非晶态Ni-S-Mn三元合金电极析氢行为

非晶态Ni-S-Mn三元合金电极析氢行为;电极;析氢电催化活性;水电解;非晶态合金     

球磨形成的Ni-Mo纳米晶复合镀层上的析氢反应

采用复合电镀的方法将不同球磨时间制备的高催化活性的纳米晶，Ｎｉ－Ｍｏ合金粉直接镀于电极表面，并用稳态极化曲线及交流阻抗技术测试了这些电极析氢的电化学活性，同时用Ｘ射线衍射，透射电镜及扫描电镜监测了Ｎｉ－Ｍｏ合金粉的物相结构，晶粒尺寸及复合电极表面的形貌，并初步探讨了这些复合电极的析氢机理，实验结果表明，球磨不仅可使镍钼粉合金化成为纳米晶，同时随着球磨时间的增加，纳米晶晶粒继续细化，电极的析氢催化活     

纳米氧化铜掺杂对储氢合金电极性能的影响

采用纳米氧化铜作为添加剂制备储氢合金电极, 考察了氧化铜对储氢合金电池储备容量的调节作用, 分析了掺杂后电极及电池质量的变化, 研究了掺杂合金电极的电化学性能, 并用SEM、EIS、CV等方法分析了反应的电化学机理. CV、SEM结果表明, 氧化铜在首次充电过程中被还原成低价态沉积在合金颗粒表面, 由于氧化铜比容量远大于合金, 可以通过掺杂氧化铜调节合金的储备容量. 电化学测试结果表明, 掺杂合金电极具有更好的高倍率充放电能力和循环性能. EIS分析结果表明, 掺杂合金电极导电性增强, 电化学活性提高.     

巯基化改性壳聚糖在电化学生物传感器制备中的应用

以壳聚糖、N-乙酰-L-半胱氨酸(NAC)为原料,以1-羟基苯并三唑(HOBt)和1-乙基-3-(3-二甲基胺丙基)碳化二亚胺盐酸盐(EDAC)为缩合剂,合成功能化壳聚糖衍生物巯基壳聚糖(CHS-NAC).用红外光谱(FTIR)、核磁共振(1H-NMR)及X射线衍射(XRD)对其结构进行表征,用Ellman’s试剂通过标准曲线法测得巯基含量.利用CHS-NAC的黏附性,通过层层吸附的方法将CHS-NAC、纳米金及细胞色素c分别修饰到玻碳电极(GC)上,通过扫描电子显微镜(SEM)对修饰电极表面的形貌进行了观察,采用循环伏安和电化学阻抗研究了不同修饰膜电极的电化学行为,及扫描速率对细胞色素c修饰电极的影响,并开展了对过氧化氢的电催化分析.实验结果表明,CHS-NAC能高效地将纳米金及细胞色素c固定在电极表面,并能有效发挥纳米金辅助转移电子及细胞色素c对过氧化氢催化的能力.     

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.     

电极/反相微乳液体系电沉积制备纳米金镀层

将含有氯化金的强酸性水溶液作为水相与Triton X-100、正己醇、正己烷组成反相微乳液体系, 并以该微乳液构成电极/反相微乳液电极系统, 利用电沉积方法成功地制备出纳米Au镀层. 循环伏安和交流阻抗对反相微乳液体系电沉积过程的研究发现, 微乳液中Au(III)的还原为完全不可逆过程, 其电化学反应的阻抗值约为具有相同表观浓度氯化金水溶液体系的5.5倍. SEM研究结果表明, 利用微乳液体系电沉积获得的金镀层由纳米Au颗粒组成, 直径为50 nm左右. 所制备的纳米Au修饰电极由于具有较大的比表面积, 其电化学性能优于纯Au电极, 该电极在酸性条件下有较好的析氢性能, 在碱性条件对丙三醇有较好的电催化氧化性能.     

离子束修饰对电极表面结构和析氢活性的影响

采用了离子束对工业钛电极进行表面改性，用电化学方法研究了改性电极在Ｈ２ＳＯ４溶液中的析氢活性，用表面能谱分析了电极表面的组分和结构。结果表明：通过离子束修饰在电极表面引入微量的活性元素即可明显改善工业纯钛电极的析氢催化活性；离子束修饰改变了电极表面的组分和相结构，从而达到了改性的目的。     

铂基Pb-Sb表面合金电催化剂的制备与结构表征

通过电化学方法,在玻碳载体表面制备以Pt、Pb、Sb为主要成分的铂基Pb Sb表面合金电催化剂.运用电化学循环伏安、石英晶体微天平（EQCM）和扫描隧道显微镜（STM）技术对催化剂电极进行表征.结果表明：酸性溶液中在所制备的表面合金电极上,析氢起始电位负移至－0.45 V,表面合金的起始氧化电位为0.15 V,其稳定性明显高于电催化还原中常用的铅、锑等金属电极.通过EQCM研究表面合金电极的形成过程,结合STM观察和XPS深度剖析,确定电催化剂表面是由粒度均匀的纳米颗粒构成的表面合金层.     

