酞菁钴及其衍生物修饰电极对分子氧的电催化还原

在玻碳电极上采用吸附法制备了四溴代酞菁钴(CoPcBr₄)、酞菁钴(CoPc)和四-α-(2,2,4-三甲基-3-戊氧基)酞菁钴(CoPc(OC₈H₁₇)₄)修饰电极。利用循环伏安法和线性扫描伏安法研究了修饰电极在酸性介质中对分子氧的电催化还原,比较了不同取代基的酞菁钴对电催化性质的影响。结果表明,它们对分子氧还原均具有良好的电催化活性,其中酞菁钴和四-α-(2,2,4-三甲基-3-戊氧基)酞菁钴对O₂的催化是2电子还原生成H₂O₂,与裸电极相比,O₂的还原峰电位分别向正方向移动了0.33和0.48 V。而四溴代酞菁钴修饰电极在-0.1和-0.7 V附近产生的2个还原峰,说明它催化O₂到H₂O₂的还原以后还可以促进H₂O₂继续还原到H₂O,最终实现O₂的4电子还原。     

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。     

Eu(Ⅲ)、Tb(Ⅲ)双酞菁配合物的合成及其LB膜的荧光性

稀土双酞菁配合物;Eu(Ⅲ)、Tb(Ⅲ)双酞菁配合物的合成及其LB膜的荧光性     

聚血红素修饰电极上氧还原的电催化研究

 采用循环伏安法和电位阶跃法,研究了水溶液中溶解氧在聚血红素修饰电极上还原反应的电催化作用．结果表明,还原峰电流随扫描速度的增大而增强,Ip～v1／2呈线性关系．根据电位阶跃实验的I～t曲线,计算出电极反应的电子转移数约为2,推断其催化机理属于ECE催化过程．     

CO2电催化还原的研究(Ⅲ)——TPP、TMAP、TMAPI系列金属卟啉的电催化活性

由于CO₂电催化还原有较高的电流效率、较低的过电位和较高的能量转换效率、因而倍受人们的注意。我们系统地研究了以TPP、TMAP和TMAPI为配体的配合物对CO₂电催化还原的活性,这对于开发CO₂的综合利用无疑是有意义的。     

酞菁钴－高分子双层膜修饰电极对氧的催化电还原

酞菁钴－高分子双层膜修饰电极对氧的催化电还原董国孝，李纪生，庄瑞舫（中国科学院北京化学研究所，北京，１０００８０）（南京大学配位化学研究所）关键词酞菁合钴，双层膜修饰电极，电还原金属酞菁配合物的催化活性和电催化活性已引起化学家们的极大兴趣，它们作为电...     

异菸肼在吸附型过渡金属酞菁配合物化学修饰电极上的电催化氧化

合成了一系列过渡金属的3,3,′3,″3(?)-四硝基酞菁配合物,用不可逆吸附法制备了它们的以玻碳为基体的化学修饰电极(简记为ML CME,M为金属离子,L为酞菁配体).用CV等方法系统地研究了它们的电化学性质特别是电催化性能,本文报道ML CME(M为Fe~(Ⅱ)、Co~(Ⅱ)、Ni~(Ⅱ)和Cu~(Ⅱ))对异菸肼氧化的电催化作用.     

甘氨酸修饰的Pt(111)电极上的氧还原

利用单晶旋转圆盘电极技术（Hanging Meniscus Rotating Disk Electrode,　HMRD）在硫酸和高氯酸溶液中分别研究了甘氨酸修饰的Pt(111)电极表面氧分子的电催化还原反应. 实验发现：在硫酸溶液中,经甘氨酸修饰的Pt(111)电极表面的氧还原活性明显提高,其中氧还原的半波电位与Pt(111)电极的相比正移约0.1 V,而在高氯酸溶液中,甘氨酸修饰的Pt(111)电极的活性几乎没有发生变化. 该实验结果表明：甘氨酸修饰的Pt(111)电极一方面抑制了SO₄^2-在电极表面的吸附,另一方面又能在电极表面提供相邻的空位供氧分子吸附. 通过与文献中报道的CN^-修饰的Pt(111)电极上的氧还原结果的对比,可以推测甘氨酸修饰的Pt(111)电极表面氧还原活性提高是由于甘氨酸在Pt(111)表面可能先被氧化成CN^-后吸附在电极表面,进而促进了氧分子的电催化还原反应.     

聚四氨基钴酞菁膜修饰电极对甲巯咪唑的电催化氧化

用循环伏安法(CV)研究了聚四氨基钴酞菁(CoTAPc)膜修饰电极(p-CoTAPc CME)对甲巯咪唑的电催化氧化行为.在pH=2的缓冲溶液中,与未修饰玻碳电极(GC)相比,甲巯咪唑在p-CoTAPc CME(GC基体)上的氧化峰电位(Vpa)负移220 mV左右,峰电流(Ipa)变为原来的3倍多;还原峰电位(Vpc)正移大约223 mV,峰电流(Ipc)几乎变为裸电极时的6倍.同时,p-CoTAPc CME对甲巯咪唑的电催化氧化活性有很高的稳定性.     

