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1.
Yu. V. Pleskov M. D. Krotova V. G. Ralchenko I. I. Vlasov A. V. Saveliev 《Russian Journal of Electrochemistry》2010,46(9):1063-1068
Electrochemical behavior of nanocrystalline diamond films grown in microwave plasma initiated in Ar-CH4-H2-N2 mixtures containing 30 to 90 vol % N2 is studied. Thin-film nanocrystalline-diamond electrodes grown at this high (30 to 90 vol %) N2 content in reactor behave as nearly metal-like: reaction in the [Fe(CN)6]3−/4− redox couple proceeds in a reversible manner. Generally, with the increasing of the N2 content in the reactor the electrochemical behavior of a “poor conductor” gives place to the metal-like one; in a sense,
the material’s electrochemical activity saturates and does not change beyond some critical value of the N2 content (∼30 vol %). This conclusion is substantiated by the study of Raman spectra of the nanocrystalline diamond films:
at this N2 content the diamond-graphite structure of the material is stabilized. 相似文献
2.
Yu. V. Pleskov M. D. Krotova V. G. Ralchenko A. V. Saveliev A. D. Bozhko 《Russian Journal of Electrochemistry》2007,43(7):827-836
Nitrogenated nanocrystalline diamond films with controlled conductivity are deposited from microwave plasma in CH4-Ar-H2-N2 gas mixtures. They are characterized using atomic force microscopy, Raman spectroscopy, and electrophysical measurements. Their electrochemical properties are studied by cyclic voltammetry and electrochemical impedance spectroscopy. Kinetic parameters of reactions in [Fe(CN)6]3-/4- redox system are determined. The character of electrode behavior is controlled by the degree on nitrogenation. With the increasing of the nitrogen content in the reaction gas mixture (from 0 to 25%), the potential window somewhat narrows, the background current increases, the reversibility of reactions in the [Fe(CN)6]3-/4- redox system increases. By and large, the transition occurs from the electrochemical behavior of a “poor conductor” to that of a metal-like electrode. 相似文献
3.
Yu. V. Pleskov M. D. Krotova V. P. Varnin I. G. Teremetskaya 《Russian Journal of Electrochemistry》2010,46(3):325-330
The effect of nondiamond (sp
2-) carbon admixture on the surface of polycrystalline boron-doped CVD-diamond electrodes on their electrochemical behavior
was studied by comparing the films grown under similar conditions, yet of different thickness. It is shown that with the decreasing
of the film thickness (hence, with the increasing of the nondiamond carbon content therein) its surface acquired electrochemical
activity: the transfer coefficients of reactions in the [Fe(CN)6]3−/4− redox system increased, the oxygen anodic evolution overvoltage decreased, the differential capacitance increased; on the
whole, the diamond electrode demonstrated increasingly better pronounced metal-like behavior. 相似文献
4.
Abolanle S. Adekunle Kenneth I. Ozoemena 《Journal of Solid State Electrochemistry》2008,12(10):1325-1336
Electrochemistry of edge-plane pyrolytic graphite electrodes (EPPGEs) modified with Aldrich single-walled carbon nanotubes
(SWCNTs) electro-decorated with metal (Ni, Fe and Co) and their oxides have been studied. The morphology and identity of the
metallic dispersions were examined by scanning electron microscopy and energy-dispersive spectroscopy. We show that SWCNTs
serve as efficient conducting carbon material for electronic communication between metal films and the underlying carbon electrode.
By using cyclic voltammetry and electrochemical impedance spectroscopy (EIS) techniques, it is proved that both EPPGE-SWCNT-Ni
and EPPGE-SWCNT-Fe exhibit comparable electrochemical response in buffered aqueous solution (pH 7.0) and towards electro-oxidation
of hydrazine in Na2SO4 solution. The impedance spectra of these SWCNT-metal hybrids were complicated and follow electrical equivalent circuit model
typical of adsorption-controlled charge transfer kinetics. Hydrazine impedance spectra exhibited inductive loop, characteristic
of Faradaic current being governed by the occupation of an intermediate state. On the other hand, the EIS data obtained in
a simple redox probe, [Fe(CN)6]3−/[Fe(CN)6]4−, showed that EPPGE-SWCNT and EPPGE-SWCNT-Ni followed electrical equivalent circuit models typical of partial charge transfer
or adsorption-controlled kinetics with some resemblance to the behaviour of electrolyte–insulator–semiconductor sensors. 相似文献
5.
