现场光谱电化学研究的新进展

电化学以两个凝聚相的荷电界面为其主要研究对象．它广泛地应用于能源、材料等重要科学领域，并对生命科学的发展发挥着重要作用［1，2］．为了从分子水平上深化对电化学界面的认识，自七十年代中至八十年代初采用了紫外可见反射、拉曼和红外光谱技术对电化学体系进行现场（in-situ，又称原位）研究，开创了光谱电化学新领域[3,4]．光谱电化学在／＼十年代发展迅速，推动电化学研究由宏观进入微观、由统计平均深入至分子水平【‘一刀．近年来，随着各种光谱仪器性能的提高以及非线性光谱等新技术的发展，现场光谱电化学研究不断拓宽新领域，…     

核黄素的薄层荧光光谱电化学研究

光谱检测技术和电化学手段密切结合起来的光谱电化学方法,加上薄层池的整体快速电解,已成为化学工作者的重要研究手段［１］．目前紫外可见透射光谱检测方法多采用铂、金、石墨等的网栅为工作电极,对其透光度及强度均有一定要求,操作不便,池也不易清洗［２］;并且由...     

4-[2-(4-N,N-二甲基苯胺基)乙烯基]吡啶氧化物的电化学行为

半菁染料是人们制造ＬＢ膜的材料之一．近年来,为得到电导率较高的薄膜,电荷转移络合物的ＬＢ膜受到重视［１］．实验证明,有机材料的ＬＢ膜经化学修饰或改性以后,电导率大大增加．化学工作者常将有机染料分子用来修饰电极,在光电化学、电催化等方面有较好的效果,因而,受到人们极大的关注．化学工作者已成功地制备出许多染料化学修饰电极,研究膜修饰电极的电化学行为［２,３］,而用循环伏安法和光谱技术对有机染料的电化学行为研究得较少［４,５］．本文对４ ［２ (４ Ｎ,Ｎ 二甲基苯胺基 )乙烯基］吡啶氧化物这个新改性的半菁化…     

四(α-萘基)四苯并卟啉钴配合物的光谱电化学性质

Ｋｅｌｅｔ等［１］研究ＣｏＴＭＡＰＩ催化水制取氢气的反应时指出，活性中心是一价钴卟啉．曹锡章等［２］研究钴卟啉催化ＣＯ２电化学还原时指出，活性中心也是一价钴卟啉．然而，不稳定价态的金属卟啉配合物的制备和性质研究较为困难．光谱电化学的迅速发展为不稳定价...     

F-的轴向配位对(TPP)Co电化学氧化还原的影响研究

钻卟啉的电化学氧化还原行为受轴向配位作用的影响很大［1－5］。通过循环伏安跟踪的阴离子滴定可以细致地考察此影响过程,但至今很少见文献报道［4,5］．我们曾研究了Br-和Cl-存在时,（TPP）Co的电化学氧化行为特征,结果显示不同的卤离子对（TPP）Co电化学氧化还原过程的影响程度有相当大的差别［6,7］．本文以循环伏安跟踪的F-滴定和光谱电化学方法研究了F-的轴向配位效应对（TPP）Co在1,2一二氯乙烷中电化学氧化还原过程的影响．1试剂与仪器1,2一二氯乙烷（DCE,北京化工厂,分析纯）,在CaH。上分馏纯化后使用,四丁基高…     

原位光谱电化学技术对有机染料分子电极过程的研究

原位光谱电化学技术对有机染料分子电极过程的研究①唐寅轩杨杭生沈报恩＊（杭州大学化学系杭州３１００２８）有机染料分子修饰电极在光电化学，电催化等方面的应用均有较好的效果，因而受到人们极大的注意．近年来已经制备成功许多染料化学修饰电极［１］．原位光谱电化...     

椭圆偏振光谱方法对电化学的研究及应用

椭圆偏振光在固体表面入射和反射后,光学参量△,Ψ及其所表征的偏振状态,将因固体表面膜的厚度、性质不同而发生相应的变化．测定△,Ψ及其变化规律、可为固体材料、表面膜厚度、表面或界面上发生的有关物理或化学变化等直接或间接地提供信息,其灵敏度可反映表面膜层０．１～０．０１ｎｍ厚度的变化．因此,椭圆偏振光谱（下称椭圆法）在固体物理、表面化学、金属表面腐蚀、生物大分子表面等研究领域具有重要价值［１］．该法能检测的表面膜厚相当于电极上的单分子层的尺寸,特别适用于从分子水平上研究电化学体系,是最灵敏的光谱电化…     

