酞菁镍-表面活性剂薄膜修饰电极及其催化性能的研究

将酞菁镍(NiPc)掺入阳离子表面活性剂双十二烷基二甲基溴化铵(DDAB)的氯仿溶液中,并涂布于热解石墨电极表面,待氯仿挥发后制得NiPc-DDAB薄膜电极。循环伏安实验表明,在KBr溶液中,该薄膜电极有两对良好且稳定的还原氧化峰,第一对峰的E_pc1=-0.64V,E_pa1=-0.60V(vs.SCE);第二对峰的E_pc2=-0.84V,E_pa2=-0.80V,本文着重探讨了第二对峰的电化学行为,估计了该体系的电化学参数如电子扩散系数De和非均相电极反应速率常数k^0'.该薄膜电极可用于催化各种卤代乙酸的电化学还原,用多种表面分析技术对该薄膜进行了表征。     

四磺酸酞菁钴-DDAB表面活性剂薄膜电极的电化学与电化学催化研究

四磺酸酞菁钴配合物阴离子(CoPcTS_4-)在水溶液中可借助离子交换进入阳离子表面活性剂双十二烷基二甲基溴化铵(DDAB)薄膜,从而形成CoPcTS_4-DDAB薄膜电极.循环伏安法表明,该薄膜电极在pH7.0的空白缓冲溶液中十分稳定,有两对准可逆的还原氧化峰,其中第一对峰的E_pc1=-0.28V,E_pa1=-0.18V(vs.SCE),为中心离子Co(II)Co(I)的还原氧化峰;第二对峰的E_pc2=-1.30V,E_pa2=-1.18V,为酞菁环的还原氧化峰.应用循环伏安法估计了该薄膜体系的电荷传递扩散系数D_ct和表观非均相电极反应速率常数k^o'.CoPcTS_4-DDAB薄膜电极可用于对三氯乙酸(TCA)的电化学催化还原.催化电流与TCA浓度在4×10^-5～1×10^-3molL范围内成线性关系.     

酞菁钴－表面活性剂薄膜修饰电极及其催化性能

将酞菁钴(CoPc)掺入阳离子表面活性剂双十二烷基二甲基溴化铵(DDAB)的氯仿溶液,并涂布于热解石墨电极表面,待氯仿挥发后即制得CoPc-DDAB薄膜电极。循环伏安实验表明,在KBr溶液中,该薄膜电极有一对良好且稳定的还原氧化峰,E_pc=-0.45V,E_pa=-0.24V(vs.SCE).探讨了该体系的电化学行为,估计了该体系的电化学参数。可将该薄膜电极用于催化卤代乙酸的电化学还原。     

电化学还原预处理对BiVO_4薄膜电极光电化学氧化水性能的提高

在酸性水溶液中(pH=2.0),采用电化学还原(ER)方法对BiVO4薄膜电极进行预处理,并探讨了其对薄膜电极光电化学氧化水性能的影响.结果表明,这种预处理可显著提高电极的光电化学氧化水的性能,且具有良好的光电化学稳定性.利用扫描电子显微镜、X射线衍射、拉曼光谱、光电子能谱、紫外-可见漫反射光谱、荧光光谱、电化学阻抗谱及Mott-Schottky等方法对ER处理前后的电极进行了表征.结果表明,ER预处理使电极粗糙度增大,表面积增大约1.4倍;电极材料的晶型无明显变化,但V—O对称伸缩振动略有红移;表面Bi,V和O结合能变小,Bi3+部分被还原,Bi/V原子比增大;ER处理导致电极平带电位负移,光生载流子在薄膜电极/溶液界面转移速率加快,表面复合速率降低.这些变化和表面积增加是BiVO4电极光电化学性能提高的主要原因.     