Chaopeng Fu Haihui Zhou Huimin Wu Jinhua Chen Yafei Kuang 《Colloid and polymer science》2008,286(13):1499-1504
The nonaqueous ionic liquid (IL) microemulsions composed of 1-butyl-3-methylimidazolium tetrafluoroborate, Triton X-100, and
toluene were prepared and the electrochemical properties of the nonaqueous IL microemulsions were investigated in this paper.
It is shown that characteristics of the nonaqueous IL microemulsions such as electrical conductivity, electrochemical window,
and solubility are good, which indicate that the nonaqueous IL microemulsions can be used as electrolyte for electrochemical
research. The electrochemical properties of the nonaqueous IL microemulsions were researched by cyclic voltammetry (CV) and
electrochemical impedance spectroscopy methods using potassium ferricyanide as electroactive probe. It was found that the
reversibility was better and the peak current densities of CV were higher for the [Fe(CN)6]3−/[Fe(CN)6]4− electrode reaction in the nonaqueous IL microemulsions than those in IL. However, the electrochemical behavior of the probe
in the nonaqueous IL microemulsions with different microenvironments (oil-in-IL, IL-in-oil, and bicontinuous) was different.
The electrochemical property of the probe in the oil-in-IL microemulsion was the best, which was studied in detail. 相似文献
6.
Yeong-Tarng Shieh Tzu-Yu Yu Tzong-Liu Wang Chien-Hsin Yang Wei-Tung Liao 《Colloid and polymer science》2012,290(1):1-9
In this study, we modified carbon nanotubes (CNTs) by grafting with poly(ethylene glycol) (PEG) using the “grafting to” method.
The PEG-grafted CNT (CNT-g-PEG) was cast on indium tin oxide (ITO) electrode to investigate the electrocatalytic activity
of CNT to the redox reactions of the Fe(CN)63−/4−as a probe using cyclic voltammetry and electrochemical impedance spectroscopy. The electrocatalytic activity of CNT was correlated
with CNT dispersion in the cast film on ITO as a function of pH of aqueous solution from which the film was cast. The CNT
dispersions in aqueous solutions of different pH and in the cast films were examined by visual observation and zeta potential,
scanning electron microscopy and transmission electron microscopy, respectively. At a pH in the range of 3–11 at which ITO
electrode was modified, two functionalized CNT (fCNT and CNT-g-PEG) were both found to electrocatalyze the redox reactions
of the Fe(CN)63−/4−probe and the PEG grafts in CNT-g-PEG could help CNT adhere to the electrode to obtain durable modified electrode. The more
uniform CNT dispersions in aqueous solutions and in the cast films appeared to have greater electrocatalytic acitivity. 相似文献
7.
Sheng Liu Miao Chen JinDu Li HaoBo Zhang JinQing Wang ShengRong Yang 《中国科学B辑(英文版)》2009,52(7):1009-1013
Hybridization of peptide nucleic acids probe containing azobenzene (NH2-TNT4, N-PNAs) with DNA was performed by covalently immobilizing of NH2-TNT4 in sequence on the 3-mercaptopropionic acid self-assembled monolayer modified gold electrode with the helps of N-(3-dimethylaminopropy1)-N′-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS), and the hybrid was coded as N-PNAs/DNA. Using [Fe(CN)6]4−/3− (1:1) as the electrochemical indicator, the electrochemical properties of the N-PNAs self-assembled monolayer (N-PNAs-SAMs) and N-PNAs/DNA hybridization system under the conditions of before and after UV light irradiation were characterized with cyclic
voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectra (EIS). Results showed that the
redox currents decreased with the increase of irradiation time, suggesting that the ability of the charge transfer on the
electrode surface was weakened and the conformation of hybrid system had been changed, and the control of PNAs/DNA hybridization
could be realized by UV light irradiation.
