51071112）资助作者联系地址：武汉大学资源与环境科学学院，湖北 武汉 430072Author's Address: School of Resource and Environmental Sciences, Wuhan University, Wuhan 430072, Hubei, China通讯作者E-mail：[email protected]

Highly Efficient CO2 Utilization via Molten Salt CO2 Capture and Electrochemical Transformation Technology

高温熔融盐具有CO2吸收容量大、电化学窗口宽、高温下反应动力学快等特点,是利用清洁电能大规模捕集和资源化利用CO2颇具实用化潜力的电解液体系. 本文主要介绍作者课题组近十年关于高温熔盐CO2捕集与电化学资源化转化(MSCC-ET)技术的相关研究工作,包括熔融盐电解质对CO2的吸收、阴极过程动力学、电解条件对产物的影响、析氧阳极、电解过程能量效率和CO2捕获潜力,并展望了MSCC-ET技术的发展前景.The molten electrolytes exhibit high CO2 absorption capacities, wide electrochemical windows and excellent reaction kinetics, which are promising electrolyte candidates for efficient capture and electrochemical conversion of high-flux CO2 driven by renewable and clean electricity sources. This short review introduces the recent advancements of CO2 electroreduction achieved by the authors using molten salt CO2 capture and electrochemical transformation (MSCC-ET) technology, involving CO2 absorption kinetics, cathodic kinetics, controllable synthesis of carbon products with unique nanostructures, development of inert oxygen evolution anodes and CO2 conversion efficiency as well as energy efficiency. The challenges and prospects are also discussed based on the critical review.国家自然科学基金(51325102);国家自然科学基金(21673162);国家自然科学基金(51874211);科技部国际合作专项(2015DFA90750)通讯作者:汪的华E-mail:[email protected]:WANGDi-huaE-mail:[email protected]武汉大学资源与环境科学学院,湖北 武汉 430072School of Resources and Environmental Science, Wuhan University, Wuhan 430072, Hubei, Chin

The Adsorption Stability of Interface Corrosion Inhibitor

研究表明：在一定条件下，阳极脱附电位可作为评价缓蚀剂吸附稳定性的一个经验参数；缓蚀剂吸脱附诱导的电化学振荡是缓蚀体系的一种特殊失稳状态，即缓蚀剂吸附过程与电极反应中间吸附态产物耦合的结果；卤素离子的协同作用不仅可以提高某些有机缓蚀剂的吸附复盖度，而且可以增强其吸附稳定性；微分极化曲线是研究吸附稳定性的有效方法Some new results on the adsorption stability of interface corrosion inhibitor are presented. The concept of adsorption stability and the factors influencing the adsorption stability were discussed. It is shown that the anodic desorption potential can be employed to evaluate the adsorption stability of the inhibitor as an empirical character in some conditions. Electrochemical oscillations phenomena were observed for the first time on a rotating iron electrode in H2SO4 solution containing organic inhibitor in the active potential region. These potentiostatic current oscillations can occur under cathodic polarization, as well as under anodic plarization. The oscillation period, amplitude, incubation time and waveform changed with the applied potential and electrode rotating speed. The oscillations sustained even with strong stirring, but were inhibited by the codsorption of organic molecules and halides. This periodic behavior of oscillation may be attributed to the cycle between the partial desorptioon the iron surface. The synergistic effect of organic molecules and halides ions may enhance the adsorption stability of the inhibitor on the metal surface. A differential polarization curve method was proposed to study the adsorption stability and anodic desorption behaviors of the inhibitor.作者联系地址：武汉大学环境科学系Author's Address: Dept. of Environmental Sci., Wuhan Univ., Wuhan43007

The Adsorption desorption Behaviors of β phenylaminopropiophenone on iron in sulphuric acid solution

