共查询到20条相似文献,搜索用时 15 毫秒
1.
Regina M. Q. Mello José P. M. Serbena Adriano R. V. Benvenho Ivo A. Hümmelgen 《Journal of Solid State Electrochemistry》2003,7(8):463-467
We report the electrochemical preparation of poly(p-phenylene) (PPP) thin films with a polymerization degree of approximately 20 using biphenyl as starting material. The PPP
films are prepared directly on a tin oxide electrode, presenting a positive charge carrier mobility of 5×10−7 cm2 V−1 s−1. 相似文献
2.
Franco Varsano Francesca Decker Enrico Masetti 《Monatshefte für Chemie / Chemical Monthly》2001,132(1):83-95
Summary. Ce-V mixed oxide films have been deposited by RF sputtering with the aim of increasing the Li charge capacity of counter
electrodes in smart windows. Such mixed oxides have shown high transmittance and optical passivity in the visible region.
After electrode pre-conditioning by cyclic voltammetry, a good electrochemical reversibility in LiClO4– propylene carbonate electrolyte was observed, and large Li-charge capacity under galvanostatic charging (up to 50 mCċcm−2) has been measured. The electrode charge capacity decreased after prolonged insertion-deinsertion cycles, whereas the photoptic
transmittance remained about constant. After 800 cycles the Li-charge capacity decreased to 40 mCċcm−2. The Li diffusion coefficient inside the films measured by electrochemical impedance and by galvanostatic titration ranged
from 10−11 cm2ċs−1 to 10−13cm2ċs−1. We observed that the Li charge capacity of the film electrodes is a function of the film deposition conditions, because
it increased with the vanadium oxide concentration in the target and with the oxygen content in the sputtering atmosphere.
Received June 23, 2000. Accepted (revised) August 7, 2000 相似文献
3.
Franco Varsano Francesca Decker Enrico Masetti 《Monatshefte für Chemie / Chemical Monthly》2001,15(2):83-95
Ce-V mixed oxide films have been deposited by RF sputtering with the aim of increasing the Li charge capacity of counter electrodes in smart windows. Such mixed oxides have shown high transmittance and optical passivity in the visible region. After electrode pre-conditioning by cyclic voltammetry, a good electrochemical reversibility in LiClO4– propylene carbonate electrolyte was observed, and large Li-charge capacity under galvanostatic charging (up to 50 mCċcm−2) has been measured. The electrode charge capacity decreased after prolonged insertion-deinsertion cycles, whereas the photoptic transmittance remained about constant. After 800 cycles the Li-charge capacity decreased to 40 mCċcm−2. The Li diffusion coefficient inside the films measured by electrochemical impedance and by galvanostatic titration ranged from 10−11 cm2ċs−1 to 10−13cm2ċs−1. We observed that the Li charge capacity of the film electrodes is a function of the film deposition conditions, because it increased with the vanadium oxide concentration in the target and with the oxygen content in the sputtering atmosphere. 相似文献
4.
Igor Vrublevsky Vladimir Parkoun Vitaly Sokol Joachim Schreckenbach Werner A. Goedel 《Mikrochimica acta》2006,156(1-2):173-179
Chemical dissolution of the barrier layer of porous oxide films formed on an aluminum foil (99.5% purity) in 1.5 M sulfanic
acid after immersion in a 2 mol dm−3 sulphuric acid at 50 °C was studied. The barrier layer thickness before and after dissolution was determined using a re-anodizing
technique. Re-anodizing was conducted in 0.5 mol dm−3 H3BO3/0.05 mol dm−3 Na2B4O7 solution. We found that the change in the porous oxide growth mechanism was observed at the anodizing voltage of 30 V. Taking
into account this result chemical dissolution behaviour of the barrier layer of porous films formed at 20 V and 36 V and also
the influence of annealing of oxide films at 200 °C were studied. We showed the interplay between the dissolution rates and
charge distribution across the barrier layer. We conclude that the outer and middle layers have negative space charges and
the inner layer has positive space charges. 相似文献
5.
Yuri Pleskov Alik Tameev Valentin Varnin Irina Teremetskaya 《Journal of Solid State Electrochemistry》1998,3(1):25-30
The drift mobility of nonequilibrium holes injected in undoped polycrystalline diamond films was determined, by a transit-time
technique, as ca. 10−3 cm2/(V s). This hole mobility is three orders of magnitude lower than the “equilibrium” mobility in boron-doped diamond films
[0.1–1 cm2/(V s)], determined from the films' dc conductivity. This difference is explained by the effect of a nonequilibrium charge
carrier trapping during the carrier transport in polycrystalline diamond.