Supported by the National Natural Science Foundation of China (Grant No. 50572107) and “Top Hundred Talents Program” of Chinese
Academy of Science 相似文献
8.
Yu. V. Pleskov Yu. E. Evstefeeva V. P. Varnin I. G. Teremetskaya 《Russian Journal of Electrochemistry》2004,40(9):886-892
Electrode behavior of homoepitaxial (single-crystal) boron-doped diamond films deposited onto differently orientated faces of dielectric diamond single crystals is studied by the electrochemical impedance and potentiodynamic curve methods. It is shown that the acceptor concentration determined from the slope of Mott–Schottky plots decreases, in the epitaxial films grown under the same conditions, in the series: (111) > (110) > (100). This is explained by different intensity of boron incorporation, from gas phase, into differently orientated faces of the diamond crystals during their growth. The rate of electrode reactions in the Fe(CN)6
3–/4– and Ru(NH3)6
2+/3+ redox systems decreases in the above series, which obeys the earlier found interrelationship between the electrochemical kinetics at diamond electrodes and their doping level. 相似文献
9.
The remarkable enhancement of electron transfer on screen-printed carbon electrodes (SPCEs) with modification by iron nanoparticles
(Fenano), coupled with Fe(CN)6
4−/3− redox species, was characterized with an increase of electroactive area (A
ea) at electrode surface together with a decrease of heterogeneous electron transfer rate constant (k°) in the system. Hence, Fenano-Fe(CN)6
3− SPCEs with deposition of glucose oxidase (GOD) demonstrated a higher sensitivity to various glucose concentrations than Fe(CN)6
3−/GOD-deposited SPCEs. In addition, an inhibited diffusion current from cyclic voltammograms was also observed with an increase
in redox concentration and complicated the estimation of A
ea. Further analysis by the electrochemical impedance method, it was shown that this effect might be resulted from the electrode
surface blocking by the products of activated complex decomposition. 相似文献
10.
[MoVIO2(S2C2(CN)2)2]2− (┘1) and [MoIVO(S2C2(CN)2)2]2− (2) mimick oxidoreductase enzymatic activities of sulphite oxidase with biological electron donor, SO
3
2−
, andin vitro electron acceptor, [Fe(CN)6]3−, demonstrating proton coupled electron transfer reaction in water and inhibition of the oxidation of (2) in the presence of KCN. The sulphite exidizing system is characterized by substrate saturation kinetics indicating the biological
significance of the reactions 相似文献
11.
Functionalized polypyrrole films were prepared by incorporation of Fe(CN)6
3− as doping anion during the electropolymerization of pyrrole at a glassy carbon electrode from aqueous solution. The electrochemical
behavior of the Fe(CN)6
3−/Fe(CN)6
4− redox couple in polypyrrole was studied by cyclic voltammetry. An obvious surface redox reaction was observed and dependence
of this reaction on the solution pH was illustrated. The electrocatalytic ability of polypyrrole film with ferrocyanide incorporated
was demonstrated by oxidation of ascorbic acid at the optimized pH of 4 in a glycine buffer. The catalytic effect for mediated
oxidation of ascorbic acid was 300 mV and the bimolecular rate constant determined for surface coverage of 4.5 × 10−8 M cm−2 using rotating disk electrode voltammetry was 86 M−1 s−1. Furthermore, the catalytic oxidation current was linearly dependent on ascorbic acid concentration in the range 5 × 10−4–1.6 × 10−2 M with a correlation coefficient of 0.996. The plot of i
p versus v
1/2 confirms the diffusion nature of the peak current i
p.
Received: 12 April 1999 / Accepted: 25 May 1999 相似文献
12.
