Ta/BDD薄膜电极电化学催化氧化硝基酚

研究了热丝化学气相沉积法(HFCVD)制备得到钽衬底掺硼金刚石膜电极(Ta/BDD)的物理性质和电势窗口, 并考察了其用于电化学催化氧化硝基酚过程中的性能及各种影响因素. 扫描电镜和拉曼光谱表明, Ta/BDD电极具有良好的物理性能, 通过测试Ta/BDD电势窗口发现, 该电极具有较高的析氧过电位. 在Ta/BDD电化学催化氧化硝基酚过程中, 化学需氧量(COD)和高效液相色谱测试表明, 硝基酚能够有效降解, 电流密度、支持电解液及浓度对降解过程影响较大, 温度影响不明显. 强化寿命实验表明, Ta/BDD电极具有较好的稳定性. 实验结果表明, Ta/BDD电极是一种适于硝基酚降解和COD去除的优良电极.     

邻苯二甲酸二甲酯在三维多孔钛基掺硼金刚石薄膜电极上的电催化氧化行为

以邻苯二甲酸二甲酯(DMP)作为模型污染物,研究了不同结构的钛基体对掺硼金刚石薄膜(Ti/BDD)电极电催化性能的影响.结果表明,三维多孔电极为氧化还原反应提供了更多的反应活性位点,表现出更快的电子传递速率.通过循环伏安法和线性扫描法验证了DMP在BDD电极上的电催化氧化行为属于直接电氧化过程,且在低浓度下近似为一级反应,DMP浓度较高时会在BDD电极表面发生成膜现象.在不同浓度的DMP溶液中使用平板Ti/BDD电极及多孔Ti/BDD电极进行直接电催化氧化时,DMP的电催化氧化过程与理论推断一致;多孔电极由于其电活性面积的优势在COD和DMP的去除方面均优于平板电极.     

掺硼金刚石电极电催化氧化酚类有机物的取代基效应

本文主要以当前水环境中存在酚类有机污染物为研究对象,探讨酚类有机污染物在掺硼金刚石(BDD)电极上的取代基效应,具体研究具有不同位置及种类官能团的取代酚类有机污染物在BDD电极上的电催化氧化过程,通过化学需氧量和浓度变化考察有机污染物在电催化降解过程中的降解趋势,深入分析电极种类、官能团位置与种类与电催化氧化活性之间的联系的同时,研究阳极材料电催化氧化有机污染物的机理及动力学。结果表明,有机物在电极表面的电催化过程以电产生羟基自由基为媒介,对苯二酚在不同电极上的电催化活性与电极析氧电位及表面产生羟基自由基量有着重要的联系,BDD电极拥有最强的电催化氧化活性;不同取代基团的对位取代酚在BDD电极上的电化学降解实验显示电催化反应速率受取代官能团自身的电子效应制约,有机物矿化过程中羟基自由基首先进攻苯环的对位发生取代反应,同时取代基脱离苯环过程成为整个取代酚类电化学降解过程的决速步骤,且有机物的电催化反应速率与取代基特征Hammett常数σ呈近似线性关系。     

多孔钛基掺硼金刚石电极结构对电催化降解阿司匹林性能的影响

利用扫描电子显微镜(SEM)和X射线衍射仪(XRD)对多孔Ti/BDD电极及传统平板Ti/BDD(BDD=钛基掺硼金刚石)电极进行了研究,通过循环伏安法考察了电极的背景电流和电化学窗口.以阿司匹林为模型污染物,研究了BDD电极结构对阿司匹林电催化降解的影响.结果表明,多孔Ti/BDD电极的总带电量,内、外部带电量,孔隙率和比表面积均高于平板Ti/BDD电极;多孔Ti/BDD在对COD和阿司匹林的去除率和能量消耗等方面均优于平板Ti/BDD电极.     