Ni-P-C复合材料的制备及其电催化产氢性能研究

通过化学镀技术制备了亚微米级的Ni-P镀层石墨粉复合粉体新材料(即Ni-PC).采用扫描电子显微镜、X-射线能谱仪、X-射线粉末衍射仪对Ni-P-C复合粉体分别进行表面形貌分析、表面成分分析和物相分析.通过对Ni-P-C材料电极进行电解水析氢、循环伏安和Tafel极化等电化学测试,研究对比了Ni-P-C(石墨)材料与试剂石墨粉体以及纯Ni电极的电化学催化产氢性能.结果表明:利用化学镀技术成功地在石墨粉体表面镀上了一层亚微米级且均匀、致密的非晶态Ni-P合金.Ni-P-C(石墨)复合电极材料析氢能力强,具有良好的电化学活性.     

IrO2电极在含有机小分子水溶液中的电化学活性

通过循环伏安（CV）与电化学阻抗谱（EIS）测试研究了Ti基IrO2系活性涂层电极在含甲醇、甲酸及甲醛三种有机小分子的Na2SO4溶液中的电化学活性,其中以电极/溶液界面的双电层电容来表征电极的活性.结果表明,与同浓度H2SO4溶液相比,该电极在Na2SO4溶液中的电化学活性发生明显下降.有机小分子的加入降低了电极的活性表面积.发现有机物能在较宽的电位范围内发生氧化反应,但在该种电极上的电氧化速率较慢.然而,伴随着析氧反应的发生,有机物的氧化也随之加快.     

在纳米晶Co－Mo／Ni复合电极上的析氢反应

采用复合电镀的方法将不同球磨时间制备的高催化活性的纳米晶Ｃｏ－Ｍｏ合金粉直接镀在电极表面,用稳态极化曲线及交流阻抗技术测试了这些电极析氢的电化学活性,并用Ｘ射线衍射、透射电镜及Ｘ射线光电子能谱、扫描电镜监测了Ｃｏ－ＭＯ合金粉的物相结构、晶粒尺寸和复合镀层的成份、形貌,实验结果表明,Ｃｏ－Ｍｏ纳米晶合金粉有较高的析氢催化活性。球磨使钴钼粉合金化成为纳米晶,一方面增加了复合镀层的真实表面积,另一方面由于纳米晶合金具有高比例的表面活性原子,致使析氢活化能降低,加快了析氢反应,研究表明在不太高温度下,电化学脱附的活化能和整个析氢反应的活化能一致。说明电化学脱附为速度控制步骤。     

Hydrogen evolution on Pt and polyaniline modified Pt electrodes—a comparative electrochemical impedance spectroscopy study

Kinetic of hydrogen evolution reaction, HER, at Pt and polyaniline, PANI, polymer film modified Pt electrodes in the sulphuric acid solution was investigated within the context of possible inhibition of HER by conducting polymers. Pt/PANI electrodes were prepared by electro-polymerization procedure with different quantities of PANI and electrochemically aged in the insulating state prior polarization and electrochemical impedance spectroscopy experiments. Polarization and impedance data obtained in the hydrogen (0.30 to 0.05 V_RHE) and HER (0.00 to ?0.155 V_RHE) potential regions of bare Pt-poly electrode were compared with those of Pt/PANI electrodes. Significant differences of impedance spectra in the hydrogen region of potentials pointed toward domination of hydrogen under-potential deposition, H UPD, at Pt-poly surface and domination of PANI impedance at Pt/PANI electrodes, respectively. Quite similar impedance spectra obtained in the HER region of potentials and Tafel slopes of about 30 mV decade^?1 evaluated from polarization measurements indicated that HER is proceeding by the same mechanism at Pt-poly and Pt/PANI electrodes, respectively. Analysis of respective impedance parameters showed that HER which is easily driven at Pt-poly electrode becomes inhibited to a certain extent at both Pt/PANI electrodes, but more for the one with higher quantity of PANI. These results can commonly be interpreted by HER that is taking place on the Pt substrate underlying more or less porous PANI film acting as a barrier toward electrolyte solution.     

贮氢合金表面处理改善Ni/MH电池1C充放电性能

研究了贮氨合金两种表面化学处理方法对MH电极活化性能及Ni／MH电池IC充放电性能的影响：第一种处理方法是贮氢合金在6th。l·L－’KOH溶液中80T处理sh，第二种处理方法是在含有0．04mol·L－‘KBH4的6mol·L’‘KOH溶液中80t处理sh．通过MH电极的放电容量、充放电过程中电极极化和电化学阻抗谱测试评价了上述化学处理对电极活化性能的影响．电子探针表面分析表明化学处理后贮氢合金表面由于铝元素的优先溶解形成一层具有较高电催化活性的富镍表面层，它是改善电极活化性能的主要原因·以处理的贮氨合金为负极材料的Ni／MH电池具有较高IC充放电循环寿命和1．ZV以上放电容量．     

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.     