电化学谱学表征方法的应用与发展

经历两个多世纪的发展,电化学表征方法的理论和实验研究不断完善,在表界面精细结构表征、电化学反应机理研究等方面起到重要作用。电化学谱学表征技术的出现,填补了传统电化学表征方法在分子水平上鉴定电化学反应活性位点及中间物种的空白。本文总结了近年来红外光谱(IR)、表面增强拉曼光谱(SERS)及和频振动光谱(SFG)三种经典分子振动光谱电化学表征技术的研究进展。首先介绍了三种光谱的基本原理和电化学联用电解池的设计,然后从基础电化学理论出发,介绍其在模型单晶体系及界面水机理研究中的应用,进一步重点介绍了其在锂离子电池和燃料电池领域的相关研究进展,最后展望了电化学谱学表征技术的未来发展方向。     

辅酶Ⅰ电化学配位反应机理的紫外光谱电化学研究

用薄层池原位紫外光谱电化学法研究了辅酶Ⅰ(NAD)在银电极上的电化学配位反应机理。实验结果表明：NAD能与溶出的银离子生成配合物，该配合物的配位反应是一种可逆过程，用光谱电化学的Nernst图解分析获得银离子与NAD配合物的主要存在形式是［Ag(NAD)₂］⁺，银离子是与NAD分子的腺嘌呤基团形成配合物的。配合物的银离子与银电极表面发生异相电子交换反应，该电化学反应是受吸附控制的准可逆电极过程。     

红外光谱电化学

光谱电化学是目前电化学中最活跃的研究领域之一。它具有电化学技术易于控制表面性质、反应能量的优点,又具有光谱易于从微观角度观察电极-溶液界面上有关结构和键合的性质。当前应用的原位法(定位法,In Situ)是在保持研究体系原有环境的基础上从分子级     

血红蛋白在裸银电极上的直接电化学及其分析应用

报道了血红蛋白(Hb)在裸银电极上的电化学氧化还原行为。在+0.4～-0.2V(vs.SCE)电位范围内于pH=4.5的0.1mol/LNaAc-HAc底液中,血红蛋白产生一对灵敏的氧化还原峰。峰电位之差△E为0.25V(扫描速度20mV/s).动力学研究表明:电极反应的电子转移数n为0.94,表现电子传递速率常数Ks为0.032.连续电位扫描30min,峰电流变化分别为0.2μA(还原峰)和0.15μA(氧化峰).两峰与血红蛋白浓度在2×10^-7～2×10^-6mol/L和2×10^-6～1.5×10^-5mol/L范围内均呈良好线性关系,已应用于血红蛋白的分析测定。     

Thermodynamics of silver—silver halide electrodes and thermodynamic solubility products of silver halides in glycerol + water mixtures at different temperatures

The standard potentials of silver—silver bromide and silver—silver iodide electrodes in glycerol+water mixtures containing 5, 10, 20 and 30 wt% glycerol were determined from electromotive force measurements of the cell Ag(s), AgX(s), KX(c)//KCl(c), AgCl(s), Ag(s), where X is Br or I, at seven different temperatures in the range 5–35°C. The standard potentials in each solvent are represented as a function of temperature. The standard thermodynamic functions for the electrode reactions, the primary medium effects of various solvents upon X⁻, and the standard thermodynamic quantities for the transfer of 1 g-ion of X⁻ from water to the respective glycerol + water media are evaluated and discussed in the light of ion—solvent interactions as well as the structural changes of the solvents. From the values of the Ag/Ag⁺ and Ag/AgX, X⁻ electrodes, the thermodynamic solubility product constants of silver chloride, silver bromide and silver iodide have been determined in glycerol + water solvent mixtures at different temperatures.     

Electrochemical behavior of methyl viologen at graphite electrodes modified with Nafion sol–gel composite

Electrodes were prepared by spin-coating spectroscopic graphite rods with a Nafion doped sol. Coating solutions consisting of Nafion:TEOS (tetraethoxysilane) ratios of 3:1 and 4:1 gave smooth films on the electrode surface. These modified electrodes were evaluated and compared with Nafion modified and bare spectroscopic graphite electrodes using methyl viologen (MV²⁺) as a representative cationic electroactive probe. Substantial partitioning of MV²⁺ into the Nafion:sol–gel matrix to the electrode surface was observed by cyclic voltammetry and square wave voltammetry. Cyclic voltammograms of MV²⁺ in 0.1 M NaCl at Nafion:sol–gel 4:1 modified electrodes showed a reversible reduction to MV⁺ with E^0′=−0.695 V vs. Ag/AgCl. Results of scan rate variation showed the wave to be characterized by semi-infinite diffusion for scan rates in the range 50–500 mV/s. Slowing the scan rate below 50 mV/s resulted in a transition to thin-layer behavior. MV²⁺ partitioned much more quickly into the sol–gel-Nafion modified electrodes compared to pure Nafion modified electrodes. Reversibility of the MV²⁺-loaded modified Nafion-doped sol–gel coatings on electrodes was obtained by soaking in 1 M NaCl solution. Concentration calibration plots for MV²⁺ at the sol–gel-Nafion modified electrodes were nonlinear. Substantial enhancement of current signal at low concentrations was observed by square wave voltammetry.     