掺硼金刚石膜电极表面产生羟基自由基的原位ESR研究

建立了原位电化学-电子顺磁共振(ESR)方法,系统研究了掺硼金刚石(BDD)膜电极表面在水溶液中的羟基自由基(·OH)产生规律.结果表明,在高于析氧电位时,·OH的生成速率随着阳极电位的升高、电流密度的增加而增大,增加速率逐渐减缓.与此同时,与氢终端的BDD膜电极相比,氧终端的BDD膜电极表面因具有较好的亲水性而具有更高的·OH产生能力.在电化学氧化处理有机废水的过程中,电极表面处于氧终端的状态,有利于·OH产生并保持较高的活性.溶液pH值也在一定程度上影响·OH生成反应,酸性溶液中,BDD膜电极表面的·OH产生能力强于在中性或碱性溶液中.进一步研究发现,BDD膜电极表面还可能生成O3-·0自由基.本研究为深入探索BDD膜电极表面·OH的产生机制提供了研究手段,为阐述BDD膜电极电极在污染物处理中高效性的本质提供了有效的证据.     

苏丹红I号在纳米金/碳球修饰硼掺杂金刚石电极上的电化学行为

采用纳米金/碳球(Au/CS)复合物修饰硼掺杂金刚石(BDD)电极,研究了苏丹红I号在Au/CS修饰BDD电极上的电化学行为,并据此建立了实际样品中的苏丹红I号的测定方法.结果表明,与裸BDD电极相比,苏丹红I号在Au/CS修饰BDD电极上的氧化峰电流由0.24μA增加到0.83μA,峰电位由0.809V负移到0.743V.在最优测试条件下,苏丹红I号浓度与其峰电流在4~100μmol/L范围内呈线性关系,线性方程为Ip=0.011 26c+0.116(R2=0.999),检出限为8.33μmol/L.采用本方法对实际样品中的苏丹红I号进行测定,测定结果及平均回收率均优于BDD电极法.     

阿昔洛韦在硼掺杂金刚石电极上的电化学行为及其与DNA相互作用的研究

利用硼掺杂金刚石(BDD)电极通过循环伏安法和微分脉冲伏安法研究了阿昔洛韦在0.10 mol/L磷酸盐缓冲溶液(pH 7.4)中的电化学行为及其与DNA的相互作用.与玻碳电极相比,阿昔洛韦在BDD电极上的循环伏安曲线在1.17 V处的氧化峰电流更大,背景电流较低.根据峰电位随溶液pH值和扫描速率的变化趋势考察了阿昔洛韦...     

热电极技术在电化学传感器中的应用

热电极技术是使用电流直接或间接加热微电极,通过控制施加电流的时间和大小来调节电极表面的温度。电极加热时可以只提高电极表面温度,而溶液的整体温度并不改变。由于温度对电化学反应速率、物质的扩散和对流均有影响,使用热电极技术可以减少背景噪音、提高检测的灵敏度与重现性。因此,热电极技术因其简单的加热设备、更高的检测灵敏度和更低的电极污染效应,在电化学分析领域引起了普遍关注。本文介绍了热电极技术的发展概况、工作原理、电极设计思路、电极温度的测量与控制、电极种类以及在电化学检测系统、电致化学发光检测系统、流动注射安培检测系统、毛细管电泳/芯片-电化学/电致化学发光检测系统中的相关应用。最后展望了该技术的发展趋势。     

掺硼金刚石电极的再生性清洗方法研究

掺硼金刚石电极(BDD)是一种化学和电化学稳定性高、不易吸附污染物的电极.但是多次重复检测较高浓度神经递质如多巴胺、羟色胺后,产生了电极污染.特别是经过表面改性的电极,其表面吸附物难以简单去除.以Fe(CN)3-/4-氧化还原对为探针,通过二次水、乙醇、异丙醇等不同液体超声清洗,发现异丙醇是较好的清洗剂.未改性电极表面...     

