涂液浓度对Ru-Ti-Ir氧化物阳极涂层性能的影响

应用热分解法制备了由不同浓度涂液形成的Ru-Ti-Ir氧化物阳极涂层,SEM,EDX,XRD、强化电解寿命、极化曲线、循环伏安和电化学阻抗等测试表明,涂液浓度对阳极涂层的表面形貌有着很大的影响,但不甚影响其析氯极化过程.随着涂液浓度的增加,阳极涂层的伏安电量和双电层电容都出现先降低后增加的变化趋势.     

烧结温度对Ru-Ir-Sn氧化物阳极涂层性能的影响

应用溶胶凝胶法制备不同焙烧温度的氧化物阳极涂层,SEM,EDX,XRD、强化电解寿命、循环伏安和电化学阻抗等测试表明,烧结温度对阳极涂层的表面形貌以及电化学性能有着很大的影响.随着烧结温度的升高,析氯电位相应增加,寿命相对较长,循环伏安电量与双电层电容值有所下降.     

海水电解Ru-Ti-Ir-Sn氧化物阳极涂层研究

应用热分解法制备不同组分的Ru-Ti-Ir-Sn氧化物阳极涂层,并由SEM、EDX、强化电解寿命、电流效率、抗Mn2+污染、极化曲线和循环伏安等实验方法研究该Ru-Ti-Ir-Sn氧化物阳极涂层的物理性能和电化学性能.结果表明,优化配方的Ru-Ti-Ir-Sn氧化物阳极涂层对电解海水具有较好的综合性能.     

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.     

金属氧化物阳极失效过程的电化学监测

采用循环伏安和电化学阻抗谱等电化学方法对金属氧化物阳极在硫酸中的寿命加速过程进行了监测.检测了阳极伏安电量,双电层电容,氧化物膜电阻和析氧反应的电荷传递电阻等电化学参数随电解时间的变化,并提出金属氧化物阳极电解失效的机理.     

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.     

铱钽钛金属氧化物阳极的电化学特性

采用热分解方法在钛基体上制备铱钽钛金属氧化物阳极 ,用扫描电镜对阳极涂层显微形貌进行分析 ,通过强化电解寿命试验、开路电位测试、消耗率试验及循环伏安曲线研究了金属氧化物阳极的电化学性能 .SEM分析结果表明铱钽钛金属氧化物阳极涂层呈现多孔多裂纹形貌结构 .随阳极涂层组成不同 ,涂层显微形貌表现出很大差异 ,这种差异直接影响阳极电化学性能 .电化学性能试验结果表明铱钽钛金属氧化物阳极在酸性介质和海水中具有良好的电化学稳定性和电化学活性 .此外 ,铱钽钛金属氧化物阳极在海水中的消耗率很低 ,属于不溶性的阳极材料 ,作为外加电流阴极保护用辅助阳极具有广泛的应用前景 .     

Ru-Ir-Ti氧化物阳极正反电流电解失效机理研究

应用热分解法制备适用于海水电解的钛基金属氧化物阳极.由SEM、EDX和XRD分析表征该阳极的形貌、成分及相结构,结果表明,烧结后阳极表面形成了固溶体结构,分别为(Ru,Ir,Ti)O2和(Ir,Ti)O2,失效后氧化物阳极的固溶体结构几乎完全消失,活性物质丧失.强化正反向电流寿命测试、循环伏安曲线和电化学阻抗谱等测试表明,失效后氧化物阳极表面的电化学活性点大大减少,同时膜电阻增加,这是由于活性物质脱落导致的,进一步说明正反向电流导致阳极表面活性物质脱落是氧化物阳极失效的根本原因.     

SbOx+SnO2中间层对Ti/MnO2电极性能的影响

采用热分解方法制备了含SbO_x+SnO₂中间层的钛基二氧化锰电极. 在0.5 mol·L^-1 H₂SO₄溶液中对添加和没有添加SbO_x+SnO₂中间层的二氧化锰阳极进行了加速电解试验. 采用极化曲线和循环伏安曲线测量电极的析氯反应. 用循环伏安曲线和电化学阻抗谱来分析电极电解过程中内部结构和表面的变化. 结果表明, 二氧化锰阳极钝化失效的主要原因是绝缘的TiO₂层的生成和变厚. 引入中间层可以降低钛基体和活性涂层间的电阻, 并且在电解过程中, 可以显著延缓接触电阻的升高, 从而可以显著提高其寿命.     