用极化曲线法研究了０．５ｍｏｌ·Ｌ－１硫酸溶液中β－苯胺基苯丙酮（ＰＡＰ）在铁－溶液界面的吸脱附行为及Ｃｌ－，Ｉ－的影响．结果表明，ＰＡＰ的吸附遵循Ｆｌｏｒｙ－Ｈｕｇｇｎｓ等温式；在较正的极化电位区出现阳极脱附现象．讨论了两种粒子联合吸附方式与浓度的关系，提出可根据吸附粒子的脱附电位与其浓度关系来推断联合吸附的理论模型The adsorption desorption behaviors of β phenylaminopropiophenone (PAP) on iron in 0.5 mol·L -1 H 2SO 4 solution with or without halide ions (Cl -,I -) were investigated by potentiostatic polarization measurement. The results show that the adsorption of PAP on iron surface follows Flory Huggins isotherm, the adsorption free energy parameter ( f ) is positive in H 2SO 4 solution; In the presence of 0.1 mol·L -1 Cl -1 , when C PAP ≤2×10 -5 mol·L -1 , f0 . A desorption phenomenon was observed at more positive potential region in anodic polarization curves. Furthermore, the anodic desorption potential ( E des ) of PAP+X - is independent of PAP concentration at lower concentration region, and E des vs. lg C PAP is a straight line at higher concentration region. The joint adsorption modes under different conditions were determined according to the above stated relation of E des to PAP concentrations as well as the adsorption free energy parameter f values.作者联系地址：武汉大学环境科学系Author's Address: Department of Environmental science, Wuhan University, Wuhan 43007

A Study of Adsorption Kinetics of β-phenylaminopropiophenone on Iron in Acid Solution

用计时电流法研究了０．５ｍｏｌ／ＬＨ２ＳＯ４溶液中β－苯胺基苯丙酮（ＰＡＰ）、卤素离子（Ｃｌ－，Ｉ－）在铁电极上的吸附动力学行为以及Ｃｌ－对ＰＡＰ吸、脱附速度的影响，求得了吸、脱附速度常数ｋａ、ｋｄ和吸附自由能参数ｆ值．结果表明，当ＰＡＰ发生化学吸附时，ｋａ比ｋｄ约大２个数量级，吸附粒子间存在吸引力．在电极表面已吸附有Ｃｌ－的条件下，且当ＰＡＰ浓度较低时发生静电吸附，ｋａ比ｋｄ约大４个数量级，吸附粒子间存在排斥力；浓度高时则发生化学吸附．The adsorption kinetics of β-phenylaminopropiophenone (PAP) on iron electrode in 0.5 mol/L H_2SO_4 solution with or without Cl~- were investigated by chronoamperometry. According to the following adsorption kinetic equation dθ/dt=kaCen-1(1-θ)nexp(fθ/2)-kdθexp(-fθ/2)The rate constants ka, kd as well as the adsorption free energy parameter f of PAP in sulfuric acid soltuion was calculated by used a computerized curve fitting program, the calculated ka, kd are in the order of 10~-1 mol/L s~-1 and 10~-3 s-1, respectively, f>0 in the concentration region of 5×10~-5 to 1×10~-3 mol/L of PAP. While in the 0.5 mol/L H_2SO_4 solution with 0.1 mol/L Cl-,the values of ka, kd are 66 mol/L s~-1 and 1.8×10~-3 s-1, respectively, f0 when CPAP=1×10~-3 mol/L. Otherwhere, authors proved that the PAP occurred electrostatic adsorption under former condition, and it is chemisorbed on the iron surface under latter condition.作者联系地址：武汉大学环境科学系Author's Address: Dept. of Envir. Sci., Wuhan Univ., Wuhan 43007

Studies of the Electrode Preparation of Electrode from Lead Carbonate for Lead acid Battery Ⅰ The activation of the PME