New aspects of the reaction of silver(I) cations with the ethylenediaminetetraacetate ion

The highly neutralized ethylenediaminetetraacetate (EDTA) titrant (95–99% as Y⁴⁻ anion) precipitates with Ag⁺ cations to form the Ag₄Y species, in aqueous medium, which is well characterized from conductometric titration, thermal analysis and potentiometric titration of the silver content of the solid. The precipitate dissolves in excess Y⁴⁻ to form a complex, AgY³⁻. Equilibrium studies at 25°C and ionic strength 0.50 M (NaNO₃) have shown from solubility and potentiometric measurements that the formation constant (95% confidence level) β₁ = (1.93 ± 0.07) × 10⁵ M⁻¹ and the solubility products are K_S0 = [Ag +]⁴[Y⁴⁻] = (9.0 ± 0.4) × 10⁻¹⁸ M⁵ and K_S1 = [Ag +]³[AgY³⁻] = (1.74 ± 0.08) × 10⁻¹² M⁴. The presence of Na⁺, rather than ionic strength, markedly affects the equilibrium; the data at ionic strength 0.10 M are: β₁ = (1.19 ± 0.03) × 10⁶ M⁻¹, K_S0 = (1.6 ± 0.4) × 10⁻¹⁹ M⁵ and K_S1 = (1.9 ± 0.5) × 10⁻¹³ M⁴; at ionic strength tending to zero; β₁ = (1.82 ± 0.05) × 10⁷ M⁻¹, K_S0 = (2.6 ± 0.8) × 10⁻²² M⁵ and K_S1 = (5 ± 1) × 10⁻¹⁵ M⁴. The intrinsic solubility is 2.03 mM silver (I) in 0.50 M NaNO₃. Well-defined potentiometric titration curves can be taken in the range 1–2 mM with the Ag indicator electrode. Thermal analysis revealed from differential scanning calorimetry a sharp exothermic peak at 142°C; thermal gravimetry/differential thermal gravimetry has shown mass loss due to silver formation and a brown residue, a water-soluble polymeric acid (decomposition range 135–157°C), tending to pure silver at 600°C, consistent with the original Ag₄Y salt.     

Cation selectivity of ionophores based on tripodal thiazole derivatives on benzene scaffold

The synthesis and potentiometric evaluation of new 1,3,5-tris(thiazolylcarbethoxy)-2,4,6-trimethylbenzene (3), 1,3,5-tris(thiazolylhydroxy)-2,4,6-trimethylbenzene (4), 1,3,5-tris(thiazolylmethyl)-2,4,6-trimethylbenzene (5), and 1,3,5-tris(thiazolylphenyl)-2,4,6-trimethylbenzene (6), toward mono and divalent cations under various pH conditions are outlined. The ion-selective properties of the newly synthesized compounds were studied by measuring the potentiometric responses of the 3-, 4-, 5-, and 6-based membrane electrodes to alkali metal, alkaline earth metal, ammonium, and transition metal ions, under various pH conditions. The 3-based electrode exhibited a Nernstian response to ammonium and potassium under alkaline pH conditions, while the other three electrodes showed a poor potentiometric performance. All electrodes showed substantial responses to silver ion under acidic condition, but there was almost nil response to other transition metal ions (Fe²⁺, Co²⁺, Zn²⁺, Ni²⁺, Pb²⁺, Cd²⁺, Cu²⁺ and Hg²⁺). The 3- and 5-based electrodes resulted in near Nernstian responses (51.3 mV and 59.5 mV/pAg⁺, respectively) with low detection limits (100 ppt), while the 4- and 6-based ones showed sub-Nernstian below 40 mV/pAg⁺. The results were interpreted with semi-empirically modeled structures.     

