SiO2含量对Ti/IrO2-Ta2O5-SiO2析氧阳极的电催化活性及稳定性的影响

以钛板为基体,通过热分解H2IrCl6,TaCl5和H2SiO3的混合涂液制备了Ti/IrO2-Ta2O5-SiO2阳极,研究了SiO2含量对Ti/IrO2-Ta2O5-SiO2阳极电催化活性及稳定性的影响.结果表明:掺杂SiO2后Ti/IrO2-Ta2O5-SiO2阳极电催化活性降低;适量SiO2可以提高Ti/IrO...     

有机添加剂对Ru0.5Ir0.5O2/Ti电极性能的影响

通过向溶胶凝胶制备体系中加入有机添加剂四乙基氢氧化铵(TEAOH)、四丙基溴化铵(TPABr)和十六烷基三甲基溴化铵(CTAB)制备了Ru0.5Ir0.5O2钛基涂层阳极.采用扫描电镜(SEM)、循环伏安法、极化曲线和强化寿命测试研究了电极的微观结构、电化学性能和稳定性.结果发现,加入TEAOH可显著增大涂层的真实表面积和减小电极的极化程度,从而大大提高电极的电催化活性,同时保持了电极的高稳定性.     

Oxidation of p-methoxyphenol on SnO2–Sb2O5 electrodes: Effects of electrode potential and concentration on the mineralization efficiency

The oxidation of p-methoxyphenol in aqueous solution on antimony-doped tin oxide has been studied, and the effects of applied potential and initial PMP concentration upon the oxidation rate have been identified. The concentration decay of PMP during its electrooxidation follows first-order reaction kinetics. Analysis solution during electrolysis using UV–Vis spectroscopy revealed that under some experimental conditions partial oxidation of PMP occurs. The principal products were p-benzoquinone and aliphatic (maleic and oxalic) acids. The Faradaic efficiencies for oxidation at different applied potentials were determined from the UV–Vis spectra obtained. It is shown that production of CO₂ was very low at potentials below 2.3 V with respect to the saturated calomel electrode, and that at more positive potentials mineralization to CO₂ decreased as the concentration of PMP in solution increased.     

Decolorization of Methyl Orange Dye at IrO2‐SnO2‐Sb2O5 Coated Titanium Anodes

A film of iridium and tin dioxides doped with antimony oxide (IrO₂‐SnO₂‐Sb₂O₅) was deposited onto Ti mesh and plate substrates by the Pechini method. The electrode surface morphology and composition were characterized by SEM‐EDS. The ternary oxide coating was used for the anodic oxidation of methyl orange (MO) azo dye. Linear sweep voltammetry was used to identify the electrode potentials that favour MO degradation. Batch electrolyses were then carried out at a constant electrode potential of 1.5, 1.75 and 2.0 V vs. SHE using either a three‐electrode batch cell or a flow reactor. The dye solutions were totally decolorized via reactive oxygen species, such as ^?OH, H₂O₂ and O₃ formed in situ from water oxidation at the Ti/IrO₂‐SnO₂‐Sb₂O₅ surface.     

钛基锡锑氧化物电极在合成偶氮二甲酰胺中的应用

采用热分解法制备的SnO2+Sb2O3/Ti作为阳极材料,以联二脲为原料,电化学氧化法合成出偶氮二甲酰胺。通过单因素实验和正交实验研究了电流密度、电量、NaBr的质量浓度和H2SO4的浓度以及反应温度对偶氮二甲酰胺的产率和电流效率的影响。得出最佳工艺条件:电流密度2 300 A/m2,电量12 350 C,NaBr的质量浓度和H2SO4的浓度分别为8 g/L和1.47 mol/L,温度40℃。在最佳条件下,偶氮二甲酰胺的产率达94%,质量分数97%,电流效率89%。此外,SnO2+Sb2O3/Ti电极在NaBr和H2SO4的溶液中的循环伏安测试结果表明,吸附溴原子Brad复合成溴的步骤控制电合成偶氮二甲酰胺的反应速度。整个电极过程包括电子转移及后续的化学反应(EC机理)。     

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.     