铁氰化镨修饰的电化学传感器的研制及其对半胱氨酸的测定

采用循环伏安法在PrCl3+K3Fe(CN)6溶液中于石墨电极表面电沉积铁氰化镨(PrHCF)薄膜,制备PrHCF修饰电极。对该修饰电极电化学的行为进行分析,包括扫描速度、K+浓度以及阴、阳离子对膜电极的影响。同时,以红外和XPS对膜进行了表征,IR谱图中氰基的伸缩振动峰证明了膜的存在;而XPS谱图中Fe2p1/2和Fe2p3/2能级的分裂说明了在成膜过程中Fe的价态发生变化,据此提出了可能的电聚合机理。同时,此修饰电极对半胱氨酸具有电催化氧化活性,并对其响应进行了研究。     

Comparison of Boron‐Doped Diamond and Glassy Carbon Electrodes for Determination of Procaine Hydrochloride

The electrochemical oxidation of procaine hydrochloride (PC?HCL, 2‐diethylaminoethyl 4‐aminobenzoate hydrochloride) was investigated at as‐deposited boron‐doped diamond (ad‐BDD) electrode, anodically oxidized BDD (ao‐BDD) electrode and glassy carbon (GC) electrode using cyclic voltammetry (CV). Well‐defined cyclic voltammograms were obtained for PC?HCL oxidation with high signal‐to‐background (S/B) ratio, low tendency for adsorption, good reproducibility and long‐term stability at ad‐BDD electrode, demonstrating its superior electrochemical behavior and significant advantages in contrast to ao‐BDD and GC electrode. At 100 μM PC?HCL, the voltammetric S/B ratio was nearly one order of magnitude higher at an ad‐BDD electrode than that at a GC electrode. In a separate set of experiments for oxidation of 100 μM PC?HCL, 96%, 92% and 84% of the initial oxidation peak current was retained at the ad‐BDD, ao‐BDD and GC electrode, respectively, by stirring the solution after the tenth cycle. The current response was linearly proportional to the square root of the scan rate within the range 10–1000 mV s^?1 in 10 μM PC?HCL solutions, indicating that the oxidation process was diffusion‐controlled with negligible adsorption at an ad‐BDD surface. The good linearity was observed for a concentration range from 5 to 200 μM with a linear equation of y=0.03517x+0.65346 (r=0.999), and the detection limit was 0.5 μM for oxidation of PC?HCL at the ad‐BDD electrode. The ad‐BDD electrode could maintain 100% of its original activity after intermittent use for 3 months.     

金刚石薄膜电化学

金刚石由于其特殊的物理与化学性质,早在几百年前就吸引了人们对它的关注.化学气相沉积(chemical vapor deposition,CVD)法制备的高掺杂硼复合多晶金刚石薄膜,为金刚石薄膜在电化学中的应用开辟了新的领域.作为新型碳素电极材料,高掺杂硼复合多晶金刚石薄膜具有许多目前使用的电极材料所不可比拟的优异特性如:宽电化学势窗,低残留电流,极好的电化学稳定性以及表面不易被污染等.本文综述了高掺杂硼复合多晶金刚石薄膜电极在电化学中的几个重要应用,包括电分析、电合成及电化学法处理废水等.     

On the Utilization of Boron Doped Diamond Electrode as a Sensor for Parathion and as an Anode for Electrochemical Combustion Of Parathion

This work proposes the utilization of a boron doped diamond (BDD) electrode as a sensor for pesticides and as well as an anode for electrochemical combustion of Parathion in spiked, pure and natural waters. The square‐wave voltammetry was selected as the electroanalytical technique and the Britton–Robinson buffer as the electrolyte. The electrochemical reduction responses of Parathion were analyzed and compared with those previously obtained using a hanging mercury electrode (HMDE). The detection and quantification limits were calculated from the analytical curves both for BDD and HMDE in Milli‐Q water (2.4 and 7.9 μg L^?1 and 3.9 and 12.8 μg L^?1 respectively) showing only a slight improvement when used BDD. However, if the application involves polluted natural waters the improvement is accentuated due to the very low adsorption characteristics of BDD, which prevent the fouling of electrode surface by organic pollutants. The BDD was also used as anode for electrochemical remediation of Parathion contamination. In this case, electrolysis was carried out in high positive potential (3.0 V) and lead the electrochemical combustion of Parathion to CO₂ and H₂O, as measured by the diminishing of total organic carbon in the electrolyte.     

