DSA电极电催化性能研究及尚待深入探究的几个问题

钛基氧化物涂层电极(DSA^®)由于其对阳极析氯、阳极析氧、有机污染物电化学降解等具有优异的电催化活性而受到研究者的广泛关注,但DSA电极电催化现象背后的一些重要而基础性的问题仍未被人们完全认识。本文针对目前国内外有关DSA电极电催化研究领域中的几个研究热点、不足之处、以及尚待深入探究的问题,进行了简要介绍、分析和讨论。DSA电极的电催化活性主要是来自于其表面的金属氧化物涂层。本文强调对“氧化物涂层”自身固体物理-化学性能或过程的研究,有助于深入揭示钛基活性氧化物涂层电极电催化现象的微观作用机制和内在本质,并反过来指导人们更加理性地通过设计和优化DSA电极的制备方法和条件,调控表面氧化物涂层的化学组成与结构,进而达到增强钛基涂层电极电催化活性之目的。     

脉冲电沉积法制备Pt-TiO2 纳米管电极及其电催化性能

采用阳极氧化法在高纯钛片上原位组装TiO2纳米管阵列, 然后用脉冲电沉积方法将Pt沉积到TiO2纳米管阵列上, 制备出Pt-TiO2纳米管电极. 利用XRD和SEM对所获电极的微观结构和形貌进行表征, 结果表明, Pt纳米颗粒以花簇状分散在TiO2纳米管上, 晶粒大小约为25.6 nm. 对甲醇的电催化性能的研究结果表明, 脉冲电沉积制得的Pt-TiO2纳米管电极比TiO2纳米管电极和纯Pt片电极具有更高的电催化活性, 是Pt电极的40多倍.     

高阳极电势窗口的SnO2-Sb2O3/Ti电极的制备

制备了不同热处理温度和涂层次数的SnO2-Sb2O3/Ti电极,研究了不同电极涂层的氧化物组成,涂层表面形貌和阳极电势窗口及其三者的内在关系,考察了不同制备工艺条件的电极对电催化高铁性能的影响.结果表明430℃是电极最佳的热处理温度,涂层次数增加为30次时,电极具有高的阳极电势窗口,同时能降低高铁氧化还原反应的超电势,更真实的展现高铁电化学生成的热力学原貌.     

阳极电沉积Ti/MnO2电极及其苯酚降解的电催化性能

应用阳极电沉积法制备钛基二氧化锰(Ti/MnO2)电极. 采用X射线衍射(XRD)、扫描电子显微镜(SEM)及能谱（EDS）表征电极结构形貌. 用V~logi及苯酚降解实验优化电极制备工艺参数：在电流密度4 mA•cm-2、Mn2+离子浓度0.5 mol•L-1及温度70 ℃条件下阳极电沉积Ti/MnO2电极. 以苯酚为目标有机物,评价该电极电催化氧化性能,降解7h降解效率达49.6%.     

串联电脉冲沉积Co-Cr弥散Y2O3合金化微晶涂层

提出了一种利用被沉积基体材料作为感应电极，脉冲电源的输出两极均作为沉积电极的串脉冲沉积涂层技术，以Co30Cr合金为沉积电极，利用串联电脉冲沉积技术成功地在18－8不锈钢基体上沉积了Co-Cr合金化微晶涂层和弥散Y2O3细小颗粒的Co-Cr合金化微晶涂层，并在950℃静态空气中进行了涂层氧化试验。通过氧化动力学和SEM，XRD等分析表明，串联电脉冲沉积的合金化微晶涂层具有良好的抗高温氧化性能，同时也证实了在微晶涂层中施加细小的稀土元素氧化物颗粒有助于提高涂层的抗氧化性能和抗剥落性能。     

添加碳纳米管对钌铱锡氧化物阳极性能的影响

本文采用热分解法制备Ti/Ru-Ir-Sn氧化物阳极,运用TGA、SEM、EDS、循环伏安、电化学交流阻抗、极化曲线以及强化电解寿命测试方法,探讨添加不同含量碳纳米管（CNTs）对Ti/Ru-Ir-Sn氧化物阳极的影响规律. 热重分析和阳极能谱数据表明,在烧结温度470 ^oC条件下CNTs未发生高温氧化分解,仍以单质形式存在阳极涂层中. 与对比样品相比,涂层表面裂纹增多,但仍保持典型形貌. 添加CNTs显著改善了Ti/Ru-Ir-Sn氧化物阳极的电化学性能,增大了阳极的活性表面积,减小了涂层内部电阻,提高了阳极析氯电催化活性,析氯电位增加缓慢,阳极强化电解寿命也得到明显延长. 其中,添加0.1 g·L^-1 CNTs的Ti/Ru-Ir-Sn氧化物阳极电催化活性和稳定性最优.     