Preparation and electrochemical performance of uniform RuO2/Ti and RuO2‐IrO2/Ti electrode for electrolysis of NaCl solution

The electrochemical preparation of NaClO has been widely used for the production of industrial disinfectant. To reduce the cost of electrode preparation using the brushing method, this paper introduces a method for the electrodeposition for RuO₂/Ti and RuO₂‐IrO₂/Ti preparation and NaCl solution electrolysis. The deposition of Ir improves the uniformity and stability of the RuO₂/Ti electrode. The optimum preparation conditions and additive concentrations were investigated in detail through the orthogonal experiment. By adjusting the electroplating time, temperature and voltage, the electrode with a high content of available chlorine was synthesized successfully. The physicochemical properties of the as‐prepared RuO₂/Ti and RuO₂‐IrO₂/Ti were determined by XRD, SEM‐EDS, and XPS, and the electrochemical performance and lifetime of the RuO₂/Ti and RuO₂‐IrO₂/Ti was verified via an electrochemical workstation. Uniform and stable RuO₂/TiO₂ and RuO₂‐IrO₂/TiO₂ were synthesized successfully for the electrolysis of the NaCl solution.     

Ti/SnO2+Sb2O3/PbO2电极在硫酸溶液中Cr3+氧化的电化学性能

对用聚合前驱体溶液通过热分解法制备的Ti/SnO2+Sb2O3/PbO2电极在硫酸溶液中Cr3+电化学氧化的电化学性能进行了研究. 分别测定了以Ti/SnO2+Sb2O3/PbO2和PbO2为阳极，硫酸介质中Cr3+电化学氧化过程的极化曲线、抗腐蚀性以及不同操作电流密度、Cr3+浓度、反应温度、硫酸浓度下的电流效率. 实验结果表明，聚合前驱体溶液通过热分解法制备的Ti/SnO2+Sb2O3/PbO2电极与PbO2电极相比具有更高的电催化活性和抗腐蚀性.     

Ti/IrO2+MnO2电极在酸性溶液中的电化学活性表面积

采用涂覆热分解法制备不同成分的Ti/IrO₂+MnO₂电极,利用恒电位循环伏安法研究Ti/IrO₂-MnO₂电极在硫酸溶液中的电化学表面行为,并用直线外推法定量地评价电极的电化学活性表面积。结果表明,Ti/(0.7)IrO₂+(0.3)MnO₂的伏安电荷达到最高,为电化学活性表面积最大;随着电位扫描速率增大,伏安电流密度不断增加,而伏安电荷容量逐渐减少,直到维持恒定;所有Ti/IrO₂+MnO₂电极的“内部”电化学活性表面积远大于“外部”电化学活性表面积,约为“外部”电化学活性表面积的2倍,说明电极内部存在丰富的多孔结构,真实表面积巨大,因此Ir⁴⁺/Ir³⁺转化反应多发生于内电化学活性表面区域。     

Effect of composition on the surface and electrocatalytic properties of Ti/IrO x +RhO x electrodes: H2 evolution from acidic solution

IrO _x +RhO _x mixed oxide layers on a Ti support were prepared by thermal decomposition at 450 °C over the whole composition range. The temperature range 450–600 °C was explored for the composition 30 mol% RhO _x . Samples were characterized by means of SEM, XPS, cyclic voltammetry and polarization curves. Their electrocatalytic properties were tested for the H₂ evolution reaction. The following experimental parameters were scrutinized: voltammetric charge, Tafel slope, reaction order (H⁺), electrical resistance of electrocatalysts. The electrocatalytic properties were evaluated at constant potential as a function of temperature as well as of composition. The electrode stability was assessed by comparing CV curves before and after groups of experiments. A reaction mechanism has been proposed. RhO _x is more active than IrO _x , its effect showing up for compositions >30 mol%. In honour of Professor G. Kreysa on the occasion of his 60th birthday. On leave from Institute for Nuclear Research, Pitesti, Romania.     