Received: 3 December 1997 / Accepted: 9 April 1998 相似文献
6.
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
7.
A new modified electrode was prepared by electrodeposition of caffeic acid (CFA) at the surface of an activated glassy carbon
electrode. Cyclic voltammetry was used to investigate the redox properties of this electrode at various solution pH values
and at various scan rates. The pH dependence of the electrode response was found to be 58.5 mV/pH, which is very close to
the expected Nernstian value. The electrode was also employed to study electrocatalytic oxidation of reduced nicotinamide
adenine dinucleotide (NADH), using cyclic voltammetry, chronoamperometry and rotating disk voltammetry as diagnostic techniques.
It was found that the modified electrode exhibits potent and persistent electrocatalytic properties toward NADH oxidation
in phosphate buffer solution (pH 7.0) with a diminution of the overpotential of about 450 mV compared to the process at an
unmodified electrode. The electrocatalytic current increases linearly with NADH concentration in the range tested from 0.05
to 1.0 mM. The apparent charge transfer rate constant and transfer coefficient for electron transfer between the electrode
surface and immobilized CFA were calculated as 11.2 s−1 and 0.43, respectively. The heterogeneous rate constant for oxidation of NADH at the CFA-modified electrode surface was also
determined and found to be about 3 × 103 M−1 s−1. Finally, the diffusion coefficient of NADH was calculated as 3.24 × 10−6 cm2 s−1 for the experimental conditions, using chronoamperometric results.
Received: 6 January 1999 / Accepted: 11 May 1999 相似文献
8.
Letao Wang Yan Zhang Yongling Du Daban Lu Yuzhen Zhang Chunming Wang 《Journal of Solid State Electrochemistry》2012,16(4):1323-1331
Simultaneous determination of catechol (CC) and hydroquinone (HQ) were investigated by voltammetry based on glassy carbon
electrode (GCE) modified by poly (diallyldimethylammonium chloride) (PDDA) functionalized graphene (PDDA-G). The modified
electrode showed excellent sensitivity and selectivity properties for the two dihydroxybenzene isomers. In 0.1 mol/L phosphate
buffer solution (PBS, pH 7.0), the oxidation peak potential difference between CC and HQ was 108 mV, and the peaks on the
PDDA-G/GCE were three times as high as the ones on graphene-modified glass carbon electrode. Under optimized conditions, the
PDDA-G/GCE showed wide linear behaviors in the range of 1 × 10−6−4 × 10−4 mol/L for CC and 1 × 10−6−5 × 10−4 mol/L for HQ, with the detection limits 2.0 × 10−7 mol/L for CC and 2.5 × 10−7 mol/L for HQ (S/N = 3) in mixture, respectively. Some kinetic parameters, such as the electron transfer number (n), charge transfer coefficient (α), and the apparent heterogeneous electron transfer rate constant (k
s), were calculated. The proposed method was applied to simultaneous determine CC and HQ in real water samples of Yellow River
with satisfactory results. 相似文献
9.
Akinbulu Isaac Adebayo Ozoemena Kenneth Iyke Nyokong Tebello 《Journal of Solid State Electrochemistry》2011,15(10):2239-2251
Molecular thin films of manganese (SAM-2), iron (SAM-3), and cobalt (SAM-4) phthalocyanine complexes, non-peripherally tetra-substituted with benzylmercapto, were formed on polycrystalline gold disc
electrode by self-assembly technique. Surface characteristics of the films were interrogated by cyclic voltammetry. Significant
passivation of voltammetry processes associated with bare gold surface (gold oxidation and underpotential deposition of copper)
confirmed formation of the films. Electrocatalytic property of the films was evidenced from better voltammetry responses (less
positive oxidation potential and better current signal) of the insecticide, carbofuran, on these films, relative to that on
bare gold electrode. In terms of less positive oxidation potential, the FePc derivative (3) gave the best response, while the best current signal was observed on SAM-2-modified gold electrode. The average heterogeneous rate constant, k, for the oxidation of carbofuran was 3.6 × 10−2 cm s−1 on the SAM film with the best current signal (SAM-2). 相似文献
10.