Ti/IrO_2-Ta_2O_5阳极载量与析氧电催化性能研究

采用Pechini法制得Ti/IrO2-Ta2O5氧化物阳极,研究了涂层载量对Ti/IrO2-Ta2O5阳极微观结构和析氧电催化性能的影响.SEM、EDX、极化曲线、循环伏安及强化电解试验等测试结果表明:涂层载量增加,涂层裂缝变窄变浅,且IrO2晶粒偏析趋于增强;同时也提高了阳极析氧电催化活性,增大阳极活性表面积及延长阳极使用寿命;强化电解寿命与Ir涂覆量(1.98～9.08g/m2)基本呈线性递增关系.     

WC颗粒改性钛基二氧化铅复合电极材料的电化学性能研究

为了提高锌电积用惰性阳极材料钛基二氧化铅的电催化活性和耐腐蚀性能,采用阳极氧化法制备了掺杂WC颗粒改性的钛基二氧化铅复合阳极材料。通过扫描电镜表征了电极材料的微观形貌,采用析氧极化曲线(LSV)、塔菲尔曲线和交流阻抗(EIS)研究WC添加量对复合阳极材料在电解锌液中的电催化性能和耐蚀性的影响。结果表明:WC与β-Pb O2复合电沉积能增强电极耐蚀性和电催化活性,当WC添加量为40 g/L时,所制备的复合电极材料结构致密,交换电流密度j0为6.71×10-3A·cm-2,电极自腐蚀电流密度Icorr为2.884×10-6A·cm-2,有较好的电催化活性和耐蚀性。     

金属氧化物涂层钛阳极的研究*

金属氧化物涂层钛阳极是指在以钛为阳极的基体表面涂上金属氧化物的电极,简称DSA。本文综述了钛基金属氧化物涂层电极的研究进展,包括钛基钌系涂层电极、钛基锡系涂层电极、钛基铅系涂层电极,以及其它氧化物涂层电极。评述了多元化钛基涂层的性能、各种涂层制备方法的优势与不足,阐明了掺杂稀土以及添加中间层对钛阳极的影响,同时展望了钛基金属氧化物涂层电极的发展方向。     

β-PbO2/TiO2纳米管电极的制备及其电催化降解苯酚

采用阳极氧化法和脉冲电沉积制备出β-PbO2改性TiO2纳米管(β-PbO2/TiO2-NTs)电极,通过扫描电子显微镜(SEM)、X射线衍射(XRD)和X射线光电子能谱(XPS)等技术手段对制备的β-PbO2/TiO2-NTs电极的表面形貌和结构进行了表征。结果表明,该方法成功地将β-PbO2纳米颗粒分散在TiO2纳米管中,通过电催化降解苯酚评价了β-PbO2/TiO2-NTs电极的电催化活性,实验结果表明,在TiO2-NTs中电沉积β-PbO2提高了电极的电催化活性,对苯酚的降解达到83%。     

Preparation and electrocatalytic property of lead dioxide prepared by pulse electrodeposition with different pulse current density

Lead dioxide electrodes were prepared by pulse electrodeposition in the lead nitrate solution with different pulse current density. The effects of pulse current density on the morphology and structure of lead dioxide electrodes were studied by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. The SEM and XRD results show that the increase of pulse current density can make the morphology more fine, and the crystal size of lead dioxide decreases with the increase of pulse current density. The anodic polarization curves demonstrate that the oxygen evolution overpotentials of lead dioxide electrodes also enhance with the increase of pulse current density. The stability of lead dioxide electrodes enhances with the increase of pulse current density until 15 mA cm^–2, then the stability decreases. The electrocatalytic property of lead dioxide electrodes was examined for the electrochemical oxidation of rhodamine B (RhB). The results show that the RhB removal efficiency on the lead dioxide electrodes increases with the increase of pulse current density, which can be attributed to the increase of oxygen evolution overpotential.     

电沉积纳米镍合金在海水溶液中的析氢性能

采用电沉积法获得Ni、Ni-Fe和Ni-Fe-C合金镀层电极, 在90 °C模拟海水(0.5 mol·L-1 NaCl, pH=12)的稳态极化曲线表明Ni-Fe-C合金电极具有最好的析氢催化性能. 通过扫描电子显微镜(SEM)观察电极表面形貌、X射线衍射(XRD)与透射电子显微镜(HRTEM)分析合金的晶体结构, 发现电极材料的晶粒尺寸影响析氢催化性能, 晶粒尺寸越小析氢催化活性越好. 用电化学阻抗方法(EIS)研究电极析氢催化性能的本质原因, 结果表明电极表面活性点数目和电极的本质电催化活性对合金电极析氢催化活性有重要的影响.     

