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Benzene Oxidation on Boron-Doped Diamond Electrode: Electrochemical-Impedance Study of Adsorption Effects  [PDF]
Yuri Pleskov,Marina Krotova,Valerii Elkin,Valentin Varnin,Irina Teremetskaya
International Journal of Electrochemistry , 2012, DOI: 10.1155/2012/437063
Abstract: Benzene oxidation at a boron-doped diamond anode in 0.5？M K2SO4 aqueous solution is studied by cyclic voltammetry and electrochemical impedance spectroscopy. It is shown by measurements of differential capacitance and anodic current that in the ideal-polarizability potential region benzene either is not adsorbed at the diamond electrode or the benzene adsorption does not affect its capacitance. At more positive potentials, the adsorption of some intermediate of the benzene oxidation occurs at the electrode. The intermediate partially blocks the electrode surface and lowers the anodic current. The very fact of the electrode surface blocking is reflected in the complex-plane presentation of the impedance-potential plots. 1. Introduction Boron-doped diamond (BDD) proved being a corrosion-stable electrode material, particularly suitable for deep anodic oxidation [1]. Indeed, the diamond electrode makes it possible reaching high anodic potentials at which hydroxyl radicals (OH？) are formed at the anode surface (the oxygen evolution overpotential for diamond is sufficiently large, so this electrochemical reaction occurs with high current efficiency). The radicals oxidize organic and inorganic solutes (carboxylic acids, alcohols, phenols, aromatics) in the course of homogeneous chemical reaction. For this process, a kinetic model was suggested [2], according to which one of the two oxidation mechanisms is realized. In the potential region, where water is electrochemically stable, direct electron transfer occurs, whereas at high anodic potentials, indirect oxidation involving the above-mentioned hydroxyl radicals as mediator takes place (with concurrent oxygen evolution). The anodic oxidation at boron-doped diamond is an effective method of the nature and waste water purification from organic and inorganic pollutants [3, 4]. Benzene and its derivatives are typical water pollutants. The benzene oxidation at boron-doped diamond in 0.5？M H2SO4 solution was studied in [5]. It was shown by using high-performance liquid chromatography that a mixture of the benzene oxidation intermediates (hydroquinone, resorcinol, p-benzoquinone, catechol, and phenol) was formed in solution at the anode potential of 2.5？V (versus Ag/AgCl-electrode). The benzene complete incineration yielding CO2 occurs at potentials more positive than 2.5？V. In our preceding paper [6], the benzene oxidation at boron-doped diamond anode was studied in 1？M HCl solution by electrochemical impedance spectroscopy, with special emphasis on the revealing of the role of adsorption in the process. In this
Electrochemical oxidation of oxalic acid in the presence of halides at boron doped diamond electrode
Martínez-Huitle, C. A.;Ferro, S.;Reyna, S.;Cerro-López, M.;De Battisti, A.;Quiroz, M. A.;
Journal of the Brazilian Chemical Society , 2008, DOI: 10.1590/S0103-50532008000100021
Abstract: aim of this work is to discuss the electrochemical oxidation of oxalic acid (oa), analyzing the influence of nacl and nabr. experiments were carried out at boron-doped diamond (bdd) electrodes, in alkaline media. bdd electrodes have a poor superficial adsorptivity so their great stability toward oxidation allows the reaction to take place with reactants and intermediates in a non-adsorbed state. the process is significantly accelerated by the presence of a halogen salt in solution; interestingly, the mediated process does not depend on applied current density. based on the results, bromide was selected as a suitable mediator during oa oxidation at bdd. br- primarily acts in the volume of the solution, with the formation of strong oxidants; while cl- action has shown lower improvements in the oa oxidation rate at bdd respect to the results reported using pt electrode. finally, the parameters of removal efficiency and energy consumption for the electrochemical incineration of oa were calculated.
MODIFICATION OF BORON DOPED DIAMOND ELECTRODES WITH GLUCOSE OXIDASE, CHARACTERIZATION BY ELECTROCHEMICAL TECHNIQUES
DEL RíO,RODRIGO; ARMIJO,FRANCISCO; SCHREBLER,RICARDO; DEL CANTO,GABRIELA; VERGARA,CLAUDIA; GUTIERREZ,CESAR;
Journal of the Chilean Chemical Society , 2011, DOI: 10.4067/S0717-97072011000100022
Abstract: in this work, we report the effect of the direct successive modifications with glucose oxidase onto boron doped diamond electrode (bdd). the modification due to the enzyme adsorption, on the potentiodynamic response of the electrode, was evaluated using fe(cn)64-/3- red-ox couple on the electrolyte and the aep variations were related with the number of modifications. contact angle measurements and the electrochemical impedance spectra were also used to characterized the modifications and they showed variations in the same way that the potentiodynamic data.
