碳烟颗粒掺杂铅基复合阳极的制备及电化学性能研究

本文采用一种快速、低成本的方法制得纳米碳材料-碳烟颗粒(C_H),并通过粉末冶金和机械合金化技术制备出铅/碳烟颗粒(Pb/C_H)复合阳极材料,利用纳米碳材料高比表面积和高催化活性等优点,提高铅基阳极的析氧电催化性。使用场发射扫描电子显微镜(FE-SEM)、傅里叶红外光谱(FTIR)、循环伏安曲线(CV)和线性扫描伏安曲线(LSV)等测试进行表征。C_H呈疏松的球链状,具有丰富的羰基和羟基功能团,是良好的电子和质子传递载体。随着C_H含量增加, Pb/C_H复合阳极的析氧超电位降低。Pb/1.5 wt.% C_H复合阳极与纯Pb和传统Pb/0.75 wt.% Ag阳极相比,其表观交换电流密度分别提高3和2个数量级。在模拟锌电积条件下,其析氧电位低于铅银合金阳极20 mV,较纯铅阳极降低133 mV,具有优异的析氧电催化活性。     

锌电积用Pb/Pb-MnO2复合电催化阳极的制备及性能

采用复合电镀技术制备Pb/Pb-MnO2复合电催化阳极,研究MnO2微粒晶型与粒径、电极构置、施镀时间和添加剂等对镀层中微粒含量的影响,利用正交实验确定阳极制备的最优条件,运用循环伏安和恒流极化等手段对复合阳极的析氧电催化性能进行评价.结果表明:通过工艺优化,可在氟硼酸盐镀铅体系中实现Pb基体上Pb-MnO2复合镀,获得MnO2微粒含量为1%～10%(质量分数)的复合镀层;模拟工业锌电积过程中,电解初始阶段复合阳极电位相比铅阳极降低约300 mV,经过24 h电解后,其稳定电位仍比铅阳极低100 mV,与工业Pb-Ag(0.6%,质量分数)阳极的稳定电位相当.     

锌电积工业用新型泡沫铝/Pb-0.6 wt%Ag合金复合阳极电化学性能研究

为改善传统锌电积阳极存在的高析氧过电位和高银含量的缺陷,本文发明了一种新型泡沫铝/Pb-0.6 wt%Ag复合阳极。采用计时电位法,扫描电镜,交流阻抗和塔菲尔测试方法对比研究了在160 g/L H2SO4极化72 h后泡沫铝/Pb-0.6 wt%Ag复合阳极和Pb-0.6 wt%Ag阳极的电化学性能。结果表明：泡沫铝/Pb-0.6 wt%Ag复合阳极的阳极膜比Pb-0.6 wt%Ag阳极的更平整,且抗腐蚀能力更强。此外,泡沫铝/Pb-0.6 wt%Ag复合阳极的稳定阳极电位更小,与其通过计时电位法和交流阻抗获得的高PbO2,低PbO, PbO?PbSO4含量和低Rct值一致。而且还发现泡沫铝/Pb-0.6 wt%Ag复合阳极具有更优异的析氧反应行为。     