用循环伏安法研究了ＰｂＣＯ３ 粉末微电极转化为ＰｂＳＯ４ 电极的活化方法和条件．发现在２ ～２－５ ｍｏｌ／ＬＨ２ＳＯ４ 溶液中由ＰｂＣＯ３ 转化成ＰｂＯ２／ＰｂＳＯ４ 和ＰｂＳＯ４／Ｐｂ 电极时，以不对称交变讯号活化（ 化成） 后，其循环伏安性能与由球磨机生产的ＰｂＯ 粉所制得的相应电极性能相近．对于负极，在含有乙炔黑胶体的Ｈ２ＳＯ４ 溶液中化成，由于碳胶粒在ＰｂＳＯ４ 晶体上的吸附，阻止了充放电过程中电极材料的收缩，同时增加了电极的导电性，从而促进活性物质的转化形成Lead carbonate which was an intermediate product in lead hydrometallurgy without pollution of lead vapor and sulfur dioxide was selected as electrode material of lead_acid batteries. In the present work,the performances of PbO 2/PbSO 4 or PbSO 4/Pb electrode transformed from PbCO 3 have been investigated by powder microelectrode technique combined with cyclic voltammetry.The results show that the CV characteristics of either negative or positive electrode prepared from PbCO 3 is as good as that of both electrodes made from lead oxide produced by mill machine,when a powder microelectrode with PbCO 3 transformed into PbSO 4 in 1.0 mol/L H 2SO 4 solution,and then activated to form Pb or PbO 2 using an unsymmetrical interchangeable signal( Q a/ Q c or Q c/ Q a being 0.2～0.4) in 2.0～2.5 mol/L H 2SO 4 solution.Furthermore,comparing the negative electrode activated in 2.5 mol/L H 2SO 4 solution containing 4% carbon colloid with one activated in the same H 2SO 4 solution concentration without ABC,the cyclic voltammetric characteristics of the former has been obviously improved.It is possible that the carbon colloid particles can be adsorbed on PbSO 4 crystals,which could increase the conductivity and reduce the shrinking of the electrode作者联系地址：武汉大学化学与环境科学学院!武汉430072,武汉大学化学与环境科学学院!武汉430072,武汉大学化学与环境科学学院!武汉430072,武汉大学化学与环境科学学院!武汉430072,武汉大学化学与环境科学学院!武汉430072Author's Address: Dept.of Chem.,Wuhan Univ.,Wuhan 43007

Activation Effect of Nano-Carbon Derived from CO2 on Lead Electrode in Sulfuric Aqueous Solution

负极板硫酸盐化是铅酸蓄电池早期容量下降、提前失效的主要原因之一. 利用碳材料制备活化剂加入电池电解液中，可以有效减少或修复不可逆硫酸盐化现象. 本文研究了一种新型高导电纳米碳材料—CO2高温熔盐电化学转化制备碳粉，对硫酸盐化铅盘电极的活化效果，结果表明，新型碳粉对于铅盘电极电量和电流效率的提升效果比乙炔黑和碳纳米管更显著，在一定浓度范围内对析氢无影响，碳粉的存在提高了电极活性物质间的导电性，并可在其表面吸附富集铅离子和提供还原位点，从而促进硫酸铅的溶解、抑制大颗粒硫酸盐晶体的产生，表明CO2高温熔盐资源化转化制备的碳粉作为一种新的铅蓄电池碳材料活化剂具有较好的发展潜力.Serious sulfation of the negative plate is one of the most popular reasons of the early failure of lead-acid battery. Addition of nano-carbon was proved to be effective for recovering the sulfated electrode and the property of the carbon material always plays an important role. In this work, a new kind of nano-carbon material with high electrical conductivity and good adsorption capability for heavy metal cations, which is electrochemically prepared from CO2 in molten carbonates, was tested as activation additive for the sulfated lead electrode by cyclic voltammetry and SEM measurements. The results showed that the as-prepared carbon can effectively enhance the activity of the sulphated lead electrode, super to acid-treated acetylene black and carbon nanotubes at the same concentration. No serious hydrogen evolution took place when the concentration of carbon was not higher than 1 g•L-1. It was also found that its activation effect is strongly dependent of its concentration in the solution. Based on the test results and SEM analysis, a possible activation mechanism of the carbon was proposed. The adsorption of the carbon powder at the surface and interface of the PbSO4 particles can enhance the conductivity of the electrode, promote the dissolution of the sulfate crystals through its capacity of the absorption of plumbous ions and provide more active site for reduction and oxidation. However, too much adsorbed carbon will block the pathway of ions transportation within the porous electrode. The results suggest that the carbon powder derived from CO2 could be a new kind of activator for the electrode of lead acid battery.科技部国际科技合作专项（电网2015DFA90750）、湖北省自然科学基金创新群体项目（2015CFA017）和国家电网总部科研项目资助作者联系地址：1.武汉大学资源与环境科学学院，湖北，武汉，430072；2.河南省电力公司电力科学研究院，河南，郑州，450052；3.江苏华富储能新技术股份有限公司，高邮，江苏， 225600Author's Address: 1.School of Resource and Environmental Sciences, Wuhan University, Wuhan 430072, Hubei, China；2.Electric Power Research Institute of Henan Electric Power Corporation, Zhengzhou 450052, Henan, China；3.Jiangsu Fu Hua New Technology of Energy Storage co., LTD., Gaoyou , 225600 Jiangsu, China通讯作者E-mail：[email protected]