Electrodeposited fabrication of highly ordered Pd nanowire arrays for alcohol electrooxidation

Highly ordered Pd nanowire arrays (NWAs) are prepared using a porous aluminum oxide template by pulse electrodeposition. The obtained Pd nanowire arrays with the diameter of 50 nm and length of 850 nm have been characterized by scanning electron microscopy, energy dispersive X-ray analysis, and high resolution transmission electron microscope. Meanwhile, the electrocatalytic activity of Pd NWAs electrodes for methanol and isopropanol oxidation in alkaline media is studied. It is found that the obtained nanostructures exhibit excellent catalytic activity for alcohol electrooxidation. The isopropanol oxidation shows the higher activity on Pd NWAs electrode than methanol in alkaline medium.     

Comparison of electrocatalytic characterization of Ti/Sb-SnO<Subscript>2</Subscript> and Ti/F-PbO<Subscript>2</Subscript> electrodes

Electrocatalytic oxidation is a promising process for degrading toxic and biorefractory organic pollutants in wastewater treatment. Selection of electrode materials is crucial for electrochemical oxidation process. In this study, Ti/F-PbO₂ and Ti/Sb-SnO₂ electrodes were chosen to compare their electrocatalytic characterization, which were prepared by electrodeposition and thermal decomposition method, respectively. The surface morphology and crystal structure of two electrodes were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The linear polarization curves show that Ti/Sb-SnO₂ electrodes possess higher oxygen evolution overpotential than Ti/F-PbO₂ electrodes. But the stability and corrosion resistance ability of Ti/F-PbO₂ electrode was higher than that of Ti/Sb-SnO₂ electrode. The electrocatalytic activity of Ti/F-PbO₂ and Ti/Sb-SnO₂ electrodes was examined for the electrochemical oxidation of malachite green (MG). The bulk electrolysis shows that the Ti/Sb-SnO₂ electrodes exhibit the higher electrocatalytic activity for the degradation of MG than Ti/F-PbO₂ electrodes, and the degradation process is good fitting for the pseudo-first order reaction. The higher electrocatalytic activity of Ti/Sb-SnO₂ electrodes can be attributed to the higher oxygen evolution overpotential.     

Two-layered Au@Ag Bimetallic Nanocomposites-poly (L-Met) Platform for Highly Sensitive Chlorpheniramine Maleate Detection

The two-layered bimetallic Au@Ag and poly(L-methionine) (Au@Ag/p-L-met) sensor was newly developed for the electrochemical determination of chlorpheniramine maleate (CPM). After electropolymerization of L-met, bimetallic surfaces were prepared by electrodeposition of Au@Ag nanoparticles on the p-L-met/PGE. The surface characterization was carried out by scanning electron microscopy (SEM), Energy Dispersive X-ray spectroscopy (EDX), Cyclic Voltammetry (CV) and Electrochemical impedance spectroscopy (EIS). The sensor shows good electrocatalytic activity, high sensitivity, wide linear range (0.87–600.0 μM) and a low detection limit (0.26 μM) by using Differential pulse voltammetry (DPV). The sensor was used to determine CPM in pharmaceutical samples with satisfactory results.     

Electrochemical deposition and characterization of NiCu coatings as cathode materials for hydrogen evolution reaction

In this study, NiCu composite coatings were electrochemically deposited on a copper electrode (Cu/NiCu) and characterized by atomic absorption spectroscopy (AAS), scanning electron microscopy (SEM) and scanning electrochemical microscopy (SECM) techniques in view of their possible applications as electrocatalytic materials for the hydrogen evolution reaction (HER). The HER activity of the prepared electrodes were studied in 1 M KOH solution by cathodic current–potential curves and electrochemical impedance spectroscopy (EIS) techniques. It was found that, the NiCu coating has a porous structure and good electrocatalytic activity for the HER in alkaline medium. The HER activity of the Cu/NiCu electrode was higher than uncoated (Cu) and Ni coated (Cu/Ni) copper electrodes. Its catalytic activity was related to the porosity as well as synergistic interaction of Ni and Cu.     