天青I修饰电极的电化学性质及对血红蛋白的电催化还原

天青I修饰电极在pH=5.5的HAc-NaAc缓冲溶液中,在0.3～-0.7V电位范围内表现出可逆的氧化还原行为,其表面式量电位E^0'=-0.21V,表观电极反应速率常数k_s'=0.69s^-1,该电极对血红蛋白的还原过程具有良好的催化作用。实验结果表明,由电沉积构成的修饰电极较吸附法制备的修饰电极具有更好的稳定性。     

Electrocatalytic Reduction of Dioxygen at Carbon Paste Electrode Modified with a Novel Cobalt(III) Schiff's Base Complex

A carbon paste modified electrode with a new cobalt(III) Schiff's base complex (CPME) and its application to electrocatalytic activity for dioxygen reduction is developed. The electrochemical behavior and stability of the CPME as well as the two‐electron reduction of O₂ at the electrode were investigated using cyclic voltammetry, chronoamperometry and rotating disk electrode methods. At the CPME, the reduction of dioxygen to hydrogen peroxide occurs at potentials where it is not observed at a bare carbon paste electrode. The CPME exhibited potent and persistent electrocatalysis for O₂ reduction in acetate buffer solutions of pH 4.0 with an overpotential of about 800 mV lower than unmodified CPE and drastic increase in the peak current. The heterogeneous rate constant for the reduction of O₂ at the surface of CPME was determined by hydrodynamic voltammetry using the Koutecky–Levich plot. A possible catalytic mechanism is proposed and discussed.     

Microperoxidase-11 Modified Electrode and Its Electrocatalytic Activity on the Reduction of O2 and H2O2

Microperoxidase-11(MP-11) was immobilized on the surface of a silanized glass carbon electrode by means of the covalent bond with glutaraldehyde.The measurements of cyclic voltammetry demonstrated that the formal redox potential of immobilized MP-11 was -170mV.which is significantly more positive than that of MP-11 in a solution or immobilized on the surface of electrodes prepared with other methods.This MP-11 modified electrode showed a good electrocatalytic activity and stability for the reduction of oxygen and hydrogen peroxide.     

Electrocatalytic Activity of Riboflavin Chemically Modified Electrode Toward Dioxygen Reduction

Abstract

A chemically modified electrode (CME) exhibiting electrocatalytic response toward dioxygen was constructed by adsorbing the mediator riboflavin onto spectroscopic graphite. The electron transfer between the riboflavin functionality and the graphite was fast. The surface apparent coverage was at most 9.6 × 10^?10 mol cm^?2. The modified electrode permitted the dioxygen electroreduction to take place at the reduction potential of the mediator molecule. Dioxygen accepted two electrons from a reduced mediator to form hydrogen peroxide. Characterisation of the performance of the CME was carried out. After 30 min of continuous electrochemical cycling of pH 6.8, 30% of the original coverage remained for the CME. The effect of the solution pH and temperature on the electrocatalytic activity of the CME for oxygen reduction was also investigated.     

NanoTiO2-CNT复合膜电极在DMF溶液中对糠醛的异相电催化还原

通过在乙醇中电化学溶解Ti金属阳极合成前驱体Ti(OEt)4和溶胶-凝胶法在Ti表面修饰一层纳米TiO2-碳纳米管(nanoTiO2-CNT)复合膜, 采用循环伏安和电解合成法研究了nanoTiO2-CNT复合膜电极在N, N-二甲基甲酰胺(DMF)中的氧化还原行为以及对糠醛(furfural)还原的电催化活性. 结果发现, nanoTiO2-CNT电极在阴极扫描时有两对氧化还原峰, 可逆半波电位E r1/2 分别为－1.27 V和－2.44 V(vs SCE, 扫描速度100 mV•s-1), 分别对应于TiO2/Ti2O3氧化还原电对的可逆电极过程和TiO2/Ti(OH)3电对的准可逆电极过程；在DMF电解液中nanoTiO2-CNT复合膜中的Ti(IV)/Ti(III)氧化还原电对作为媒质间接电还原糠醛为糠醇, 反应机理为电化学偶联随后化学催化反应(EC′)机理.     

Cu(II) Hexacyanoferrate(III) Modified Carbon Paste Electrode; Application for Electrocatalytic Detection of Nitrite

Copper hexacyanoferrate (CuHCF) film‐modified carbon paste electrode (CPE) has been prepared from various electrolytic aqueous solutions using consecutive cyclic voltammetry. The cyclic voltammograms showed the direct deposition of CuHCF films from the mixing of Cu²⁺ and Fe(CN)₆^3? ions and each time with one of the six cations: H⁺, Na⁺, K⁺, NH₄⁺, Mg²⁺, and Al³⁺. The CuHCF film showed a single redox couple that exhibited a cation effect (Na⁺, K⁺, Mg²⁺, and NH₄⁺) and anion effect (Cl^?, NO₃^?, SO₄^2?, ClO₄^?, and BrO₃^?) in the cyclic voltammograms. Voltammetric studies have indicated that in presence of nitrite, the cathodic peak current of CuHCF increases, followed by a decrease in the corresponding anodic current. This indicated that nitrite was reduced by the redox mediator immobilized on the electrode surface via an electrocatalytic mechanism. The process of reduction and its kinetics were investigated by using cyclic voltammetry, differential pulse voltammetry, chronoamperometry and chronocoulometry techniques. The electrocatalytic ability about 800 mV can be seen. The rate constant of the catalytic reduction of nitrite was found to be 7.9×10⁵ cm³ mol^?1 s^?1. Linearity range obtained was 5×10^?5?8.4×10^?3 by cyclic voltammetry and 8×10^?6?1.3×10^?3 and 4×10^?3?2×10^?2 by differential pulse voltammetry.     

