Boron-doped Diamond Thin-film Electrodes Research Articles

Electrochemical Detection of Serotonin Using Conductive Diamond Electrodes

Abstract The electrochemical detection of serotonin with highly boron-doped diamond thin film electrodes was investigated by use of flow injection analysis (FIA) with amperometric detection. The voltammetric behavior of diamond indicated low background current and a low tendency to adsorb the oxidative products on the electrode surface, in comparison to the glassy carbon electrode. An experimental amperometric detection limit of 10 nM (0.2 pmol) was obtained for the FIA technique, demonstrating that diamond is a stable and sensitive electrode for serotonin determination.

Electroanalysis of dopamine and NADH at conductive diamond electrodes

Highly boron-doped diamond thin-film electrodes were examined for various possible applications in electroanalysis. Electrochemical oxidation of dopamine and NADH was investigated using cyclic voltammetry and chronoamperometry. Comparison experiments were performed using glassy carbon electrodes. Anodically treated diamond electrodes made it possible to determine dopamine selectively with high sensitivity in the presence of a large excess of ascorbic acid in acidic media. A detection limit of 50 nM was obtained using chronoamperometry. The treated electrodes were found to be stable for several months. Electrochemical oxidation of NADH was carried out at as-deposited diamond electrodes, with which very stable and reproducible cyclic voltammograms for NADH oxidation were obtained, unlike glassy carbon, at which a significant positive shift (∼200 mV) in the peak potential was observed within 1 h. The amperometric detection limit was found to be ∼10 nM. Interference of ascorbic acid was minimal using untreated electrodes when the concentration of ascorbic acid was comparable to the NADH concentration. Diamond microelectrodes small enough to consist of only one or two high quality microcrystals were fabricated in order to compare the electrochemical behavior with that of polycrystalline thin film electrodes, which contain large numbers of grain boundaries, at which non-diamond (sp2) carbon can exist. This work demonstrates the potential of diamond electrodes for electroanalytical applications.

Electrochemical Generation of Silver (II) at Boron-Doped Diamond Electrodes

Synthetic boron-doped diamond (BDD) thin film electrodes were tested for the electrogeneration of silver(II). In nitric acid, the kinetics of the silver(I)/silver(II) couple were studied by cyclic voltammetry. The results demonstrate that silver(II) can be produced with high current efficiency by silver(I) oxidn. at BDD electrodes. At low concn. of nitric acid and high concn. of silver(I), AgO is formed on the electrode surface. [on SciFinder (R)]

Electrochemical characteristics and applications of boron-doped polycrystalline diamond film electrodes

The electrochemical characteristics of boron-doped polycrystalline diamond thin film (BDF) electrode 4 × 4 mm2 in size were studied using cyclic voltammetry and potentiostatic method. The diamond clectrode exhibits adequate electrochemical activity and its response current changes linearly with K3Fe(CN)6 concentrations. The response current is proportional to the square root of the scan rate, reflecting mass transport controlled by planar diffusion. Stable mass transport can be quickly established within is. The BDF electrode provides good resolving power for the determination of lead and cadmium and gives satisfactory results in the analysis of pure water sample.

Synthetic semiconductor diamond electrodes: The comparative study of the electrochemical behaviour of polycrystalline and single crystal boron-doped films

Capacitance and potentiodynamic measurements were conducted on single crystal (homoepitaxial) and polycrystalline boron-doped diamond thin-film electrodes. The impedance characteristics and kinetic data in the Ce3+/4+ redox system, even if having a great deal of variability, appeared to be similar for the two kinds of diamond electrodes, whereas the kinetics of redox reactions on crystalline diamond and amorphous diamond-like carbon films differ significantly. These data in aggregate lead to a tentative conclusion that the electrochemical behaviour of polycrystalline diamond is determined by the diamond crystallites proper, rather than by the disordered carbon of the intercrystallite boundaries. The concentration of uncompensated acceptors in diamond was estimated from the linear and non-linear impedance data. The ways of presentation of Mott–Schottky plots for semiconductor electrodes are discussed for the case of frequency-dependent differential capacitance.

Observation of Electrochemical C60 Reduction of a Diamond Thin Film Electrode at Room Temperature

Abstract Highly conductive boron-doped diamond thin film electrodes were used for the first time to examine the cyclic voltammetric behavior of C60 reduction at room temperature as a demonstration of the relatively wide potential window in nonaqueous media. Five reduction peaks were observable on diamond electrodes at room temperature, while four reduction peaks were observed on Pt.