血红蛋白在双十二烷基二甲基铵-聚乙烯硫酸盐多双层复合薄膜电极上的电化学与电催化

将Hb涂布到由双十二烷基二甲基铵－聚乙烯硫酸盐（2C12N^ PVS^-)在热解石墨（PG）电极表面形成的薄膜上，即可形成稳定的Hb-2C12N^ PVS^-薄膜。在pH5.5的缓冲溶液中，该薄膜电极在-0.18V(vs.SCE)左右有一对相当可逆的循环伏安还原氧化峰，为Hb血红素辅基Fe(Ⅲ）／Fe(Ⅱ)电对的特征峰，在-1.08V左右HbFe(Ⅱ）被进一步还原成HbFe(Ⅰ)。在2C12N^ PVS^-薄膜的微环境中，Hb与PG电极之间的电子传递得到极大促进，并显示了较好的稳定性。应用所建立的薄层电化学模型和E^0′分散模型，对pH7.0缓冲溶液中Hb-2C12N^ PVS^-薄膜电极的方波伏安图进行非线性回归拟合处理，获得该体系平均式量电位E^0′和表观异相电子传递速率常数ks。Hb-2C12N^ PVS^-薄膜可以催化还原氧和某些有机卤化污染物，如：三氯乙酸（TCA）。     

铕-二茂铁衍生物配合物修饰电极的电化学行为

研究了影响铕 二茂铁衍生物配合物薄膜修饰电极伏安性质的各种因素 ,讨论了薄膜电极的电荷传递过程。在LiClO4 和甘氨酸底液中 ,在 0～ 0 8V(vs.SCE)电位范围内可观察到修饰电极的氧化还原峰 ,薄膜修饰电极在底液中是一种薄层扩散过程 ,用计时库仑法测得其表观扩散系数为 2 1× 1 0 - 10 cm2 ·s- 1。溶液平衡离子的水合半径大小、离子强度、溶剂对薄膜的溶胀性质以及薄膜的厚度是影响薄膜修饰电极伏安性质的主要因素。同时测定了电极反应的表观速率常数ks 为 6 7× 1 0 - 1s- 1。     

SOD-PVP/Au电极的电化学行为及对H_2O_2的电催化

以聚乙烯吡咯烷酮K30为电催化剂,羧甲基纤维素为膜固定剂,将超氧化物歧化酶固定在电极上,制备了SOD-PVP/Au修饰电极.采用循环伏安法研究了该修饰电极的电化学行为,在pH7.0 PBS缓冲溶液中于0.305V和0.111V处出现一对明显的氧化还原峰,电极反应是一个受扩散控制的准可逆过程,扩散系数4.71×10~(-7)cm~2/s、异相电子迁移常数5.37×10~(-6)cm/s.修饰电极能够催化H_2O_2的电还原,还原峰电流与H_2O_2浓度在2.0×10~(-6)～2.0×10~(-4)mol/L范围呈线性关系,相关系数R=-0.99042,可用于H_2O_2的电催化检测.     

2,6-二(5-甲基噁二唑)吡啶的电化学性质及离子识别性能研究

用循环伏安法和计时电量法等电化学方法研究了配体2,6-二(5-甲基噁二唑)吡啶(DMOP)在玻碳电极(CCE)上的电化学行为.结果表明:在-0.3～-1.3 V电位范围内及0.1 mol/L四丁基高氯酸铵(TBAP)的N,N-二甲基甲酰胺底液中,DMOP于-0.8 V(vs.SCE)左右处产生一对准可逆的氧化还原峰,还原峰电流和氧化峰电流与扫描速率的平方根(v1/2)呈良好的线性关系,表明DMOP在GCE上的伏安行为是一受扩散控制的电化学过程,其电极反应过程是单电子转移,传递系数α为0.56,扩散系数为2.84×10-5 cm2/s,电极反应速率常数Kf为0.89 cm/s.利用循环伏安法研究了该化合物对过渡金属离子的识别作用,发现该化合物在一定浓度下对Pb2 有较好的选择识别性.     

羟胺在碳纳米管修饰玻碳电极上的电催化还原及电化学动力学性质研究

研究了羟胺在碳纳米管修饰玻碳电极(CNT/GC)上的电化学行为。研究结果表明,碳纳米管对羟胺的电化学行为有良好的电催化作用,在-0.62 V有一还原峰,是羟胺获得2个电子还原为铵所形成,同时测定了该电化学过程的动力学参数:电子转移数n为2,电子转移系数α为0.287,电极反应速率常数k为1.35×10-3cm/s。     