吡咯氮配位单原子铜催化剂的电催化二氧化碳还原性能

采用温度控制的浸渍-热解法, 合成了以碳纳米管为载体的一系列铜单原子催化剂. 扩展X射线吸收精细结构(EXAFS)分析表明, 催化剂中的单原子铜位点分别由吡啶氮和吡咯氮配位. 电催化性能测试表明, 所制备催化剂可用于电催化二氧化碳生成一氧化碳, 由吡啶氮配位的铜单原子催化剂的反应选择性较差, 而由吡咯氮配位的铜单原子催化剂则具有更强的活性, CO法拉第效率在-0.70 V(vs. RHE)时可达到96.3%; 吡咯氮配位的铜单原子中心对于析氢反应具有更好的抑制效果.     

稀土配合物的发光特性及其能量传递研究

利用激光诱导荧光技术研究了稀土铕等金属配合物的发光特性及其能量传递动力学过程．得到了这些稀土配合物中中心离子Eu（3 ）的激发光谱，配体的三线态发时光谱和单线态发射光谱；在实验上观察到由于中心离子Eu（3 ）的5D2←7F0马跃迁吸收造成的配体发射光谱中的凹陷行为     

Electrocatalytic Characteristics of Hydrazine and Hydroxylamine Oxidation at Coumestan Modified Carbon Paste Electrode

A coumestan derivative modified carbon paste electrode (CMCPE) was used as a sensitive electrochemical sensor for determination of electrocatalytic of hydrazine and hydroxylamine. The mechanism of electrocatalytic oxidation of both hydrazine and hydroxylamine using CMCPE was investigated by cyclic voltammetry and polarization studies. The kinetic parameters such as the electron transfer coefficient, α, heterogeneous rate constant, k′, and exchange current density, j₀, for oxidation of hydrazine and hydroxylamine at the CMCPE surface were determined using cyclic voltammetry. Further more, the linear dynamic range, sensitivity and limit of detection for hydrazine and hydroxylamine detections were evaluated using differential pulse voltammetry.     

Electrocatalytic Oxidation and Determination of Nitrite at Multi‐walled Carbon Nanotubes Modified Carbon Ceramic Electrode

In the present work, the electrochemical oxidation of nitrite on carbon ceramic electrode (CCE) modified with multi‐walled carbon nanotubes (MWCNTs) was investigated. The modified electrode exhibited catalytic activity toward the electrooxidation of nitrite. Experimental parameters such as solution pH, scan rate, concentration of nitrite and nanotubes amount were studied. It was shown nitrite can be determined by differential pulse voltammetry (DPV) and hydrodynamic amperometry (HA) using the modified electrode. Under the optimized conditions the calibration plots are linear in the concentration ranges of 15‐220 and 50‐3000 μM with limit of detections of 4.74 and 35.8 μM for DPV and HA, respectively. The modified electrode was successfully applied for analysis of nitrite in spinach sample. The results were favorbly compared to those obtained by UV‐Visible spectrophotometric method. The results of the analysis suggest that the proposed method has promise for the routine determination of nitrite in the examined products.     

A Simple and Efficient Electrochemical Sensor for Electrocatalytic Reduction of Nitrite Based on Poly(4‐aminoacetanilide) Film Using Carbon Paste Electrode

In this study, the electrochemical reduction of nitrite was investigated on poly(4‐aminoacetanilide) (PPAA) forming by cyclic voltammetry at the surface of carbon paste electrode. The electrochemical properties of the modified electrode have been studied by cyclic voltammetry and double potential step chronoamperometry. Results showed that in the optimum condition (pH = 0.00) the reduction of nitrite occurred at a potential about 667 mV more positive than that unmodified carbon paste electrode. This amount of electrocatalytic ability is high compared with other electrocatalysts. Using a chronoamperometric method, the catalytic rate constant (k) was calculated 8.4 × 10⁴ cm³ mol^‐1 s^‐1. Also, the electrocatalytic reduction peak currents was found to be linear with the nitrite concentration in the ranges of 5 × 10^‐4 M to 2.5 × 10^‐2 M and 2 × 10^‐5 M to 7 × 10^‐3 M with detection limits (2σ) were determined as 4.5 × 10^‐4 M and 1 × 10^‐5 M by cyclic voltammetry (CV) and hydrodynamic amperometry methods respectively. Recovery experiments exhibit the satisfactory results.