M. Chatelut S. Chah-Bouzziri O. Vittori A. Benayada 《Journal of Solid State Electrochemistry》2000,4(8):435-443
A lead electrode was studied in 6 and 12 M H3PO4. Oxidation of a freshly polished electrode occurred in the −0.5 to −0.3 V vs. SCE range, and led to PbHPO4 growth on the electrode surface. The dissolution of this layer by electrochemical reduction occurred between −0.5 and −0.7 V.
The influence of temperature (20 °C and 65 °C) was investigated and showed that the anodic and the cathodic peaks were increasing,
and more markedly for the 12 M H3PO4. The ratio Q
cathodic/Q
anodic (Q=electrical charge flowing through the electrode) was equal or close to the unity at 20 °C and decreased as the temperature
was increased. The influence of Cl−, Br− and I− ions was also evaluated. The addition of Cl− and Br− predominantly led to Pb5(PO4)3Cl and Pb5(PO4)3Br, respectively, while I− led to a mixture of PbI2 and PbHPO4.
Received: 18 July 1999 / Accepted: 2 November 1999 相似文献
11.
Graham A. Bowmaker Paul A. Kilmartin Graham A. Wright 《Journal of Solid State Electrochemistry》1999,3(3):163-171
Stable, yellow anodic films of parathiocyanogen (SCN)
x
were formed on a platinum electrode from 2.8 M KSCN in methanol at 45 °C at a constant current of 20–40 mA cm−2 for 15–30 min. Loosely bound orange crystals of a more amorphous character were removed by rinsing to leave an adherent yellow
film with sharp Raman bands under 647.1 nm laser excitation at 627 cm−1 (vCS), 1152 cm−1 and 1236–1261 cm−1 (vNN and vCN). The lack of electroactivity and short-lived photocurrents pointed to an insulating film at potentials up to 1.0 V (SHE).
At more positive potentials, longer-lasting photocurrents were obtained, consistent with breakdown of the insulating film.
XPS scans confirmed N:C:S ratios close to 1:1:1, with a deficiency of S of some 10% due to S lost as sulfate at the film surface.
Oxidation of SeCN− in neutral aqueous solution led to the formation of a less-stable orange paraselenocyanogen film with a Raman band at 1256–1267 cm−1, which decomposed within a day to grey selenium.
Received: 12 December 1997 / Accepted: 23 March 1998 相似文献
12.
Gongjun Yang Xilong Qu Ming Shen Chengyin Wang Qishu Qu Xiaoya Hu 《Mikrochimica acta》2008,160(1-2):275-281
Poly(phenol red) (denoted as PPR) films were electrochemically synthesized on the surface of a glassy carbon electrode (GCE)
by cyclic voltammetry to obtain a chemically modified electrode (denoted as PPR-GCE). The growth mechanism of PPR films was
studied by attenuated total reflection spectroscopy. This PPR-GCE was used to develop a novel and reliable method for the
determination of trace Pb2+ by anodic stripping differential pulse voltammetry. At optimum conditions, the anodic peak exhibits a good linear concentration
dependence in the range from 5.0 × 10−9 to 5.0 × 10−7 mol L−1 (r = 0.9989). The detection limit is 2.0 × 10−9 mol L−1 (S/N = 3). The method was employed to determine trace levels of Pb2+ in industrial waste water samples.
Correspondence: Gongjun Yang, Ming Shen, College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002,
P.R. China 相似文献
13.
The electrode characteristics and selectivities of PVC-based thiocyanate selective polymeric membrane electrode (PME) incorporating
the newly synthesized zinc complex of 6,7:14,15-Bzo2-10,11-(4-methylbenzene)-[15]-6,8,12,14-tetraene-9,12-N2-1,5-O2 (I
1
) and zinc complex of 6,7:14,15-Bzo2-10,11-(4-methylbenzene)-[15]-6,14-diene-9,12-dimethylacrylate-9,12-N2-1,5-O2 (I
2
) are reported here. The best response was observed with the membrane having a composition of I2:PVC:o-NPOE:HTAB in the ratio of 6:33:59:2 (w/w; milligram). This electrode exhibited Nernstian slope for thiocyanate ions over working concentration range of 4.4 × 10−7 to 1.0 × 10−2 mol L−1 with detection limit of 2.2 × 10−7 mol L−1. The performance of this electrode was compared with coated graphite electrode (CGE), which showed better response characteristics
w.r.t Nernstian slope 59.0 ± 0.2 mV decade−1 activity, wide concentration range of 8.9 × 10−8 to 1.0 × 10−2 mol L−1 and detection limit of 6.7 × 10−8 mol L−1. The response time for CGE and PME was found to be 8 and 10 s, respectively. The proposed electrode (CGE) was successfully
applied to direct determination of thiocyanate in biological and environmental samples and also as indicator electrode in
potentiometric titration of SCN− ion. 相似文献
14.