肉豆蔻酸-双层类脂膜修饰玻碳电极研究氯化血红素的电化学行为

报道了氯化血红素在肉豆蔻酸-双层类脂膜修饰玻碳电极上的电化学行为。在0.1~-0.7 V(vs.Ag/AgCl)电位范围内,扫描速率为40 mV/s时,氯化血红素在-0.4 V处产生很灵敏的还原峰电流。于pH7.50.01 mol/L KH2PO4-Na2HPO4底液中,该氧化峰电流与氯化血红素浓度在7.32×10-9~1.57×10-6mol/L范围内呈良好线性关系。该电极可作为检测氯化血红素的新型的高灵敏度电化学生物传感器。     

酸性介质中碘离子在铂电极上的电化学氧化行为

采用循环伏安法研究了酸性介质中碘离子在铂电极上不同电位区间, 不同酸度下的电化学反应行为. 结果表明, 当极化电位较低(小于0.6 V(vs Hg/Hg2SO4))时, 碘离子在铂电极上发生2I--2e→I2电氧化反应, 反应产物通过I2+I-=I-3被进一步溶解, 整个反应属于E-C(electrochemical-chemical)模式. 电氧化过程中可以形成碘膜, 其也可以被碘离子溶解. 当极化电位升高至0.6 V(vs Hg/Hg2SO4)或以上时, 碘离子会直接电氧化为高价态碘化合物, I-+3H2O→IO-3+6H++6e, 而析出的碘膜并不发生再氧化反应; 在电化学还原过程中, 出现了两个还原峰, 分别对应于I2、I-3的还原反应; 在无碘膜时, 碘离子电氧化过程受溶液中碘离子的液相扩散步骤控制; 碘膜形成后, 主要受碘膜中碘离子的固相扩散控制; 酸度对于碘离子的电化学氧化过程有很大的影响, 其线性极化曲线的起峰电位及电流峰值电位均随酸浓度升高而负移.     

四磺酸酞菁铜—DDAB表面活性剂薄膜电极对卤代乙酸的电化学催化

四磺酸酞菁铜阴离子（ＣｕＰｃＴｓ＾４－）在水溶液中可借助离子交换进入阳离子表面活性剂双十二烷基二甲基溴化铵（ＤＤＡＢ）薄膜电极，从而形成ＣｕＰｃＴＳ＾４－－ＤＤＡＢ薄膜电极，循环伏安实验表明，在ＫＢｒ溶液中，该薄膜电极有一对良好的还原氧化峰，阴阳极峤电位分别为－０．７８Ｖ和－０．６５Ｖ（ｖｓ．ＳＣＥ）．探讨了该薄膜电极的电化学行为，特别是对其各种卤代乙酸的电化学催化，对其机理进行了推测。     

Electrochemical properties of myoglobin deposited on multi-walled carbon nanotube/ciprofloxacin film

We report the direct electrochemical and electrocatalytic properties of myoglobin (MB) on a multi-walled carbon nanotube/ciprofloxacin (MWCNT/CF) film-modified electrode. A highly homogeneous MWCNT thin-film was prepared on an electrode surface using ciprofloxacin (CF) as a dispersing agent. MB was then electrochemically deposited onto the MWCNT/CF-modified electrode. The MB/MWCNT/CF film was characterized by scanning electron microscopy and UV-visible spectroscopy (UV-vis). UV-vis spectra confirmed that MB retained its original state on the MWCNT/CF film. Direct electrochemical properties of MB on the MWCNT/CF film were investigated by cyclic voltammetry. The formal potential and electron transfer rate constant were evaluated in pH 7.2 buffer solution as -0.327V and 300s(-1), respectively. In addition, the MB/MWCNT/CF-modified electrode showed excellent electrocatalytic properties for the reduction of hydrogen peroxide (H(2)O(2)). The MB/MWCNT/CF-modified electrode was used for the detection of H(2)O(2) at concentrations from 1×10(-6)M to 7×10(-4)M in pH 7.2 buffer solution. Overall, the MB/MWCNT/CF-modified electrode was very stable and has potential for development as a H(2)O(2) sensor.     