Glucose Electro‐oxidation on Graphite Electrode Modified with Nickel/Chromium Nanoparticles

In this study, an available and inexpensive graphite substrate, was easily modified with Ni/Cr nanoparticles via electrodeposition technique in a very short time (3 min) and used as an electrocatalyst for glucose oxidation in alkaline solution. Graphite electrode modified with Ni/Cr nanoparticles demonstrated an outstanding electrocatalytic performance to glucose oxidation in comparison to examined Ni‐based electrodes or even different materials in other reports. It is noteworthy to mention that adding a little Cr led to a synergistic effect with Ni; accordingly, the presence of Cr not only resulted in a greater adsorption of glucose molecules by chromium oxide but also boosted conductivity of the nickel oxide because of the enhancement of Ni(III) amount. The electrochemical studies were performed by cyclic voltammetry and electrochemical impedance spectroscopy (EIS). The morphology and structure of catalyst layer was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X‐ray diffraction (XRD) and energy dispersive x‐ray spectroscopy (EDS). The linear range of the electrode by cyclic voltammetry was between 2–31 mM with a high sensitivity of 2094 μA cm^?2 mM^?1. The repeatability and reproducibility of the proposed electrode was examined in glucose solution which were 0.3 % and 4.7 %, respectively. According to the low cost, ease and fast preparation, good repeatability and high sensitivity, this electrode can be a good candidate for nonenzymatic glucose oxidation.     

金属氧化物(Fe2O3, CuO,NiO)改性对TiO2纳米管阵列光电催化活性的增强效应

采用阳极氧化法和阴极电沉积法制备了Fe2O3,CuO和NiO纳米粒子改性的高度有序的TiO2纳米管(TiO2-NT)阵列.运用场发射扫描电子显微镜(FE-SEM),透射电子显微镜(TEM),X射线衍射(XRD)和紫外-可见漫反射光谱等手段对Fe2O3/TiO2-NT、CuO/TiO2-NT和NiO/TiO2-NT复合电极进行表征.以苯酚为模拟污染物,考察复合电极的光电性能.结果表明,金属氧化物(Fe2O3,CuO,NiO)纳米粒子成功沉积在TiO2-NTs的管口、内壁和管底.金属氧化物改性复合电极的光电催化活性比未改性的TiO2-NTs提高了2倍以上.Fe2O3/TiO2-NTs在可见光区显示出最高的吸收强度.以Fe2O3/TiO2-NTs为阳极处理苯酚废水,光照120min后苯酚去除率达到96%,而未改性的TiO2-NTs的苯酚去除率只有41%.此外,Fe2O3/TiO2-NTs在生成低毒中间产物方面表现出良好的性能.较高的复合电极光电催化活性主要是由于TiO2纳米管和过渡金属氧化物纳米粒子间构筑的高界面面积异质纳米结构,有效地促进了电子转移,抑制了光生电子-空穴对的复合.     

单极脉冲一步合成聚苯胺/铁氰化镍杂化膜及其过氧化氢电催化还原活性

采用单极脉冲法在铂基体表面一步合成聚苯胺/铁氰化镍 (PANI/NiHCF) 有机-无机杂化膜,并分析了杂化膜高电势静电吸引沉积机理. 高电压聚合杂化膜避免了Fe(CN)₆^3-的还原,并形成单一“不可溶”结构NiHCF. 用扫描电镜（SEM）、X射线能谱仪（EDS）和傅立叶变换红外（FT-IR）光谱研究了杂化膜表面形貌及组成,并考察了不同单极脉冲电压制得杂化膜的电化学性能. 结果表明,单极脉冲电压1.0 V制得的PANI/NiHCF杂化膜有最佳的电活性和良好的稳定性. 使用计时电流法考察了杂化膜电极的过氧化氢（H₂O₂）的电催化还原活性,在0.5 mol·L^-1 KCl + 0.5 mol·L^-1 HCl电解液中,PANI/NiHCF杂化膜电极过氧化氢催化还原电流与其浓度（4.0×10^-4 ~ 1.6×10^-2 mol·L^-1）呈良好的线性关系,相关性系数R = 0.9991,检出限为6.09×10-5 mol·L-1,灵敏度为1075 mA·(mol·L-1)-1·cm-2.     

Highly Active Nickel Nanoparticles Supported on TiO2 Nanotube Electrodes for Methanol Electrooxidation

Nickel nanoparticles/TiO₂ nanotubes/Ti electrodes were prepared by galvanic deposition of nickel nanoparticles on the TiO₂ nanotubes layer on titanium substrates. Titanium oxide nanotubes were fabricated by anodizing titanium foil in a DMSO fluoride‐containing electrolyte. The morphology and surface characteristics of titanium dioxide nanotubes and Ni/TiO₂/Ti electrodes were investigated using scanning electron microscopy and energy‐dispersive X‐ray spectroscopy, respectively. The results indicated that nickel nanoparticles were homogeneously deposited on the surface of TiO₂ nanotubes. The electrocatalytic behaviour of nickel nanoparticles/TiO₂/Ti electrodes for the methanol electrooxidation was studied by electrochemical impedance spectroscopy, cyclic voltammetry, differential pulse voltammetry and chronoamperometry methods. The results showed that Ni/TiO₂/Ti electrodes exhibit a considerably higher electrocatalytic activity toward the oxidation of methanol.