The fabrication and electrochemical characteristics of a penicillamine (PCA) self-assembled monolayer modified gold electrode
were investigated. The electrode can enhance the electrochemical response of uric acid (UA), and the electrochemical reaction
of UA on the PCA electrode has been studied by cyclic voltammetry and differential pulse voltammetry. Some electrochemical
parameters, such as diffusion coefficient, standard rate constant, electron transfer coefficient and proton transfer number
have been determined for the electrochemical behavior on the PCA self-assembled monolayer electrode. The electrode reaction
of UA is an irreversible process, which is controlled by the diffusion of UA with two electrons and two protons transfer at
the PCA/Au electrode. In phosphate buffer (pH 5.0), the peak current is proportional to the concentration of UA in the range
of 6.0 × 10−5–7.0 × 10−4 mol L−1 and 2.0 × 10−5–7.0 × 10−4 mol L−1 for the cyclic voltammetry and differential pulse voltammetry methods with the detection limits of 5.0 × 10−6 and 3.0 × 10−6 mol L−1, respectively. The method can be applied to determine UA concentration in real samples. 相似文献
15.
Lei Zhang 《Mikrochimica acta》2008,161(1-2):191-200
A covalently modified glassy carbon electrode with cysteine has been fabricated via an electrochemical oxidation procedure
and was applied to induce the electrochemical differentiation between dopamine (DA) and ascorbic acid (AA). Based on the electrostatic
interactions between the negatively charged groups on the electrode surface and DA and AA, the modified electrode enhanced
the oxidation of DA, reducing the overpotential by 180 mV, and hindered the oxidation of AA, shifting the oxidation potential
positively by 170 mV. The peak current for DA at the modified electrode was greatly enhanced and that for AA was significantly
decreased, which allows the determination of DA in the presence of AA. The differential pulse peak current was linearly dependent
on DA concentration over the range of 5 × 10−6–2 × 10−4 mol L−1. The detection limit was 1.8 × 10−6 mol L−1. The selectivity and sensitivity for dopamine is due to charge discrimination and analyte accumulation. The modified electrode
has been applied to the determination of DA in the presence of AA.
Correspondence: L. Zhang, Department of Chemistry, College of Life and Environmental Science, Shanghai Normal University,
Guilin Rd 100, Shanghai 200234, P.R. China 相似文献
16.
Bolade O. Agboola Sibulelo L. Vilakazi Kenneth I. Ozoemena 《Journal of Solid State Electrochemistry》2009,13(9):1367-1379
Electrochemistry of water-soluble cobalt(II) tetrasulfophthalocyanine (CoTSPc) electrodeposited on glassy carbon nanotube
pre-modified with acid-functionalized multi-walled carbon nanotubes (MWCNT) is described. Both charge transfer resistances
toward [Fe(CN)6]3−/4− redox probe and electrocatalytic responses toward epinephrine (EP) detection follow the trend: bare GCE < GCE-MWCNT < GCE-CoTSPc < GCE-MWCNT-CoTSPc.
EP analysis was then carried out in details using GCE-MWCNT-CoTSPc. The catalytic rate constant value k
ch = 2.2 × 107 (mol cm−3)−1 s−1 was obtained from rotating disk electrode experiment. Interestingly, GCE-MWCNT-CoTSPc efficiently suppressed the detection
of ascorbic acid (the natural interference of neurotransmitters in physiological conditions) showing good sensitivity (0.132 ± 0.003 A
l mol−1), limit of detection (4.517 × 10−7 mol l−1), and quantification (15.056 × 10−7 mol l−1). In addition, GCE-MWCNT-CoTSPc was conveniently used to determine EP in epinephrine hydrochloric acid injection with recovery
of 101.1 ± 2.2%. 相似文献
17.