Effect of hydrothermal treatment on the performance of RuO2-Ta2O5/Ti electrodes for use in supercapacitors

Hydrothermal treatment (HTT) of RuO₂-Ta₂O₅/Ti electrode, as a method for improving their performance, for use in supercapacitors was investigated.The results show that HTT significantly enhances the stability of the electrodes. The specific capacitance of electrodes, subject to HTT in the temperature range 180-250 °C remains unchanged after 1000 CV cycles between −0.2 and 1.1 V vs. SCE; without HTT a decay to 97% of the initial is observed. The results also show that HTT decreases the activity of the electrodes for O₂ and H₂ evolution and increases the voltage window by 56-135 mV for supercapacitors, but with a specific capacitance decrease of 7-27%. XPS analyses show the existence of more hydroxides after the HTT, which leads to a little increase in the interplanar distance as indicated in the XDR results. Contact angle measurements show the presence of a more hydrophilic surface after HTT.     

Electrochemical properties of Ti/SnO2-Sb2O5 electrodes prepared by the spray pyrolysis technique

Cyclic voltammetry for the ferri-ferrocyanide redox couple has been used to study the Ti/SnO₂-Sb₂O₅ electrode prepared by spray-pyrolysis under different conditions. The obtained results shows that increasing the preparation temperature and the duration of coating deposition results in a decrease of i _p and an increase of E _p for the ferri-ferrocyanide couple. This deviation from reversibility has been attributed to the formation of a titanium oxide layer at the Ti/coating interface. Concerning oxygen evolution at the Ti/SnO₂-Sb₂O₅ anodes, a mechanism is proposed in which water is discharged at the anode forming hydroxyl radicals which are further oxidized to form dioxygen. Finally, a generalized mechanism for oxygen evolution at oxide electrodes has been proposed.     

钛基金属氧化物涂层电极的研究进展

钛基金属氧化物涂层电极又称DSA,是一种新型不溶性阳极电极。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、钛基铱系涂层电极、钛基二氧化锰电极和钛基二氧化铅电极。介绍了不同钛基涂层电极材料的制备方法、性能特点和应用情况,并对其今后的发展方向作了展望。     

高铁酸钠在二氧化锡-三氧化二锑/钛电极上的电化学行为研究

采用优化热处理温度的二氧化锡-三氧化二锑／钛电极和循环伏安法，研究了不同温度时高铁酸钠的电化学行为，得到相应的电化学参数。实验表明电极优化后能有效降低FeO4^2-/FeO2^-体系氧化还原反应的超电势，具有良好的电催化性能，反应表观活化能为25．53kJ／mol,铁（V）是FeO4^2-／FeO2^-体系的中间态物种，容易快速歧化生成铁（Ⅵ）和铁（Ⅲ）。     

铱钛氧化物中间层对钛基氧化铱电极组织及析氧行为的影响

以纳米TiN粉体和氯铱酸的混合液为涂液,采用浸渍一热分解法制备了含IrOx-TiO2中间层的钛基氧化铱电极.研究了IrOx-TiO2中间层对钛基氧化铱电极的显微结构及析氧寿命的影响.结果表明,TiN作为前驱体氧化生成金红石相的二氧化钛与氧化铱形成固溶体,并与钛基体形成了共格界面,从而构成了铱钛复合氧化物中间层,中间层的加入没有改变传统钛基氧化铱电极的基本形貌特征和组成,因而具有相同的电催化响应特性;由于中间层中二氧化钛的固溶和与钛基体的共格结合起到机械和化学的双重作用,电极的析氧寿命明显延长,从而通过实验手段证明了氧化铱电极失效的主要机制是由于钛基界面的劣化引起的.     