Oxidation of Azide Anion at Boron-Doped Diamond Thin-Film Electrodes

The oxidation of dissolved inorganic azide anion in aqueous media was investigated using high-quality, boron-doped diamond thin-film electrodes. Linear sweep and differential pulse voltammetry, along with flow injection analysis in the amperometric detection mode, were used to study the reaction at neutral pH as a function of the potential sweep rate, analyte concentration, and electrolyte composition. Comparison experiments were performed using polished glassy carbon. Azide undergoes an irreversible oxidation (1 e-/equiv) at both of these carbon electrodes, presumably with nitrogen as the primary product. A linear dynamic range of 3−4 orders of magnitude and a detection limit as low as 0.1 μM (4.3 ppb) at a S/N = 3 were observed for diamond in the voltammetric measurements. The flow injection analysis results for diamond indicated a linear dynamic range of 5 orders of magnitude and a detection limit of 8 nM (0.3 ppb) at a S/N = 3. The diamond response was generally reproducible from film to film, and the...

Underpotential Deposition of Cu on Boron-Doped Diamond Thin Films

The deposition of copper on boron-doped diamond thin-film electrodes was investigated. Three kinds of boron-doped diamond films were studied: a film deposited on a silicon wafer, a second grown on a tungsten substrate, and a third, similar to the first, but surface-amorphized (bombarded) by ion beam irradiation. The films were investigated by a number of techniques. Linear potential sweep experiments in 0.1 M H2SO4 + 0.001 M CuSO4 solution showed that, besides the peak due to bulk copper deposition, a “prewave” peak is present in the voltammogram of the first two electrodes and not in the third one. An electrochemical activation at negative potential was imperative for the appearance of the “prewave” peak. The amount of copper involved was less than 2% of a monolayer. The comparison between spectroscopic and electrochemical investigations leads to the interpretation that the “prewave” peak corresponds to an underpotential deposition of Cu on graphitic inclusions in the diamond electrode, or along the gra...

Peer Reviewed: Boron-Doped Diamond Thin-Film Electrodes

Peer Reviewed: Boron-Doped Diamond Thin-Film Electrodes

Flow Injection Analysis with Diamond Thin-Film Detectors

The viability of using polycrystalline, boron-doped diamond thin-film electrodes for the amperometric detection of ferrocyanide, ferricyanide, ethylamine, and ethylenediamine has been investigated for the first time. These redox reactions were studied by cyclic voltammetry, hydrodynamic voltammetry, and flow injection analysis with electrochemical detection (FIA-EC) at films without any prior surface pretreatment. The diamond films, 1−5 μm thick, were grown on conducting Si substrates at a dopant level of ∼1019 boron atoms/cm3. The detector performance was evaluated as a function of the linear dynamic range, sensitivity, limit of detection, response variability, and response stability. The results indicate that diamond films produce analytically useful responses for all these analytes in both the scanning and constant potential modes. Noteworthy are the observations that boron-doped diamond (i) can be used as a substrate for the detection of both oxidation and reduction reactions (e.g., ferro- and ferricy...

Synthetic semiconductor diamond electrodes: kinetics of some redox reactions

Linear-sweep voltammograms were recorded on boron-doped diamond thin-film electrodes in K 3Fe(CN) 6, K 4Fe(CN) 6, quinone, and hydroquinone solutions; transfer coefficients and rate constants for anodic and cathodic reactions were determined. The reaction rates were compared to the diamond samples' electrical characteristics measured by the impedance spectroscopy techniques. The polarization (faradaic) resistance of a redox reaction at its equilibrium potential was shown to be proportional to the specific resistance of diamond samples. Reaction rate constants for the quinone/hydroquinone system appeared to be significantly less than those for the Fe(CN) 6 3−/4− system.

Voltammetric and amperometric study of electrochemical activity of boron-doped polycrystalline diamond thin film electrodes

The electrochemical activity of boron-doped polycrystalline diamond thin film (BDF) electrodes was studied by using voltammetry to determine hexacyanoferrate(III/II) in KCl and HClKCl (pH = 1.3) solutions. The preliminary results were compared with those given by glassy carbon (GC) electrodes and proved that the BDF electrodes offered high sensitivity, good precision and extreme stability over a month period. The effects of pH and their ohmic resistance on response current of BDF electrodes were also studied.