Liang Wang Jun Yue Bai Peng Fei Huang Hong Jing Wang Xiao Wei Wu Yu Qing Zhao 《Mikrochimica acta》2007,158(1-2):73-78
The electrochemical behaviors of uric acid (UA) at the penicillamine (Pen) self-assembled monolayers modified gold electrode
(Pen/Au) have been studied. The Pen/Au electrode is demonstrated to promote the electrochemical response of UA by cyclic voltammetry
(CV). The diffusion coefficient D of UA is 6.97 × 10−6 cm2 s−1. In differential pulse voltammetric (DPV) measurements, the Pen/Au electrode can separate the UA and ascorbic acid (AA) oxidation
potentials by about 120 mV and can be used for the selective determination of UA in the presence of AA. The detection limit
was 1 × 10−6 mol L−1. The modified electrode shows excellent sensitivity, good selectivity and antifouling properties. 相似文献
18.
Jun Yue Bai Liang Wang Hong Jing Wang Peng Fei Huang Yu Qing Zhao Sheng Di Fan 《Mikrochimica acta》2006,156(3-4):321-326
The electrochemical behavior of epinephrine (EP) at a mercaptoacetic acid (MAA) self-assembled monolayer modified gold electrode
was studied. The MAA/Au electrode is demonstrated to promote the electrochemical response of epinephrine by cyclic voltammetry.
The possible reaction mechanism is also discussed. The diffusion coefficient D of EP is 6.85 × 10−6 cm2 s−1. In 0.1 mol L−1 phosphate buffer (pH 7.20), a sensitive oxidation peak was observed at 0.177 V, and the peak current is proportional to the
concentration of EP in the range of 1.0 × 10−5–2.0 × 10−4 mol L−1 and 1.0 × 10−7–1.0 × 10−6 mol L−1. The detection limit is 5 × 10−8 mol L−1. The modified electrode is highly stable and can be applied to the determination of EP in practical injection samples. The
method is simple, quick, sensitive and accurate. 相似文献
19.
Juliana Canto Duarte Rita de Cássia Silva Luz Flavio Santos Damos Adriano Bof de Oliveira Lauro Tatsuo Kubota 《Journal of Solid State Electrochemistry》2007,11(5):631-638
The electrocatalytical oxidation of hydrazine at low potential using tetracyanoquinodimethanide adsorbed on silica modified
with titanium oxide was investigated by cyclic voltammetry and amperometry. The modified electrode was prepared modifying
a carbon paste electrode employing lithium tetracyanoquinodimethanide adsorbed onto silica gel modified with titanium oxide.
This electrode showed an excellent catalytic activity and stability for hydrazine oxidation. With this modified electrode,
the oxidation potential of hydrazine was shifted toward less positive value, presenting a peak current much higher than those
observed on a bare GC electrode. The linear response range, sensitivity and detection limit were, respectively, 2 up to 100 μmol
l−1, 0.36 μA l μmol−1, and 0.60 μmol l−1. The repeatability of the modified electrode evaluated in term of relative standard deviation was 4.2% for 10 measurements
of 100 μmol l−1 hydrazine solution. The number of electrons involved in hydrazine oxidation (4), the heterogenous electron transfer rate
constant (1.08 × 103 mol−1 l s−1), and diffusion coefficient (5.9 × 10−6 cm2 s−1) were evaluated with a rotating disk electrode. 相似文献
20.
Carboxyl group-functionalized single-walled carbon nanotubes (SWNTs) and 2,6-pyridinedicarboxylic acid (PDC) were electropolymerized
by cyclic voltammetry on a glassy-carbon electrode (GCE) surface to form composite films (SWNTs/PDC). Zirconia was then electrodeposited
on the SWNTs/PDC/GCE from an aqueous electrolyte containing ZrOCl2 and KCl by cycling the potential between −1.1 V and +0.7 V at a scan rate of 20 mV s−1. DNA probes with a phosphate group at the 5′ end were easily immobilized on the zirconia thin films, because of the strong
affinity between zirconia and phosphate groups. The sensors were characterized by cyclic voltammetry (CV) and electrochemical
impedance spectroscopy (EIS). EIS was used for label-free detection of the target DNA by measuring the increase of the electron
transfer resistance (R
et) of the electrode surface after the hybridization of the probe DNA with the target DNA. The PAT gene fragment and polymerase
chain reaction (PCR) amplification of the NOS gene from transgenically modified beans were satisfactorily detected by use
of this DNA electrochemical sensor. The dynamic range of detection of the sensor for the PAT gene fragment was from 1.0 × 10−11 to 1.0 × 10−6 mol L−1 and the detection limit was 1.38 × 10−12 mol L−1. 相似文献