Electropolymerization of iron tetra(<Emphasis Type="Italic">o</Emphasis>-aminophenyl)porphyrin from aqueous solution and the electrocatalytic behavior of modified electrode

Stable electroactive iron tetra(o-aminophenyl)porphyrin (FeTAPP) films are prepared by electropolymerization from aqueous solution by cycling the electrode potential between −0.4 and 1.0 V vs Ag/AgCl at 0.1 V s⁻¹. The cyclic voltammetric response indicates that polymerization takes place after the oxidation of amino groups, and the films could be produced on glassy carbon (GC) and gold electrodes. The film growth of poly(FeTAPP) was monitored by using cyclic voltammetry and electrochemical quartz crystal microbalance. The cyclic voltammetric features of Fe(III)/Fe(II) redox couple in the film resembles that of surface confined redox species. The electrochemical response of the modified electrode was found to be dependent on the pH of the contacting solution with a negative shift of 57 mV/pH. The electrocatalytic behavior of poly(FeTAPP) film-modified electrode was investigated towards reduction of hydrogen peroxide, molecular oxygen, and chloroacetic acids (mono-, di-, and tri-). The reduction of hydrogen peroxide, molecular oxygen, and dichloroacetic acid occurred at less negative potential on poly(FeTAPP) film compared to bare GC electrode. Particularly, the overpotential of hydrogen peroxide was reduced substantially. The O₂ reduction proceeds through direct four-electron reduction mechanism.     

表面活性剂对聚氯乙烯膜修饰电极电化学行为的影响

采用循环伏安法考察了所制备的聚氯乙烯(PVC)膜修饰电极的稳定性,结果表明,该修饰电极性能稳定,电极反应过程为扩散控制的过程。以循环伏安法、计时库仑法、稳态极化曲线法和交流阻抗法分别考察了阳离子(十六烷基三甲基溴化铵,CTMAB)、阴离子(十二烷基硫酸钠,SDS)和非离子(脂肪醇聚氧乙烯醚,AEO9)3种不同类型的表面活性剂对PVC膜-Ag[B(ph)4]修饰电极反应过程的影响。结果表明:加入CT-MAB或SDS后,PVC膜中Ag[B(ph)4]氧化态和还原态的扩散系数分别比电极在0.1mol/LKOH支持电解质中的扩散系数小,PVC膜修饰电极的反应过程受扩散控制的特征变得更明显,表明在此条件下膜中的电子转移速度加快,CTMAB或SDS对PVC膜修饰电极的电极反应过程有增敏作用。而加入AEO9后,PVC膜中的Ag[B(ph)4]氧化态和还原态的扩散系数比电极在0.1mol/LKOH支持电解质中的扩散系数大,并使电极反应的控制步骤从扩散控制转向含电子转移控制的扩散控制,表明在此条件下膜中的电子转移速度变慢,AEO9对PVC膜修饰电极的电极反应过程有抑制作用。     

Direct Electrochemistry of Cytochrome c on a Silica Sol‐Gel Film Modified Electrode

Dilute silica sol‐gel was simply dropped on the surface of a basal plane graphite electrode (BPGE) to form a silica sol‐gel film modified electrode. Direct electrochemical response of cytochrome c (Cyt c) on the modified electrode was observed by cyclic voltammetry (CV). The results suggested that Cyt c could be tightly adsorbed on the surface of the silica sol‐gel film modified electrode. A couple of well‐defined and nearly reversible redox peaks can be observed in a phosphate buffer solution (pH 7.0), which anodic and cathodic peak potentials were at ?0.243 and ?0.306 V (vs. Ag/AgCl), respectively. Cyt c adsorbed on the surface of silica sol‐gel film shows a remarkable electrocatalytic activity for the reduction of oxygen. Based on these, a third‐generation biosensor could be constructed to detect the concentration of oxygen in aqueous solution.     

The electrochemical polymerization of redox dye-nile blue for the amperometric determination of hemoglobin

A semi conducting polymer-modified glassy carbon electrode was fabricated by cyclically sweeping in the potential range of −0.4–1.2 V(vs. SCE) or by electrolyzation at constant potential of 1.4 V in 0.5 M sulfuric acid solution containing 1.0 mM Nile Blue. This redox active polymer could successfully be used for the amperometric determination of hemoglobin. The effect of pH was studied for the polymerization of Nile Blue. It was found that the polymerization did not occur in neutral or basic solutions. The formal potential of this film is −410 mV (pH 7.0) which is more negative than that obtained at the bare electrode in the Nile Blue bulk solution. The electrochemical characteristics of this polymer are discussed. The modified electrode could electrocatalyze the reduction of hemoglobin, and a good linear amperometric response could be obtained over the range of 0.05–7.0 mg/mL (correlation coefficient: 0.985). This modified electrode exhibited good stability and reproducibility for long-term use.