Ti/Co3O4/RuO2-IrO2纳米结构阳极电催化析氧研究

目的 研发含纳米结构Co3O4中间层的Ti/Co3O4/RuO2-IrO2阳极,并对其电化学析氧性能进行研究,以提升Ti/RuO2-IrO2金属氧化物阳极的电化学析氧性能。方法 在Ti基底上电沉积制备Co(OH)2,烧结形成Co3O4纳米片结构,随后采用热分解工艺在Ti/Co3O4表面制备RuO2-IrO2电催化层,从而构建了Ti/Co3O4/ RuO2-IrO2复合阳极。使用透射电子显微镜(TEM)、扫描电子显微镜(SEM)、X-射线衍射仪(XRD)和电化学工作站对涂层的微观表面形貌、物相组成、电化学性能等进行观察与分析。结果 SEM显示出Ti/Co3O4纳米片上RuO2-IrO2的负载量随涂刷次数增加逐渐增多,最终完全遮盖Co3O4纳米片中间层。且随着RuO2- IrO2前驱体溶液涂覆次数的增加,XRD观察到RuO2-IrO2衍射峰强度在逐渐增大。TEM测试显示Co3O4中间层是由纳米颗粒堆叠组成且具有多孔结构。电化学极化曲线测试表明,涂覆三次RuO2-IrO2层的含Co3O4中间层阳极析氧电位最低,当电流密度达到10 mA/cm²时,析氧电位仅为1.326 V(vs. SCE),低于无中间层的Ti/RuO2-IrO2阳极(1.413 V)。循环伏安测试表明,Ti/Co3O4/RuO2-IrO2阳极的伏安电量达到62.83 mC/cm²,相较于Ti/RuO2-IrO2阳极的23.65 mC/cm²提高了166%。稳定性能试验表明,在经过1 000次循环稳定性试验后,加入Co3O4纳米片中间层的复合阳极的伏安电量降低了35.94%,低于无中间层阳极48.88%的伏安电量损耗率。循环极化试验后的Ti/Co3O4/RuO2-IrO2复合阳极的电化学活性仍明显优于循环极化试验前的Ti/RuO2-IrO2阳极。结论 Co3O4纳米片中间层的加入使得Ti/Co3O4/RuO2-IrO2阳极的电催化析氧性能和稳定性都得到了提升。     

Nd对锌电积用Pb-Ag合金阳极性能的影响

采用恒流极化、失重法和抗拉强度测试研究不同含量Nd的加入对锌电积用铅银合金阳极主要性能(稳定阳极电位、耐腐蚀性能及力学性能)的影响,并在此基础上采用循环伏安(CV)和计时电位(CP)等电化学手段对恒流极化条件下Nd的作用机理进行研究。结果表明:0.03%Nd(质量分数)加入可以将Pb-Ag合金的抗拉强度提高21.8%;锌电积条件下,铅阳极表面腐蚀膜主要成分为PbO2及PbSO4,Nd加入可以抑制PbSO4的形成,从而明显降低阳极腐蚀速率;由于Nd能降低析氧过电位,且对高阻抗PbSO4的生成具有抑制作用,使得Pb-Ag合金的阳极电位亦有一定程度的下降。Nd对锌电积阳极主要性能均有较大程度的改进作用,是很好的锌电积阳极改性剂,具有较好的工业应用前景。     

烧结温度对Ti/TiN_(x)/Mn_(2)O_(3)阳极涂层性能的影响EI北大核心CSCD

采用热分解工艺在Ti/TiN_(x)表面制备了Mn2O3催化层,研究了制备过程中烧结温度对Ti/TiN_(x)/Mn2O3阳极材料析氧电催化性能的影响。通过SEM、XRD、Raman、XPS等表征方法对Mn2O3催化层的表面微观形貌和晶体结构进行分析;通过Tafel、LSV、恒流极化、EIS、ECSA等电化学测试手段对阳极材料的耐腐蚀性能、析氧催化活性进行分析。结果表明:烧结温度对Ti/TiN_(x)/Mn2O3阳极材料的表面微观结构、Mn的价态、耐电化学腐蚀性能以及电催化性能具有较大的影响。当烧结温度为200℃时,阳极材料表面的Mn2O3催化层致密平整且结晶性最好。随着烧结温度的升高,Mn2O3催化层产生较多的裂纹,同时氧空位的含量逐渐减少,Mn(Ⅳ)逐渐增多,参与电化学反应的电极表面的活性位点数量大幅降低,抑制了析氧动力学。     