添加Sn组元对Ru-Ti-Ir阳极涂层的改性研究

应用热分解法制备不同Sn含量的Ru-Ti-Ir-Sn氧化物阳极涂层,SEM、EDX、XRD、析氯电位、电流效率及循环伏安和电化学阻抗谱等实验表明,Ru-Ti-Ir经添加Sn组元后,该阳极涂层表面形貌发生了很大变化,Sn组元的添加不仅有利于该阳极涂层析氯电位的降低,而且能够有效提高其电流效率.     

Low Pt content Pt–Ru–Ir–Sn quaternary catalysts for anodic methanol oxidation in DMFC

In this communication we report our research work on low Pt content Pt–Ru–Ir–Sn quaternary catalysts for use in DMFC anodes. The carbon-supported quaternary metal alloy catalyst was synthesized according to the solution reduction method and was deposited onto a carbon fiber paper or a carbon aerogel nanofoam to form the anode for direct methanol fuel cells. The Pt loading of the electrode is 0.1 mg/cm². The testing results from a three-electrode electrochemical cell show that the simultaneous use of higher Ir (25–35 wt.%) and Sn (10 wt.%) content gives satisfactory stability and higher activity for methanol oxidation than the commercially available E-TEK anode (80%[0.5Pt 0.5Ru]/C on carbon cloth). Energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), scanning electron microscope (SEM), and Bruner–Emmett–Teller method (BET) measurements were carried out to characterize the composition, structure, morphology, and surface area of the developed catalysts.     

Microstructural impact of anodic coatings on the electrochemical chlorine evolution reaction

Sol-gel Ru(0.3)Sn(0.7)O(2) electrode coatings with crack-free and mud-crack surface morphology deposited onto a Ti-substrate are prepared for a comparative investigation of the microstructural effect on the electrochemical activity for Cl(2) production and the Cl(2) bubble evolution behaviour. For comparison, a state-of-the-art mud-crack commercial Ru(0.3)Ti(0.7)O(2) coating is used. The compact coating is potentially durable over a long term compared to the mud-crack coating due to the reduced penetration of the electrolyte. Ti L-edge X-ray absorption spectroscopy confirms that a TiO(x) interlayer is formed between the mud-crack Ru(0.3)Sn(0.7)O(2) coating and the underlying Ti-substrate due to the attack of the electrolyte. Meanwhile, the compact coating shows enhanced activity in comparison to the commercial coating, benefiting from the nanoparticle-nanoporosity architecture. The dependence of the overall electrode polarization behaviour on the local activity and the bubble evolution behaviour for the Ru(0.3)Sn(0.7)O(2) coatings with different surface microstructure are evaluated by means of scanning electrochemical microscopy and microscopic bubble imaging.     

Sn改性的Ru/H-CMK-3催化剂的制备及其肉桂醛选择性加氢性能的研究

用浸渍-原位还原法制备了Ru-Sn/H-CMK-3催化剂. 以肉桂醛选择性加氢制备肉桂醇为探针反应. 详细研究了催化剂的制备及反应条件对肉桂醛选择性加氢性能的影响. 采用X 射线粉末衍射(XRD)、比表面积(BET)、X光电子能谱(XPS)、透射电镜(TEM)等手段对催化剂结构和性质进行了表征. 结果表明, 介孔CMK-3碳材料能够更好地分散活性物种. 添加适量的Sn(IV)有利于Ru处于电子富集状态. 催化剂的主要活性物种是纳米Ru粒子, Ru和Sn之间的相互作用更加有利于C＝O的活化. 同时, 反应温度和反应压力等条件的变化对肉桂醛选择性加氢制备肉桂醇反应也具有较大的影响.     