Shen-Ming Chen Wen-Yan Chzo R. Thangamuthu 《Journal of Solid State Electrochemistry》2008,12(11):1487-1495
Electrochemically active hybrid coatings based on cationic films, didodecyldimethylammonium bromide (DDAB), and poly(diallyldimethylammonium
chloride) (PDDAC) are prepared on electrode surface by cycling the film-covered electrode repetitively in a pH 6.5 solution
containing Fe(CN)6
3− and Ru(CN)6
4− anions. Modified electrodes exhibited stable and reversible voltammetric responses corresponding to characteristics of Fe(CN)6
3−/4− and Ru(CN)6
4−/3− redox couples. The cyclic voltammetric features of hybrid coatings resemble that of electron transfer process of surface-confined
redox couple. Electrochemical quartz crystal microbalance results show that more amounts of electroactive anionic complexes
partitioned into DDAB coating than those doped into PDDAC coating from the same doping solution. Peak potentials of hybrid
film-bound redox couples showed a negative shift compared to those at bare electrode and this shift was more pronounced in
the case of DDAB. Finally, the advantages of hybrid coatings in electrocatalysis are demonstrated with sulfur oxoanions. 相似文献
13.
Marcin Opallo 《Journal of Solid State Electrochemistry》1998,2(5):347-354
The electrochemical redox reactions: Fe(CN)6
4−−e−↔ Fe(CN)6
3−, Ru(NH3)6
3++e−↔ Ru (NH3)6
2+ and Fc(CH2OH)2−e−↔ Fc(CH2OH)2
+ (Fc–ferrocene) were investigated in tetrabutylammonium halide hydrates at temperatures below and above the electrolyte melting
point. They were studied by cyclic voltammetry, potential step chronoamperometry and impedance spectroscopy. Freezing of
the electrolyte affects both the shape and position of the cyclic voltammogram on the potential scale. Also the shapes of
the current-time relationship and the impedance spectra change at temperatures below the melting point. It has been proposed
that this behaviour is caused by slow transport of the reactant and the heterogeneous nature of the electrolyte. The activation
energies of reactant transport are about four times larger in frozen electrolytes than those in liquid. It has been concluded
that reactant transport is restricted to the intergrain space of the electrolyte.
Received: 16 December 1997 / Accepted: 10 February 1998 相似文献
14.
The sorption of anions H2PO4
−, HPO4
2−, PO4
3−, [Fe(CN)6]3−, and [Fe(CN)6]4− from aqueous solutions on the surface of FeIII and ZrIV oxyhydroxide hydrogels freshly precipitated at pH 4–13 was studied. The region of sorbate concentrations was from 0.00025
to 0.06 mol L−1. The plots of the anion uptakes vs. their equilibrium concentrations are represented by isotherms of the first type, which are well described by the Langmuir
equation if the quantity of the amount adsorbed is expressed as mol-site g−1. The maximum uptakes and constants of the Langmuir equation were calculated. The phosphate anions occupy the same number
of sorption sites on the sorbents precipitated at different pH. The average specific content of sorption sites for the ferro-
and zirconogels in the metastability period is independent of the pH of their precipitation, being 3.1·10−3 and 3.2·10−3 mol-site g−1, respectively. The [Fe(CN)6]3− and [Fe(CN)6]4− anions are sorbed only on the positively charged sites of the hydrogels and occupy not more than 2·10 mol-site g−1 in the studied interval of pH of precipitation.
__________
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1736—1741, August, 2005. 相似文献
15.