Pb-0.3%Ag/Pb-CeO2复合阳极材料电化学性能

采用双脉冲电沉积,在Pb-0.3%Ag(质量分数,下同)合金基体表面制备了Pb-0.3%Ag/Pb-CeO2复合阳极材料,研究了不同正向脉冲平均电流密度(2~5 A·dm-2)和镀液中CeO2颗粒浓度(0~20 g/L)下制备的复合阳极材料电化性能,在50 g·L-1 Zn2+,150 g·L-1 H2SO4,35℃溶液中测试了阳极极化曲线、循环伏安曲线和塔菲尔曲线,获得了析氧动力学参数、伏安电荷、腐蚀电位和腐蚀电流。结果表明:在正向脉冲平均电流密度为3 A/dm2和镀液中CeO2颗粒浓度为15 g/L下制备的Pb-0.3%Ag/Pb-CeO2复合阳极材料在[ZnSO4+H2SO4]溶液中具有较高的电催化活性,较低的析氧过电位,较好的电极反应可逆性和耐腐蚀性。在[ZnSO4+H2SO4]溶液中,复合阳极材料在测试电流密度500 A/m2下的析氧过电位为1.134V,比Pb-1%Ag合金降低37 mV;腐蚀电流为1.97×10-4 A,明显低于Pb-1%Ag合金,表现出了良好的耐腐蚀性能。     

循环伏安法对新型阳极的电化学性能研究

通过对成分相同、电化学性能相同、重量相同、长度相同的常规方条型阳极与长直翼型阳极循环伏安对比实验,研究计算和分析评价两者的阳极(积分)极化面电阻率与阳极(积分)极化面电阻,确定新型阳极的发生电流与其构型及表面积增加的相关性,以及对复合阳极的循环伏安测试,研究铝-镁复合阳极的电化学性能。     

《材料保护》2010年第11期

醋酸锰体系中钛材电沉积MnOx阳极的析氧催化性能 过去,对钛材在醋酸锰[Mn（CH3COO）2]电解液中电沉积MnOx层作析氧催化材料研究不充分。通过X射线衍射确定了MnOx沉积层的晶型,用扫描电镜技术观察其表面形貌;以循环伏安、极化曲线和电化学阻抗等方法测试了MnOx沉积层电极的电化学性能,探讨了MnOx沉积层电极结构、形貌与电催化性能的关系。     

Al／Pb-Ag阳极在锌电积过程中的阳极行为和微观结构

采用循环伏安曲线（CV）和电化学交流阻抗谱（EIS）研究Pb-0.8%Ag 和Al/Pb-0.8%Ag阳极在最初24 h锌电积过程中的阳极行为和析氧动力学。结果表明：2种阳极材料在阳极极化过程中的阳极行为和动力学的多种变化表明阳极表面膜的形成和稳定。与传统的Pb-0.8%Ag阳极相比,Al/Pb-0.8%Ag阳极具有较长的极化时间。在最初的电积过程中,阳极表面中间产物的转变使2种阳极都表现出较高的析氧电位。随着析氧电位降低,析氧反应速率可以由阳极表面最初的生成物和中间产物S-OHads推断。随着电积的持续进行,Al/Pb-0.8%Ag阳极的析氧电位逐渐降低,Al/Pb-0.8%Ag阳极比Pb-0.8%Ag 阳极先达到稳定状态。电积24 h后,阳极电位由阳极表面的生成物和中间产物控制。采用扫描电子显微镜观察Al/Pb-0.8%Ag 和Pb-0.8%Ag阳极锌电积24 h后的微观形貌。     

聚苯胺对锌电积用复合惰性阳极材料电化学性能的影响(英文)

为了寻找一种可以替代锌电积用 Pb-Ag 合金的阳极材料,通过 PANI(聚苯胺)、WC(碳化钨)颗粒与 Pb2+的双脉冲电沉积,在 Al 合金基体上制备了 Al/Pb-PANI-WC 复合惰性阳极材料。测试了镀液中不同 PANI 浓度下制备的惰性阳极材料的阳极极化曲线、循环伏安曲线和塔菲尔极化曲线,采用扫描电镜考察复合惰性阳极材料的微观组织特征。结果表明:当将制备镀液中 PANI 浓度控制在 20 g/L 时,Al/Pb-PANI-WC 复合惰性阳极材料的微观组织和成分分布均匀,在含 50 g/L Zn2+、150 g/L H2SO4的 35 °C锌电积液中具有较高的电催化活性、较好的电极反应可逆性和耐腐蚀性,在电流密度 500 A/m2和 1000 A/m2下的析氧过电位与 Pb-1%Ag 合金相比分别降低了 185 mV 和 166 mV。     