Corrosion and electrochemical behavior of metal-oxide anodes during electrolysis with an ion-exchange membrane

The reasons for a specific behavior of anodes in chlorine electrolysis with an ion-exchange membrane are considered. The corrosion rate in modeling conditions and the predicted lifetime of anodes of different compositions are studied. The anodes’ coatings contain mixed oxides of Ir, Ru, Sn, or Ti. The effect of the anode’s position relative to the membrane and a relative stability of the anode coatings are examined in conditions simulating a heavy alkalization of the anolyte caused by a membrane rupture. A considerable advantage of using the anode with a coating containing 15, 15, and 70 mol % of RuO₂, IrO₂, and TiO₂ is demonstrated     

Combinatorial discovery of new methanol-tolerant non-noble metal cathode electrocatalysts for direct methanol fuel cells

Combinatorial synthesis and screening were used to identify methanol-tolerant non-platinum cathode electrocatalysts for use in direct methanol fuel cells (DMFCs). Oxygen reduction consumes protons at the surface of DMFC cathode catalysts. In combinatorial screening, this pH change allows one to differentiate active catalysts using fluorescent acid-base indicators. Combinatorial libraries of carbon-supported catalyst compositions containing Ru, Mo, W, Sn, and Se were screened. Ternary and quaternary compositions containing Ru, Sn, Mo, Se were more active than the "standard" Alonso-Vante catalyst, Ru(3)Mo(0.08)Se(2), when tested in liquid-feed DMFCs. Physical characterization of the most active catalysts by powder X-ray diffraction, gas adsorption, and X-ray photoelectron spectroscopy revealed that the predominant crystalline phase was hexagonal close-packed (hcp) ruthenium, and showed a surface mostly covered with oxide. The best new catalyst, Ru(7.0)Sn(1.0)Se(1.0), was significantly more active than Ru(3)Se(2)Mo(0.08), even though the latter contained smaller particles.     

An infrared study of CO adsorption on silica-supported Ru-Sn catalysts

CO adsorption on Ru-Sn/SiO(2) catalysts of various Sn/(Ru+Sn) ratios was examined by Diffuse Reflectance Infrared Fourier-Transform Spectroscopy (DRIFTS). The catalysts were prepared by the incipient wetness impregnation method. Catalysts were activated by H(2) reduction at 773 K. CO adsorbed on the catalysts shows spectra whose band frequencies are divided into three groups: (i) High Frequency Region (HFR), containing a band at 2065 cm(-1), (ii) Low Frequency Region 1 (LFR(1)), containing bands at 2040-2015 cm(-1), (iii) Low Frequency Region 2 (LFR(2)), containing bands at 1990 and 1945 cm(-1). The types of adsorbed CO species formed strongly depend on the ratio Sn/(Ru+Sn) in the catalyst, CO pressure and temperature of adsorption. Adsorption of CO on Ru sites in the Ru/SiO(2) catalyst results in LFR(1) bands at 2040-2015 cm(-1), which are independent of the CO pressure but the adsorption complexes are easily destroyed by raising the temperature. The addition of Sn to the catalyst creates new sites for CO adsorption. After adsorption at 298 K, the HFR band at 2065 cm(-1) and LFR(2) bands at 1990-1950 cm(-1) are observed. The relative intensities of these bands increase with increasing Sn-content in the samples. The LFR bands are thermally stable while the HFR band is not. The formation of the corresponding species is favored by increasing the CO pressure. Adsorbed CO species giving LFR(1) bands are assigned to linearly-adsorbed CO on the Ru(0) and/or on the Ru-Sn alloy sites. Adsorbed CO species giving HFR bands are assigned to CO adsorption on Ru(delta+)-O-Sn sites. After low temperature CO adsorption on samples with high Sn-content, only species that show bands at 1990 and 1945 cm(-1) in LFR(2) are observed.     

Ti/Ru0.1Ti0.1Sn0.8O2电极电容性能研究

低温热分解法制备Ti/Ru0.1Ti0.1Sn0.8O2.XRD表征该样品结构特性,循环伏安和恒流充放电测定电极性能.结果表明,Ti/Ru0.1Ti0.1Sn0.8O2物相属细小的金红石相,在20 mV/s扫速下该电极比电容达933F/g.1000次充放电循环后,比电容衰减23.6﹪,显示良好的循环稳定性和可逆性.