Synthetic semiconductor diamond electrodes: elucidation of the equivalent circuit for the case of frequency-dependent impedance

Analysis of the frequency dependence of the impedance of boron-doped diamond thin film electrodes resulted in elucidation of their equivalent circuit. The latter generally comprises a frequency-independent capacitance (or a constant phase element) and a resistance, connected in parallel, with a series-connected “bulk” resistance. For electrodes whose impedance contains a constant phase element, a frequency-dependent Mott-Schottky plot enabled us to determine the flat-band potential. The constant phase element was shown to describe properties of the space charge region in diamond, rather than those of surface states. The behaviour of diamond electrodes is often affected by a series (“Helmholtz”) capacitance, which may be compared with the space charge capacitance of a semiconductor.

Electrochemical characterization of boron-doped polycrystalline diamond thin-film electrodes

The electrochemical characterization of boron-doped polycrystalline diamond thin-film (BDF) electrodes was studied using the anodic scan after concentrating lead in 0.1 mol/L KCl - 41 micromol/L Hg(NO(3))(2) and 0.1 mol/L KNO(3) - 0.01 mol/L HNO(3) - 41 micromol/L Hg(NO(3))(2); accumulation voltage was -0.90 V. The results obtained were compared with those given by glassy carbon (GC) electrodes and proved that the BDF electrodes offered high sensitivity, good precision and extreme stability over a 2-month period. These electrodes provided good resolving power for the determination of lead and cadmium and gave satisfactory results in the analysis of a pure water sample.

Cyclic Voltammetric Studies of Charge Transfer Reactions at Highly Boron-Doped Polycrystalline Diamond Thin-Film Electrodes

Cyclic voltammetry and ac impedance analysis were used to measure the background current response and capacitance of interfaces formed at as grown (untreated) boron-doped polycrystalline diamond thin-film electrodes in contact with aqueous electrolytes. The diamond films (∼1 cm 2 , 15 μm thick ; carrier concentration, ∼10 17 cm -3 ) were grown on conducting Si substrates by plasma-enhanced chemical vapor deposition. Cyclic voltammetry was also used to determine the charge transfer reactions of several redox analytes at as grown and chemically wet etched diamond thin-film electrodes and to study the effect of surface pretreatment, including Fe(CN) 6 3-/4- , IrCl 6 2-/3- , Ru(NH 3 ) 6 3+/2+ , dopamine, 4-methylcatechol, MV 2+/+/0 , and ferrocene. The electrochemical response exhibited by the films is explained using two models : (i) traditional electron transfer at a p-type semiconductor-electrolyte interface and (ii) electron transfer at a composite electrode composed of nondiamond carbon impurities contained within a diamond matrix such that k° nondiamond >> k° diamond.

Electrochemical characteristics of boron-doped polycrystalline diamond film electrodes

The electrochemical characteristics of boron-doped polycrystalline diamond thin film electrodes with 4×4 mm2 in size have been studied using cyclic voltammetry and a potentiostatic method. The diamond electrode exhibits adequate electrochemical activity and the response current changes linearly with the K3Fe(CN)6 concentrations. The response current is proportional to the square root of the scan rate, reflecting the mass transport controlled by planar diffusion. Stable mass transport was quickly established within 4 s. Good stability and reproducibility are attractive properties of the diamond electrode for sensor applications.

Electrochemical characterization of boron-doped polycrystalline diamond thin-film electrodes

Electrochemical characterization of boron-doped polycrystalline diamond thin-film electrodes

The electrochemical activity of boron-doped polycrystalline diamond thin film electrodes

The electrochemical activity of [open quotes]as grown[close quotes] boron-doped polycrystalline diamond thin film electrodes has been studied using cyclic voltammetry, chronoamperometry, and ac impedance without external illumination. The resistivity of these materials after doping is ca. 10 ohm-cm. The diamond electrodes possess a low double layer capacitance and a relatively high polarization resistance toward surface oxidation. Slow electrode kinetics are observed for Fe(CN)[sub 6][sup 3[minus]/4[minus]] at the [open quotes]as grown[close quotes] surface; however, the electrode response was observed to be extremely stable over a 2-month period as compared with freshly polished glassy carbon. The results suggest that diamond electrodes may have suitable properties as an electrode material for use in electroanalysis. 30 refs., 8 figs., 4 tabs.