MODIFICATION OF BORON DOPED DIAMOND ELECTRODES WITH GLUCOSE OXIDASE, CHARACTERIZATION BY ELECTROCHEMICAL TECHNIQUES  [cached]
RODRIGO DEL RíO,FRANCISCO ARMIJO,RICARDO SCHREBLER,GABRIELA DEL CANTO
Journal of the Chilean Chemical Society , 2011,
Abstract: In this work, we report the effect of the direct successive modifications with Glucose oxidase onto boron doped diamond electrode (BDD). The modification due to the enzyme adsorption, on the potentiodynamic response of the electrode, was evaluated using Fe(CN)6(4-/3-) red-ox couple on the electrolyte and the AEp variations were related with the number of modifications. Contact angle measurements and the electrochemical impedance spectra were also used to characterized the modifications and they showed variations in the same way that the potentiodynamic data.
Mechanism of Enhancement on Boron-doped Diamond Electrode Electrochemical Degradation Efficiency by Ultrasound
超声强化金刚石膜电极电化学降解效率的机制
SHEN Shi-hao,ZHAO Guo-hua,WU Mei-fen,LEI Yan-zhu,LIU Mei-chuan,
沈世豪,赵国华,吴梅芬,雷燕竹,刘梅川
环境科学 , 2008,
Abstract: Mass transport process, adsorption and desorption, and electrochemical reaction were analyzed to investigate the mechanism of enhancement on boron-doped diamond (BDD) electrode electrochemical degradation efficiency by ultrasound (US). US has considerable influences on the above steps of electrochemical oxidation. Mass transport coefficients of Ph and PA reach 2.010-5 m/s with US, from 5.410-6 m/s and 6.710-6 m/s in EC process, increasing by 270% and 199%, respectively. The effect of US on adsorption and desorption has relationship with electrochemical adsorption properties of pollutants on BDD electrode surface. The adsorption amount of Ph decreases from 6.4910-10 mol/cm2 to 1.3910-10 mol/cm2, with the desorption of polymer intermediates promoted, so US makes positive effect with benefit to direct oxidation and oxidation peak current increases by 32%. For PA, the adsorption amount decreases from 1.2510-11 mol/cm2 to 3.1110-12 mol/cm2 with US, and no direct oxidation happens in US-EC process. US can improve degradation efficiency of BDD electrode and the enhancement on Ph degradation is more effective. Average electrochemical oxidation energy efficiency (AEE) of Ph increases by 287%, more than 224% of PA. This is because both direct and indirect oxidation for Ph can be enhanced by US, while for PA, direct oxidation almost disappears.
Sensitive Electrochemical Detection of Glucose at Glucose Oxidase-Cobalt Phthalocyanine-Modified Boron-Doped Diamond Electrode  [PDF]
Takeshi Kondo,Masaru Horitani,Makoto Yuasa
International Journal of Electrochemistry , 2012, DOI: 10.1155/2012/943957
Abstract: Electrochemical detection of glucose was achieved at a glucose oxidase (GOx)-cobalt phthalocyanine (CoPc)-modified boron-doped diamond (BDD) electrode without any additional electron mediator in the electrolyte solution. The surface of the hydrogen-terminated BDD thin film prepared by microwave plasma-assisted CVD was modified with 4-vinylpyridine (4VP) via photochemical modification. The 4VP-BDD was then immersed in a CoPc solution to obtain CoPc-BDD. A poly(p-phenylenediamine) (PPD) thin film containing GOx was coated on the CoPc-BDD electrode surface via electropolymerization. At the GOx/PPD-CoPc-BDD electrode, anodic current for glucose oxidation was observed with a sigmoidal voltammetric curve, indicating successful electron mediation of H2O2 generated as the result of glucose oxidation at GOx. The signal-to-background ratio for voltammetric current of glucose detection was larger at the GOx/PPD-CoPc-BDD electrode than at the GOx/PPD-modified platinum electrode due to the smaller background current of the modified BDD electrode. 1. Introduction Highly boron-doped diamond (BDD) electrodes have been known to be a promising electrode material for sensitive electroanalysis based on the wide potential window and low background current as well as physical and chemical stability and biocompatibility [1]. Glucose is a compound, whose concentration is one of the most desired to be determined via electrochemical methods in relation to increasing demands for diabetes care [2]. In order to use BDD electrode for glucose detection, one should modify the surface with catalysts or enzymes due to the large overpotential for direct glucose oxidation at unmodified BDD electrodes. For glucose detection at BDD electrodes using electrocatalysts, Cu [3–5] and Ni [6–9] have been used for modification of the surfaces. Immobilization of particles or line patterns of these metals with micrometer or nanometer scale onto BDD surface enables sensitive glucose detection with low background current. On the other hand, BDD electrodes modified with glucose oxidase (GOx) [10–13] are advantageous because of their selectivity and sensitivity of the glucose molecule. In some cases, additional mediators, such as ferrocene carboxylic acid [11], were employed for glucose detection at GOx-modified BDD electrodes. Glucose detection without any additional reagents to samples is possible for simple analysis systems, and especially for monitoring concentration. Hydrogen peroxide is a product of glucose oxidation at GOx and thus can act as an electroactive mediator for electrochemical detection
Electrochemical Sensing and Assessment of Parabens in Hydro- Alcoholic Solutions and Water Using a Boron-Doped Diamond Electrode  [PDF]
Ciprian Radovan,Dan Cinghit？,Florica Manea,Manuela Mincea,Codruta Cofan,Vasile Ostafe
Sensors , 2008, DOI: 10.3390/s8074330
Abstract: In this paper, the electrochemical behaviour of several parabens preservatives, i.e. esters of p-hydroxybenzoic acid, methyl-, ethyl- and propyl-4-hydroxybenzoates as methyl-, ethyl- and propyl-parabens (MB, EB, and PB), has been investigated at a commercial boron-doped diamond electrode (BDDE), especially in the anodic potential range, in both hydro-alcoholic and aqueous media. The cyclic voltammetric and chronoamperometric measurements yielded calibration plots with very good linearity (R2 between 0.990 and 0.998) and high sensitivity, useful for detection and analytical applications. The determination of the characteristics of individual compounds, of an “overall paraben index”, the assessment of the stability and the saturation solubility in water, and the amperometric sensing and determination in double distilled, tap and river water matrix of the relatively slightly soluble investigated parabens have been carried out using electrochemical alternative. Estimated water solubility was correlated with the octanol-water partition coefficient. Several ideas regarding stability and persistence of the presumptive eco-toxic investigated preservatives in the environment or water systems have been adjacently discussed.