High‐temperature stability of YSZ and MSZ ceramic materials in CaF2–MgF2–MgO molten salt system

The high‐temperature stability of YSZ and MSZ specimens was investigated in CaF₂–MgF₂–MgO molten salt at 1200°C. YSZ was mostly composed of m‐ZrO₂ and a small part of YF₃ in the early stages. The formation of YF₃ was attributed to the chemical reaction between Y₂O₃ and MgF₂, which can lead to the leaching of Y₂O₃ from YSZ. With an increase in exposure time, the degraded surface was coarser, and considerable amount of cracks, pores, and spallations were formed. Furthermore, no Y₂O₃ was found up to 120 μm of the YSZ bulk in the early stages. MSZ was composed of t‐ZrO₂ after 24 hours. However, the volume fraction of m‐ZrO₂ was 72% after 72 hours, and CaZrO₃ was formed by the chemical reaction between CaO and ZrO₂ after 168 hours. In addition, the volume fraction of m‐ZrO₂ was 60% in 2.5 wt% MgO and 49% in 10 wt% MgO. In 5 wt% MgO, CaZrO₃ was formed. We demonstrate that the high‐temperature stability of MSZ was better than that of YSZ, and that 10 wt% MgO was much more stable than the other concentrations of MgO.     

The effect of SiO2 on electrical properties of low‐temperature‐sintered ZnO–Bi2O3–TiO2–Co2O3–MnO2‐based ceramics

ZnO–Bi₂O₃–TiO₂–Co₂O₃–MnO₂‐based (ZBTCM) varistors were fabricated via the conventional solid‐state method, and the effect of SiO₂ content on the phase transformation, microstructure, and electrical properties of the ZBTCM had been investigated. Results showed that this varistor can be sintered at a low temperature of 880°C with a high sintering density above 0.95 of the ZnO theoretical density. In these components, SiO₂ acts as a controller in ZnO grain growth, decreasing the grain size of ZnO from 3.67 to 1.92 μm, which in turn results in an increase in breakdown voltage E_1mA from 358.11 to 1080 V/mm. On the other hand, SiO₂ has a significant influence on the defect structure and component distribution at grain‐boundary regions. When SiO₂ content increases from 0 to 4 wt%, the value of the interface state density (N_s) increases sharply. At the same time, the electrical properties are improved gradually, and reach an optimized value with the nonlinear coefficient (α) up to 54.18, the barrier height (?_b) up to 2.90 eV, and the leakage current (I_L) down to 0.193 μA/cm².     

Electrochemical and morphological properties of Ti/Ru0.3Pb(0.7−x)TixO2-coated electrodes

In this work, a ternary coating with the nominal composition Ti/Ru_0.3Pb_(0.7−x)Ti_xO₂ (0≤x≤0.7) deposited on Ti has been prepared through thermal decomposition of ruthenium, titanium and lead inorganic salts dissolved in isopropanol. To find out coatings with reasonable service life for application in electrolysis devices, changes in the firing temperature, heating time and supporting electrolyte have been investigated. Surface morphology and microstructure have been investigated by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). SEM data show that the mud-crack structure is progressively lost with the substitution of titanium by lead oxides. EDS results suggest that lead segregates, forming islands with a high content of Pb. Changes in crystallinity have been obtained with an increase in the lead content. Electrochemical analyses have been carried out in acid medium (HClO₄ 1.0 mol dm⁻³ and H₂SO₄ 0.5 mol dm⁻³). Cyclic voltammetric data and quasi-steady-state polarization curves have been recorded and accelerated life tests have been performed with an anodic current of 400 mA cm⁻². High coating stability has been obtained with the electrode fired at 550 °C. Replacing Ti with Pb extends the service life and improves the catalytic activity for oxygen evolution reaction (OER).