Depolarised gas anodes for aluminium electrowinning

Consumable carbon anodes are used in the electrowinning of aluminium by the Hall-Heroult process.Emissions of CO2 may be eliminated by introducing an inert oxygen evolving anode,which however will require a higher anode potential.An alternative approach is to use a natural gas or hydrogen gas anode to reduce the CO2 emissions and lower the anode potential.Preliminary laboratory experiments were carried out in an alternative molten salt electrolyte consisting of CaCl2-CaO-NaCl at 680 °C.Porous anodes of platinum and tin oxide were tested during electrolysis at constant current.The behaviour of inert anode candidate materials such as tin oxide and nickel ferrite were also studied.     

Electrochemical impedance spectroscopy evaluation of behaviour of Pb–Ag anodes for zinc electrowinning

Abstract

Pb–0·5–0·7Ag anodes are widely used in the industry of zinc electrowinning. Two commercial lead anodes containing 0·56 and 0·69%Ag were studied by electrochemical impedance spectroscopy to evaluate their electrochemical activity. An industrial acid zinc sulphate electrolyte containing glue and chloride ion, but without manganese addition, was considered. In this study, 5 h of electrolysis at a density of 50 mA cm^?2 (currently used in practice) and also 6 h of potential decay were made to represent electrowinning periods of maintenance both at 38°C. During the 5 h polarisation, the average double layer capacity of Pb–0·56Ag alloy was higher (～9%) than that of Pb–0·69Ag alloy. During the first hour of potential decay, the Warburg impedance controls the electrochemical reaction. For the period from the second to sixth hour, the double layer capacity decreased with immersion time, and the charge transfer resistance increased with time. During the potential decay, the average charge transfer resistance of Pb–0·69Ag anode was higher (～52%) than that of Pb–0·56Ag anode.     

Developing and studying the properties of Pb–TiO2 alloy coated lead composite anodes for zinc electrowinning

Abstract

A new anodic material for zinc electrowinning from sulphate electrolytes has been developed. This is a lead–titanium alloy coated lead composite electrode containing titanium nanoparticles. The titanium is present in the lead matrix as n-type TiO₂. It has been established that the optimal content of the Ti in the composite coatings is about 0·5 wt-%. The behaviour of the lead–titanium anodes during the zinc electrowinning has been studied by means of galvanostatic polarisation investigations. The depolarising of the anodic reaction at lead–titanium composite electrodes is attributed to the increased anode area during continued polarisation. The processes occurring on the lead–titanium anodes during zinc electrowinning have been studied by cyclic voltammetry. The surface morphology of the composite lead–titanium electrodes was investigated by scanning electron microscopy.     

牺牲阳极材料的研究现状

 综述了牺牲阳极材料的研究现状和目前常用的铝基、锌基和镁基等三种牺牲阳极材料的基本化学成分和性能特点,分析了合金元素的作用,并对牺牲阳极的一些新发展和应用情况作了介绍.     

Effect of MnO4− and silver content on electrochemical behaviour of Pb–Ag alloy anodes during potential decay periods

The effect of MnO₄^? and silver content on electrochemical behaviour of five commercial Pb–Ag alloy anodes was studied in acid zinc sulphate electrolyte with and without MnO₄^? ions at 38 °C during potential decay periods. When the anodes were immersed into acid zinc sulphate electrolyte without MnO₄^? ions, the Pb–0.72%Ag anode entered complete passivation state in the shortest time among the five anodes, followed by anodes Pb–0.67%Ag, Pb–0.60%Ag, Pb–0.58%Ag and Pb–0.29%Ag– 0.1%Ca by measurement of open circuit potential. During immersion of the anodes, MnO₄^? ions accelerated the passivation and increased the corrosion current density of the anodes. After immersion in zinc electrolyte with MnO₄^?, the anode Pb–0.72%Ag had the best corrosion resistance, followed by anodes Pb–0.67%Ag, Pb–0.60%Ag, then the close anodes Pb–0.58%Ag and Pb–0.29%Ag– 0.1%Ca by the electrochemical impedance spectroscopy (EIS) analysis.