LSGMC5含量对于二甲醚燃料电池复合Ni-Fe阳极性能的影响

用浸渍法制备了掺杂不同质量分数的La0.8Sr0.2Ga0.8Mg0.15Co0.05O3-δ (LSGMC5)粉末的Ni8-Fe2-LSGMC5复合阳极, 并采用交流阻抗和直流极化技术考察了以氢气和二甲醚为燃气时该复合阳极的电化学性能及相应电池的功率输出特性. 结果表明, 在电极中掺入LSGMC5 粉末, 能显著地改善电极的形貌和电极/电解质界面结构, 减小欧姆电阻和极化电阻. 电极中LSGMC5 粉末含量对于氢气及二甲醚电化学氧化性能的影响显著不同. 以二甲醚为燃气时, 电极极化电阻随LSGMC5 粉末含量的增加而减小, 其中LSGMC5 掺杂量为30%的复合阳极具有最高的电化学性能, 相应电池在1073、1023、973 K 时的输出功率分别为1.00、0.61、0.40 W·cm-2; 以氢气为燃气时, LSGMC5 掺杂量为20%的复合阳极具有最好的电化学性能, 随着LSGMC5 掺杂量的进一步增加, 电极极化电阻显著增大.     

新型的钛基Ni-Sn/Ti电极的制备及对甲醇氧化反应的电催化活性

利用电热法,一步制备出新型的钛基Ni-Sn/Ti电极(Ni8Sn/Ti, Ni7Sn3/Ti 和 Ni/Ti)。扫描电镜（SEM）图像表明,催化剂以片状的纳米颗粒形式沉积于钛基体上。利用电化学伏安技术、电位阶跃法和电化学交流阻抗谱（EIS）,研究了这些电极在1mol.L�1NaOH溶液中对甲醇氧化反应的电催化活性。研究表明,与Ni7Sn3/Ti,Ni/Ti以及多晶镍电极相比,Ni8Sn/Ti电极对甲醇氧化反应表现出更高的阳极氧化电流和更低的起始电位。EIS分析表明,在本文所考察的阳极电位和甲醇浓度下,Ni8Sn/Ti电极对甲醇氧化反应显示出极低的电荷传递电阻。结果表明,这种新型的钛基Ni8Sn/Ti电极对甲醇氧化反应具有极高的电催化活性。     

中温天然气燃料电池复合阳极NiO-La0.75Sr0.25Cr0.5Mn0.5O3-δ-Ce0.8Sm0.2O2-δ的制备和性能研究

采用共压-共烧结的方法制备了以NiO-La0.75Sr0.25Cr0.5Mn0.5O3-δ-Ce0.8Sm0.2O2-δ复合阳极为支撑、以Ce0.8Gd0.2O2-δ(GDC)为电解质、以La0.8Sr0.2Co0.8Fe0.2O3-δ(LSCF)-Ce0.8Gd0.2O2-δ(GDC)为复合阴极的单电池,在400～700 ℃范围内,以加湿天然气(3%H2O)为燃料气,氧气为氧化气,测试了电池的放电性能.利用XRD、SEM、EDX等手段对复合阳极进行结构、化学相容性、微观型貌和碳元素分析.分析结果表明,符合阳极具有较好的化学相容性,且阳极和阴极具有较好的孔隙、孔道结构.EDX测试结果表明有少量的碳沉积.在600℃进行了电池的稳定性测试.测试结果表明,该电池在13 h的测试过程中功率无明显衰减,具有较好的稳定性.复合阳极单电池在600℃得到最大电流密度,为215.49 mA·cm-2;最大功率流密度为44.85 mW·cm-2.     

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。     

LiV_3O_8电极在硫酸锂-水-乙醇电解质中的电化学性能研究(英文)

应用低温液相反应再经450℃中温锻烧制备LiV3O8活性物质,并用X射线衍射(XRD)分析和扫描电镜(SEM)表征了产物LiV3O8结构、形貌.电化学方法研究LiV3O8电极在硫酸锂-水-乙醇中性电解质溶液中的性能.恒流充放电结果表明,LiV3O8电极的比容量随电解质溶液中乙醇含量的增加而降低,若同时考虑电解质溶液的电导率和电极的稳定性,水/乙醇体积比4∶1最为合适.交流阻抗测试表明,溶液的欧姆电阻以及电极/电解质界面的电荷转移电阻随溶液中乙醇含量的增加而增大;随着充放电循环的进行,电极/电解质界面的电荷转移电阻增大,电极的活性降低.     