Sensitive Electrochemical Detection of Oxalate at a Positively Charged Boron‐Doped Diamond Surface

Allyltriethylammonium bromide (ATAB) was covalently attached to the surface of hydrogen‐terminated boron‐doped diamond (BDD) thin films using a photochemical method to fabricate positively charged electrode surfaces. The anodic current for oxalate oxidation both in cyclic voltammetry and in flow‐injection analysis with amperometry was found to be up to two times larger at ATAB‐modified BDD (ATAB‐BDD) than at an unmodified BDD electrode, which may be based on the electrostatic interaction between the oxalate anion and the electrode surface. In addition, the stability of the electrochemical detection of oxalate was improved at the ATAB‐BDD electrode compared to the unmodified electrode.     

Anodic Oxidation Behaviors of Formaldehyde at Boron‐Doped Diamond Electrodes

The electrochemical behaviors of formaldehyde (FA) at boron‐doped diamond (BDD) electrodes are investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and linear scanning voltammetry (LSV) techniques. The CV results show that the oxidation reaction of FA is influenced by the hydroxyl concentration in the solution, and the peak current response with the FA concentration is linear at the range from 10 to 100 mM. The differential capacitance from EIS results indicate that the FA molecules adsorb at the BDD electrode surface at low potential (from 1.0 to 1.4 V). The kinetic studies have been examined with the various concentrations of FA, pH, and temperature. The activation energy of FA oxidation is also calculated. The results of kinetic study indicate that the adsorption of FA molecules at the BDD electrode is the rate‐determining step at low potential (from 1.0 to 1.40 V).     

Fabrication of Pt nanoparticles-decorated CVD diamond electrode for biosensor applications

An electrochemical biosensor was developed using boron-doped diamond (BDD) as an electrode material. To enhance the electrical performance of the electrode, the BDD electrode was decorated with Pt-nanoparticles (Pt-NPs) by electrochemical deposition. Their morphology according to the applied potentials for the synthesis of Pt-NPs was characterized by SEM. To identify the performance of the electrode modified with Pt-NPs, glucose detection was used as a sample sensing process, and the results were compared with those of a gold electrode and a bare BDD electrode. The electrochemical characteristics of the modified electrode were examined by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The BDD electrode with the Pt-NPs showed higher sensitivity and a lower detection limit than the Au electrode and BDD electrode. The proposed biosensor based on the Pt-NPs decorated BDD electrode showed high sensitivity, a low detection limit, fast direct electron transfer and good stability.     

Electrochemical detection of ascorbic acid and serotonin at a boron-doped diamond electrode modified with poly(N,N-dimethylaniline)

The electrochemical oxidation of ascorbic acid (AA) and serotonin (5-HT) at a boron-doped diamond (BDD) electrode modified with poly(N,N-dimethylaniline) (PDMA) has been studied. The oxidation potentials of 5-HT and AA overlapped after mixing of the two chemicals, due to interference of AA at the bare BDD electrode. However, after modifying the BDD electrode with a cationic polymer (PDMA), the oxidation peaks of 5-HT and AA were separated. PDMA-coated BDD electrodes can be used for simultaneous detection of these species.     

pH sensing using boron doped diamond electrodes

The boron doped diamond (BDD) electrode is presented as an appropriate candidate for next generation glass-free, highly stable and accurate pH sensors. The method used in this study is based on the potential change related to the hydrogen evolution reaction following a current step, which is pH dependent. Alkali cations in the solution have no influence on the accuracy of the pH calibration curve, which provides an advantage with respect to the conventional pH glass electrode. The unwanted influence of electrochemically active compounds in solution can be avoided by adjusting the current density applied during chronopotentiometric measurements. The accuracy of the pH measurements is due to the excellent stability as well as the wide potential window and low background current of BDD electrodes. This faculty was not observed when using conventional electrode materials. The efficacy of this new type of pH sensor has been tested using tap water as a typical real sample.