Júlia Galandová Renáta Ovádeková Adriana Ferancová Ján Labuda 《Analytical and bioanalytical chemistry》2009,394(3):855-861
A screen-printed carbon working electrode within a commercially available screen-printed three-electrode assembly was modified
by using a composite of multiwalled carbon nanotubes (MWCNT) dispersed in polyethylenimine (PEI) followed by covering with
the calf thymus dsDNA layer. Several electrochemical methods were used to characterize the biosensor and to evaluate damage
to the surface-attached DNA: square wave voltammetry of the [Ru(bpy)3]2+ redox indicator and mediator of the guanine moiety oxidation, cyclic voltammetry and electrochemical impedance spectroscopy
in the presence of the [Fe(CN)6]3−/4− indicator in solution. Due to high electroconductivity and large surface area of MWCNT and positive charge of PEI, the MWCNT–PEI
composite is an advantageous platform for the DNA immobilization by the polyelectrolyte complexation and its voltammetric
and impedimetric detection. In this respect, the MWCNT–PEI interface exhibited better properties than the MWCNT–chitosan one
reported from our laboratory previously. A deep DNA layer damage at incubation of the biosensor in quinazoline solution was
found, which depends on the quinazoline concentration and incubation time.
Figure Impedance spectra for the modified electrodes. Conditions: 1 mM [Fe(CN)6]3–/4– in 0.1 M PBS (pH = 7.0), potential amplitude 10 m V, frequency range 12–1×104 Hz.
Dedicated to Professor Jan Garaj on the occasion of his 75th birthday 相似文献
16.
Yu. V. Pleskov M. D. Krotova V. I. Polyakov A. V. Khomich A. I. Rukovishnikov B. L. Druz I. M. Zaritskii 《Russian Journal of Electrochemistry》2000,36(9):1008-1013
The electrochemical impedance of thin-film electrodes made of amorphous nitrogen-containing diamondlike carbon (a-C:N:H) in
H2SO4 solutions and the kinetics of redox reactions on these electrodes in the Fe(CN)
6
3-/4-
system are studied. The amorphous diamondlike carbon films with an admixture of nitrogen are grown by a directed deposition
from inductively coupled methane-nitrogen plasma. The films’ resistivity values determined from the ac impedance of a-C:N:H/electrolyte
contact practically coincided with those determined from the current-vol.tage curves taken at the a-C:N:H/metal contact. With
an increase in the nitrogen : methane ratio in the gas phase, both the electrical resistance and optical bandgap decrease
from 3 x 1010 to 5 x 106 ohm cm and from 1.3 to 0.6 eV, respectively. Simultaneously, the concentration of electrically active point-defect centers
in a-C:N:H increases significantly and the reaction in the Fe(CN)
6
3-/4-
system is facilitated. 相似文献
17.
Bruna C. Lourencao Tiago A. Silva Hudson Zanin Paul W. May Evaldo J. Corat Orlando Fatibello-Filho 《Journal of Solid State Electrochemistry》2016,20(9):2403-2409
Porous boron-doped diamond (p-BDD) electrodes of high-surface-area have been prepared on vertically aligned carbon nanotube substrates, and their electrochemical performance has demonstrated promising results for application in electroanalysis. The electrochemical features of the p-BDD electrodes were investigated and compared with those of a conventional flat BDD electrode (f-BDD). From cyclic voltammetry studies performed for the electrochemical probes [Fe(CN)6]3? and N,N,N′,N′-tetramethyl-para-phenylenediamine (TMPD), a fast charge transfer was observed at the p-BDD/electrolyte interface. For the [Fe(CN)6]3? redox probe, the heterogeneous electron-transfer rate constant (k 0) value obtained for p-BDD was 10.9 times higher than that obtained using a f-BDD electrode. Moreover, the p-BDD electrodes also gave a smaller peak potential separation, ΔE p, and larger analytical signal magnitude for different biomolecules, such as dopamine (DA), acetaminophen (AC), and epinephrine (EP). These set of results demonstrated that the p-BDD electrode is a suitable candidate for applications in electroanalytical chemistry. 相似文献
18.