用于电催化氧化甲醛的新型Ni(OH)2-X/CPE负载电极的制备

采用一种简易的方法制备了新型Ni(OH)2-X/CPE电极,并将其用于电催化氧化甲醛反应.采用扫描电镜和能量散射谱对所制Ni(OH)2-X/CPE电极进行了表征,并运用循环伏安法、电化学阻抗谱和计时电流法考察了该电极的电化学性能.结果表明,该Ni(OH)2-X/CPE电极对甲醛氧化表现出高电催化活性,这归功于X具有纳米孔结构和大的比表面积.电子传递系数和催化反应速率常数分别为0.7和6.1×104 cm3/(mol·s).该电极对甲醛氧化具有高而稳定的电催化活性,且制备重复性高,有望应用于燃料电池中.     

应用扫描电化学显微镜研究极化液/液界面上的电子转移反应

将含有氧化还原电对的水溶液滴涂在铂盘电极表面, 然后将该电极插入到1,2-二氯乙烷溶液中, 形成稳定的油/水界面. 液滴中的K3Fe(CN)6和K4Fe(CN)6氧化还原电对既可以作为水相中的参比电对参与控制液/液界面上的电势差, 同时又可以作为水相的电子授受体参与界面上的电子转移反应. 结合扫描电化学显微镜电化学系统的特点, 利用其双恒电位仪分别控制界面电势差和现场扫描的优点, 通过扫描电化学显微镜的渐进曲线得到了不同界面电势差控制的电子转移反应速率常数. 实验结果表明, 应用此方法获得的液/液界面可以被外加电位极化, 在一定的电势差范围内, 反应速率常数与界面电势差的关系遵守Butler-Volmer公式.     

苯并噻唑和铁氧化物纳米粒子修饰的磁性棒碳糊电极上肼的电催化氧化反应：同时检测肼和苯酚

开发了一种磁性Fe3O4纳米粒子和2-(3,4-二羟苯基)苯并噻唑(DPB)修饰的磁性棒碳糊电极(MBCPE)用于电化学检测肼.首先将DPB自组装在Fe3O4纳米粒子上,然后将此复合物吸附于设计的MBCPE上. MBCPE电极将磁性纳米粒子吸引到电极表面.所得新型电极具有高的导电性和大的有效比表面积,因而对肼的电催化氧化反应有非常大的电流响应.采用伏安法、扫描电镜、电化学阻抗谱、红外光谱和紫外-可见光谱对修饰电极进行了表征.采用伏安法研究了在磷酸盐缓冲溶液(pH=7.0)中MBCPE/Fe3O4NPs/DPB电极上肼的电化学行为.作为电化学传感器, MBCPE/Fe3O4NPs/DPB电极对肼氧化反应表现出极高的电催化活性.在DPB存在下,肼的氧化电势下降,但其催化电流增加.电催化电流与肼浓度在0.1–0.4和0.7–12.0μmol/L二个区间内表现出线性关系,检测限为18.0 nmol/L.另外,研究了MBCPE/Fe3O4NPs/DPB电极同时检测肼和苯酚的性能.伏安实验结果显示,苯酚的线性区域为100–470μmol/L,检测限为24.3μmol/L.采用此电极检测了水样品中的肼和苯酚.     

固体氧化物燃料电池用（La，Sr）（Co，Fe）O3-δ阴极的制备及其电化学催化性能

采用溶液注入法和丝网印刷法制备了(La,Sr)(Co,Fe)O3-δ (LSCF)/YSZ与LSCF/GDC复合电极,并通过扫描电镜和电化学阻抗谱研究了不同结构电极的微观形貌和电化学催化性能. 结果表明, LSCF阴极与YSZ电解质在低于800 ℃下制备时,没有新相产生; 在中温固体氧化物燃料电池的工作条件(700～750 ℃)下,溶液注入法制备的LSCF阴极与YSZ电解质有较好的化学相容性和较高的电化学催化活性,而丝网印刷法制备的LSCF阴极则表现出稳定的电化学催化性能.     

利用钐掺杂的氧化铈夹层提高燃料电池阳极的活性

考察了Ni-钐掺杂的氧化铈(Ni-SDC)复合阳极与La0.9Sr0.1Ga0.8Mg0.2O3(LSGM)电解质中间加入的SDC 中间层对阳极及整个电池性能的影响.结果表明，SDC中间层的加入显著减小了阳极极化过电位，但同时引入了欧姆降，降低了电池的功率输出密度.氢在Ni-SDC电极的氧化主要由两个过程控制，分别对应于交流阻抗谱的两个阻抗半圆，高频环随着SDC中间层的加入显著减小，可能对应于H2在Ni-SDC/SDC/H2三相界的电化学氧化或氧从LSGM向SDC的传输，低频环与SDC中间层无关，可能对应于氢在电极表面的解离吸附及吸附物种的扩散过程.使用Ni-SDC/SDC夹层阳极可以明显地提高电池的稳定性.     