Electrochemical Sensing and Assessment of Parabens in Hydro- Alcoholic Solutions and Water Using a Boron-Doped Diamond Electrode
Ciprian Radovan,Dan Cinghit？？？？,Florica Manea,Manuela Mincea
Sensors , 2008,
Abstract: In this paper, the electrochemical behaviour of several parabens preservatives, i.e. esters of p-hydroxybenzoic acid, methyl-, ethyl- and propyl-4-hydroxybenzoates as methyl-, ethyl- and propyl-parabens (MB, EB, and PB), has been investigated at a commercial boron-doped diamond electrode (BDDE), especially in the anodic potential range, in both hydro-alcoholic and aqueous media. The cyclic voltammetric and chronoamperometric measurements yielded calibration plots with very good linearity (R2 between 0.990 and 0.998) and high sensitivity, useful for detection and analytical applications. The determination of the characteristics of individual compounds, of an ￠ € overall paraben index ￠ € , the assessment of the stability and the saturation solubility in water, and the amperometric sensing and determination in double distilled, tap and river water matrix of the relatively slightly soluble investigated parabens have been carried out using electrochemical alternative. Estimated water solubility was correlated with the octanol-water partition coefficient. Several ideas regarding stability and persistence of the presumptive eco-toxic investigated preservatives in the environment or water systems have been adjacently discussed.
Electrochemical incineration of dimethyl phthalate by anodic oxidation with boron-doped diamond electrode
HOU Yining,QU Jiuhui,ZHAO Xu,LIU Huijuan,
环境科学学报(英文版) , 2009,
Abstract: The anodic oxidation of aqueous solutions containing dimethyl phthalate (DMP) up to 125 mg/L with sodium sulfate (Na2SO4) as supporting electrolyte within the pH range 2.0–10.0 was studied using a one-compartment batch reactor employing a boron-doped diamond (BDD) as anode. Electrolyses were carried out at constant current density (1.5–4.5 mA/cm2). Complete mineralization was always achieved owing to the great concentration of hydroxyl radical (.OH) generated at the BDD surface. The effects of pH, apparent current density and initial DMP concentration on the degradation rate of DMP, the specific charge required for its total mineralization and mineralization current efficiency were investigated systematically. The mineralization rate of DMP was found to be pH-independent and to increase with increasing applied current density. Results indicated that this electrochemical process was subjected, at least partially, to the mass transfer of organics onto the BDD surface. Kinetic analysis of the temporal change of DMP concentration during electrolysis determined by High Performance Liquid Chromatography (HPLC) revealed that DMP decay under all tested conditions followed a pseudo first-order reaction. Aromatic intermediates and generated carboxylic acids were identified by Gas Chromatography-Mass Spectrometry (GC-MS) and a general pathway for the electrochemical incineration of DMP on BDD was proposed.
The water decomposition reactions on boron-doped diamond electrodes
Suffredini, Hugo B;Machado, Sérgio A. S;Avaca, Luis A;
Journal of the Brazilian Chemical Society , 2004, DOI: 10.1590/S0103-50532004000100004
Abstract: the electrochemical processes occurring at both edges of the wide electrochemical window of the boron doped diamond (bdd) electrode were studied by polarization curves experiments to evaluate the apparent energy of activation for the rate determining step in each reaction. it was found that the hydrogen evolution reaction occurs by a volmer-heyrovsky mechanism with the first step being the rds. moreover, the apparent energy of activation calculated from the tafel plots presented a value as high as 150 kj mol-1, indicating the formation of the m-h intermediate that is characteristic for the volmer step. on the other hand, the apparent energy of activation for the oxygen evolution reaction was found to be 106 kj mol-1 suggesting that the rds in this mechanism is the initial adsorption step. in this way, it was demonstrated that the interaction between water molecules and the electrode surface is strongly inhibited on bdd thus justifying the extended potential window observed for this material.
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