M. D. Krotova Yu. V. Pleskov A. A. Khomich V. G. Ralchenko D. N. Sovyk V. A. Kazakov 《Russian Journal of Electrochemistry》2014,50(2):101-107
The semiconductor properties of nitrogenated nanocrystalline diamond electrodes and their corrosion transformations caused by electrochemical experiment in indifferent electrolyte (1 M K2SO4) were studied by the electrochemical impedance spectroscopy method. It was shown that after electrochemical measurements a narrow diamond peak at 1335.7 cm?1 appears in the Raman spectrum; formerly the peak was hidden at a background of the intense signal inherent to graphite-like carbon. It was suggested that the corrosion damage caused by the exposure to electrochemical experiment resulted in a decrease of relative amount of nondiamond (graphite-like) carbon in the subsurface layer in the nanocrystalline diamond. By using Mott-Schottky plots, the nanocrystalline diamond was shown having n-type conductance. Within the bounds of the “effective medium” approach, the nanocrystalline diamond’s flat-band potential in aqueous solution and the noncompensated donor apparent concentration were estimated. 相似文献
19.
The iron(III) dimeric complex [Fe2(CN)10]4− is reduced to the iron(III)iron(II) species [Fe2(CN)10]5− by iodide ion, the equilibrium constant being strongly dependent upon the nature of the alkali metal cation, reduction being
favoured in the sequence: Cs+>NH
4
+
≥K+>Na+>Li+. The reaction kinetics are autocatalytic in character, the catalytic species being the mixed valence dimer. The rates of
reactions are also strongly catalysed by alkali metal cations, in the same sequence as for the equilibrium constants. The
reaction mechanism involves the formation of I
2
−
as a reactive intermediate which can be oxidised by both [Fe2(CN)10]4− and [Fe2(CN)10]5−. 相似文献
20.
Zusammenfassung Es wurden die elektrochemischen Eigenschaften des Redox-Systems K4[Fe(CN)6]-K3[Fe(CN)6] in Ameisensäure-Wasser-, Essigsäure-Wasser-, Propionsäure-Wasser- und n-Buttersäure-Wasser-Gemischen untersucht. Die Veränderungen des Redoxpotentials, der Leitfähigkeit und der Dielektrizitäts-konstante wurden studiert.Es wurde bewiesen, daß die Potentialveränderung des Redox-Systems bei kleiner Säurekonzentration (n
s<0,6–0,7) vor allem durch die Wasserstoffionen-Konzentration der Lösung bestimmt wird. Mit der Zunahme der H+-Konzentration nimmt die Aktivität des [Fe(CN)6]4– in größerem Maße ab als die des [Fe(CN)6]3–.Bei großer Säurekonzentration beeinflußt dagegen hauptsächlich die Anionsolvatation durch das Lösungsmittelgemisch die Verschiebung des Redoxpotentials. Die Solvatation ruft eine Strukturveränderung hervor, wodurch die Elektronen-population der Lösungsmittelmoleküle in der Nähe der Cyanoferrat-Ionen abnimmt, die Elektronen-Acceptor-Wirkung des Lösungsmittels wächst. Dieser Prozeß bewirkt in bekannter Weise die Zunahme des Redoxpotentials.
Mit 7 Abbildungen 相似文献
The electrochemical behaviour of redox systems in mixed solvents, II.: TheK 4[Fe(CN) 6]-K 3[Fe(CN) 6] system in fatty acid-water mixtures
The electrochemical behaviour of the K4[Fe(CN)6]-K3[Fe(CN)6] system has been investigated in mixtures of water with formic, acetic, propionic and n-butyric acid, resp. The change of the redox potential, the conductivity and the dielectric constant has been studied. It has been proved that the change of the redox potential of the system at low acid concentration (n s<0.6–0.7) is determined by the H+ concentration. Increasing the H+ concentration, the activity of the [Fe(CN)6]4– decreases in a higher extent than the activity of [Fe(CN)6]3–.On the other hand, at high acid concentration the shift in the redox potential is influenced first of all by the anion solvating effect of the solvent. The solvation causes such a change in the structure, that the electron population of the solvent molecules around the [Fe(CN)6]4– ions decreases, the acceptor strength of the solvent increases. It is well known that this process causes an increase in the redox potential.
Mit 7 Abbildungen 相似文献