苯甲酸在疏水性复合电极上的电化学还原行为

以铜片和锌片为基材,复合电镀制得Cu-PTFE(聚四氟乙烯)和Zn-PTFE疏水性复合电极,并将复合电极应用于苯甲酸的电化学还原行为研究。测定了复合电极在电解液中的Tafel极化曲线、循环伏安、电极稳定性和交流阻抗等电化学参数。结果表明,在苯甲酸电还原制备苯甲醛中,Cu-PTFE复合电极相对于Zn-PTFE复合电极具有较高的催化活性,其电还原产率分别为88.4%和79.2%,因此,Cu-PTFE复合电极有望成为苯甲酸电化学还原制备苯甲醛的电极材料。电化学行为的研究结果显示,苯甲酸在疏水性复合电极上的电还原过程可能只受电子迁移过程控制。     

动态阻（容）抗法研究Cl－对银铟硒上电化学振荡的影响

采用现场动态阻（容）抗法测试技术,研究在不同支持电解质溶液中,过氧化氢在电沉积银铟硒电极上阴极还原过程的电化学振荡行为,振荡前后,电极的表面组成亦由ＡＥＳ能谱测得。根据实验结果,详细讨论了氯离子对此电化学振荡机理的影响。     

Electrocatalytic evolution of hydrogen on porous alumina/gelcast-derived nano-carbon network composite electrode

We presented a way to fabricate new porous alumina/gelcast-derived nano-carbon network (NCN) composite electrode using gelcasting and reduction-sintering method. The morphology, crystalline phases, and nanostructure of the alumina/NCN electrode were characterized. The electrocatalytic activity of this elelctrode toward hydrogen evolution reaction (HER) in alkaline solutions was investigated. The electrocatalytic activity analyzed by cyclic voltammetry exhibited the onset potential for HER shifted in the positive direction favoring hydrogen generation with lower overpotential on the porous electrode, compared with pure carbon electrode. This behavior was attributed to the high porosity and electrochemical surface area as well as the nanostructure of the electrode that was pyrolyzed nano-carbon networks introduced into the alumina ceramic matrix, which can greatly enhance the electrode electrocatalytic activity toward HER. The associated kinetic parameters of HER were systematically investigated using electrochemical impedance spectroscopy.     

Electrochemical Properties of Carbon Black AD-100 and AD-100 Promoted with Pyropolymer of Cobalt Tetra(p-methoxyphenyl)porphyrin

Carbon black AD-100: initial, activated, and promoted with pyropolymer of cobalt tetra(p-methoxyphenyl)porphyrin is characterized by a complex of electrochemical (floating electrode, rotating disk electrode, rotating ring-disk electrode, electrochemical impedance) and structural (standard porosimetry, BET) methods of investigation. Procedures for the AD-100 activation and promotion and the preparation of thin layers of the material to be studied and deposited on disk electrodes are described. The effect of the activation and promotion of carbon black on the surface and electrocatalytic activity of materials under study in the reduction of oxygen and hydrogen peroxide is shown. The ratio of constants of oxygen reduction directly to water and through intermediate formation of hydrogen peroxide is determined. A path for the oxygen reduction is discussed.     

Three steps in the anode reaction of the polymer electrolyte membrane fuel cell. Effect of CO

We studied the influence of CO poisoning of the anode in the polymer electrolyte membrane fuel cell (PEMFC) using electrochemical impedance spectroscopy (EIS). The anode impedance was found by first feeding neat hydrogen gas and next hydrogen with CO into one of the electrodes, keeping neat hydrogen gas on the other electrode as a reference. The electrodes were E-TEK Elat gas-diffusion electrodes with 0.5 mg Pt/cm², and the membrane was Nafion^® 117. The CO concentration was 103 ppm, and the total pressures were 1, 2.5 and 4 bar. Operating temperatures were kept constant, 30.0 °C or 50.0 ± 0.1 °C. Bias voltages of 0 and 0.05 V were used. Three steps were revealed in the reaction mechanism, the slow adsorption/diffusion step, the charge transfer step and the proton hydration step, confirming earlier results. Carbon monoxide affects the charge transfer step by blocking active sites and by affecting the surface polarisation. We further conclude that CO adsorbs to the porous carbon matrix, and reduces significantly the rate of surface diffusion of hydrogen to the surface.     

纳米多孔Ni、Ni3S2/Ni复合电极的制备及其电催化析氢性能

采用脱合金化和水热合成的方法制备纳米多孔Ni和纳米多孔Ni₃S₂/Ni复合电极。通过N₂吸附-脱附测试、XRD、SEM、TEM等方法表征电极的孔径分布、物相和微观结构。在1 mol·L^-1的NaOH溶液中,运用线性扫描伏安（LSV）曲线、交流阻抗（EIS）谱图、恒电流电解法等测试电极的电催化析氢性能。结果表明：在电流密度为50 mA·cm^-2时,与纳米多孔Ni相比,Ni₃S₂/Ni合金具有更低的析氢过电位以及更高的析氢活性,同时纳米多孔Ni₃S₂/Ni复合电极具有更低表观活化能和电子转移阻抗,进一步明确了过渡金属硫化物对电催化析氢性能的特殊贡献。