Ni-Fe/Ti和Ni-Fe-S/Ti的制备及其电催化水分解性能

以钛网为基底,采用电沉积法制备了Ni-Fe/Ti析氧电极,然后将得到的Ni-Fe/Ti电极通过固相硫化制备了Ni-Fe-S/Ti析氢电极. 分别考察了电沉积液中Ni ²⁺/Fe ³⁺离子摩尔浓度比和硫脲加入量对Ni-Fe/Ti和Ni-Fe-S/Ti结构和电化学性能的影响. 结果表明,随着电沉积液中Ni ²⁺含量的增加,Ni-Fe/Ti电极析氧性能先增强后减弱,Ni9Fe1/Ti电极具有最好的析氧性能;随着硫脲加入量的增加,Ni-Fe-S/Ti电极析氢性能呈现先增强后减弱的趋势,Ni9Fe1S0.25/Ti电极具有最好的析氢性能. 在50 mA·cm ^-2下,Ni9Fe1/Ti电极的析氧过电位为280 mV,Ni9Fe1S0.25/Ti电极的析氢过电位为269 mV,且均具有很好的稳定性. 将Ni9Fe1/Ti与Ni9Fe1S0.25/Ti分别作为阳极和阴极进行电催化全水分解,电流密度达到50 mA·cm ^-2所需电势仅1.69 V,表现出很好的全水解催化性能.     

Electrochemical behavior of nickel in electrolytes based on 1-n-butyl-3-methylimidazolium tetrafluoroborate ionic liquid for capacitor applications

Electrochemical studies were performed using Ni electrodes in solutions of a mixture of ethylene glycol or of γ-butyrolactone with 1-n-butyl-3-methylimidazolium tetrafluoroborate ionic liquid. The aim of the study was to evaluate the use of these systems in electrochemical double-layer capacitor. Cyclic voltammetry experiments showed a potential range at which the Ni electrode behaved as a polarizable electrode. Ni oxidizes at high anodic potentials. Inside the potential range without electrochemical activity, the capacitance and the solution resistance, which were evaluated by impedance electrochemical spectroscopy, were compared for the two solutions tested. Conductivity measurements of the electrolytes with different compositions were also acquired. The results of cyclic voltammetry indicated that the Ni has a wide electrochemical window and low current peak densities of oxidation in the γ-butyrolactone medium than in ethylene glycol medium. The γ-butyrolactone and 1-n-butyl-3-methylimidazolium tetrafluoroborate ionic liquid solutions had the highest conductivity values. Decreased 1-n-butyl-3-methylimidazolium tetrafluoroborate ionic liquid content in different solvent mixtures resulted in an increase in the capacitance value at the Ni/electrolyte interface. The highest capacitance values were obtained for Ni in ethylene glycol and 1-n-butyl-3-methylimidazolium tetrafluoroborate medium.     

铂催化剂在有机电解液中对氨氧化的电催化性能

研究了用碳酸丙烯酯(PC)和低粘度的乙二醇二甲醚(DME)作电流型电化学氨气传感器的有机混合电解液时,氨在碳载Pt(Pt/C)催化剂电极上的电氧化性能.实验表明,Pt/C催化剂电极对氨的氧化有很好的电催化活性,稳定性、选择性和响应时间等参数均良好,而且还能耐高温低湿的条件,可解决水溶液电解液因蒸发而失效的问题,延长了传...     

Preparation,Characterization, and Electrocatalytic Properties of Cobalt Oxide and Cobalt Hexacyanoferrate Hybrid Films

Polynuclear mixed‐valent films of cobalt oxide and cobalt hexacyanoferrate (CoOCoHCF) have been deposited on electrode surfaces from a solution of Co²⁺ and Fe(CN)₆^3? ions by repetitive potential cycling method. Simultaneous cyclic voltammetry and electrochemical quartz crystal microbalance measurements demonstrate the steady growth of modified film. The effect of type of monovalent cations as well as acidity of the supporting electrolyte on film growth and redox behavior of resulting film was investigated. In pure supporting electrolyte, electrochemical responses of modified electrode resemble with that of a surface immobilized redox couple. The hybrid film electrodes showed electrocatalytic activity toward oxidation of NADH, hydrazine and hydroxylamine. The feasibility of using our modified electrodes for analytical application was also explored.     