阿拉伯糖基有序介孔碳修饰电极检测盐酸奈福泮的研究

以阿拉伯糖为碳源,介孔硅(SBA-15)为模板剂,用硬模板法制备有序介孔碳材料,采用场发射扫描电镜(Scanning Electron Microscopy,SEM)、透射电子显微镜(Transmission Electron Microscope,TEM)、全自动比表面及孔隙度分析仪(Brunner Emmet Teller,BET)、X射线衍射(X-ray Diffraction,XRD)、X射线光电子能谱(X-Ray photoelectron spectroscopy,XPS)对材料进行表征。用滴涂法将有序介孔碳悬浊液滴在裸玻碳电极表面,得到有序介孔碳修饰电极。用循环伏安法来研究盐酸奈福泮在有序介孔碳修饰的玻碳电极(Glassy Carbon Electrode,GCE)上的电化学行为。在最佳条件下,盐酸奈福泮浓度在1.0×10^-8~1.0×10^-5mol·L^-1范围内与峰电流呈线性关系,相关系数为R²=0.9932,检出限为3.2×10^-9 mol·L^-1。对盐酸奈福片中盐酸奈福泮进行了检测,样品加标回收率为96.84%~102.50%,RSD<5.0%。     

三维纳米枝状物表面制备蛋白质印迹聚合物及其性能

在金电极表面制备了3D金/铜纳米枝状物,并以丙烯酰胺为功能单体,N,N-亚甲基双丙烯酰胺为交联剂,血红蛋白为模板分子,在枝状物表面成功制备了蛋白质印迹聚合物。利用循环伏安法和扫描电子显微镜对制备的聚合物修饰电极进行了表征,通过微分脉冲伏安法、利用制备的聚合物修饰电极可对溶液中的血红蛋白进行检测,得到比已报道的类似印迹传感器更宽的检测范围和更低的检测下限,其线性范围为1.0×10~(-14)~1.0×10~(-1)mg/L,检测限为1.9×10~(-15)mg/L(S/N=3),相关系数为0.9975。实验结果表明,在电极表面制备的金/铜纳米枝状物,大大提高了电极的电子传递能力,也提高了印迹聚合物修饰电极的检测范围。     

以椰壳生物质炭为燃料的直接炭固体氧化物燃料电池

通过热裂解制得椰壳炭,表征了其结构和组成,并将其用于电解质为钇稳定化氧化锆（YSZ）、电极材料为银和钆掺杂氧化铈（Ag-GDC）的固体氧化物燃料电池（SOFC）的燃料,对所构成的直接炭固体氧化物燃料电池（DC-SOFC）的性能进行了测试研究。结果表明,所制得的椰壳炭颗粒粒径在微米级别,具有介孔结构,而且椰壳炭中含有K、Ca等元素,可用作Boudouard反应催化剂。当使用椰壳炭作为DC-SOFC燃料时,在800 ℃下电池最大功率密度为255 mW/cm²;负载Fe催化剂后,最大功率密度提升为274 mW/cm²。以0.5 A/cm²的恒电流放电,0.5 g负载Fe椰壳炭燃料电池能够连续工作17.6 h,燃料利用率为39%,表明椰壳炭作为DC-SOFC燃料具有优异的性能和潜力。     

激光解吸电离飞行时间质谱下的银簇行为

近年来,对金属簇的研究已成为化学与物理学中最活跃的研究领域之一［１］．金属簇被认为是介于单个原子与固体之间的中间相［２］．深入地研究其结构、形成机理及物理与化学行为,对于寻找新的催化剂［３］,重新认识气相化学与凝聚相化学的关系［４］,都有非常重要的意...     

Photosensitization of nanocrystalline TiO2 electrodes with II B group metal-ion-bridged self-assembled films of 3,4,9,10-perylenetetracarboxylic acid

Self-assembled films (SA films) of 3,4,9,10-perylenetetracarboxylic acid (PTA) (Film P) and II B group metal-ion-bridged PTA (Film PMP, M=Zn²⁺, Cd²⁺, or Hg²⁺) were fabricated on nanocrystalline TiO₂ electrodes and characterized with UV–VIS and IR spectra and XPS. Compared with Film P sensitized solar cell, Grätzel cells based on individual PMP electrodes are more efficient regarding photocurrent generation. Synchrotron radiation photoelectron spectroscopy (SRPES) study reveals that those HOMO energy levels of PMP films are greater than that of Film P. The higher HOMO energy levels will lead to higher excited state energy levels that benefit electron injection, and hence, increase efficiencies for photocurrent generation. In view of the invariable valence of Zn²⁺, Cd²⁺, and Hg²⁺ ions, electron injection should be attributed to ligand, but not to the central metal ions, like the case of Ru(II)–bipyridyl complex.