Adsorption characteristics of electrodes containing nanostructured carbon of different morphology

The effect of camphor adsorption on the differential capacitance of electrodes of nanostructured carbon of different morphology (single-walled carbon nanotubes, filiform carbon, and columnar structures) in aqueous electrolyte solutions and also on the electrochemical reactions in these systems is studied. It is shown that irrespective of the ac frequency, the differential capacitance of the nanopaper and columnar electrodes increases 3–5-fold throughout the studied potential range. This experimental fact is explained by the substantial increase in the electrode surface accessible for electrolyte, which is a manifestation of the Rehbinder effect in electrochemistry. The revealed different kinds of effects of camphor adsorption layers formed at the nanostructured carbon/electrolyte interface on the electron transfer processes are as follows: partial inhibition of both the electron injection and the K₃[Fe(CN)₆] reduction; complete suppression of the reduction of sodium nitrate and nitrite; the absence of effects on the OH radical reduction and solvated electron oxidation.     

Electrooxidation mechanisms and discharge characteristics of borohydride on different catalytic metal surfaces

The electrooxidation behavior of BH4(-) on electrocatalytic Pt, hydrolytically active Ni, and noncatalytic Au electrodes were comparatively reexamined and a more generalized reaction mechanism was proposed to explain the very different anodic properties of BH4(-) on the different metal electrodes. In this mechanism, the anodic reaction behavior of BH4(-) are determined by a pair of conjugated reactions: electrochemical oxidation and chemical hydrolysis of BH4(-), the relative rates of which depend on the anodic materials, applied potentials, and chemical states of the anodic surfaces. At Pt surface, the electron number of BH4(-) oxidation increases with the increased potential polarization, while the actual electron number of BH4(-) oxidation on Ni electrode is 4 at most due to the poor electrocatalytic activity of the oxidized Ni surface and the strong catalytic activity of metallic Ni for chemical recombination of the adsorbed H intermediate. On the hydrolytic-inactive Au surface, the anodic reaction of BH4(-) can proceed predominately through direct electrochemical oxidation, delivering a near 8e discharge capacity.     

Impedance Study of GaN and InGaN Semiconductor Anion Selective Electrodes

The response of potentiometric anion selective electrodes employing undoped GaN or In_0.2Ga_0.8N films as sensing element to detect various anions was investigated in solutions of KF, KNO₃, KCl, HOC₆H₄COONa, KSCN, CH₃COOK, KClO₄ and KBr salts. The calibration plots for the GaN and In_0.2Ga_0.8N semiconductor electrodes contained linear regions extending over four decades of activity change in most solutions. The structure of the GaN and In_0.2Ga_0.8N semiconductor electrode/ electrolyte interface was studied through electrochemical impedance spectroscopy. Analogous equivalent circuits modeling the GaN or In_0.2Ga_0.8N electrode/electrolyte interface were proposed and their parameters were calculated. The space charge layer of the GaN and In_0.2Ga_0.8N semiconductors dominated the impedance of the electrochemical system at high frequencies (>10 kHz), whereas at low frequencies (<10 kHz), the impedance was controlled by the diffusion of electroactive species across the layer of adsorbed ions at the surface of the electrode. Results imply a strong dependence of the electrodes performance on the adsorption capacity of tested anions.     

二甲醚的电催化氧化反应

 考察了负载于镓酸镧基电解质上的镍电极与镍－钐掺杂氧化铈复合电极电催化二甲醚氧化反应的特性．结果表明，反应的主要产物均为CO，H2和CH4，同时生成少量完全氧化的产物H2O和CO2．在开路电位下二甲醚发生裂解反应，生成的CO，H2和CH4三种主要产物的比例接近于1．在有电泵氧存在下，二甲醚的电催化氧化反应强烈地依赖于阳极及电解质材料的组成．Ni／La0．9Sr0．1Ga0．8Mg0．2O3界面上发生的主反应是二甲醚的部分氧化，且存在有严重的积碳现象．电极中掺入SDC（15％Sm3＋－掺杂的CeO2）后，二甲醚完全氧化性能明显增强；随着电流的增大，氢的生成速率显著减小，并生成大量的H2O．采用掺钴镓酸镧基电解质后，Ni－SDC主要表现为催化二甲醚部分氧化反应，且显著抑制了积碳的发生．Ni－SDC／La0．8Sr0．2Ga0．8－Mg0．11Co0．09O3上二甲醚电催化氧化反应的主要产物为1∶1的CO和H2．掺钴电解质引起Ni－SDC具有特殊的催化性能，可能与电解质中p型电导的存在有关．