共查询到20条相似文献,搜索用时 593 毫秒
1.
Junjie Fei Xiaoqin Wen Lanhua Yi Fang Ge Ying Zhang Meihua Huang Xiaoming Chen 《Journal of Applied Electrochemistry》2008,38(11):1527-1533
Platinum nanoparticles (Ptnano) were prepared and used in combination with single-wall carbon nanotube (SWNT) for fabricating electrochemical sensors with
remarkably improved sensitivity toward diethylstilbestrol (DES). The glassy carbon (GC) electrode modified with SWNT/Ptnano composite film exhibited excellent electrochemical behaviors toward the redox of DES. Compared with the bare GC electrode
and SWNTs film modified GC electrode, the redox peak currents at the SWNTs/Ptnano composite film modified GC electrode was enhanced greatly. The experimental parameters, which influence the peak current
of DES, were optimized. Under optimal conditions, a linear response of DES was obtained in the range from 1.0 × 10−7 to 2.0 × 10−5 mol L−1 (R = 0.997) and with a limit of detect (LOD) of 1.5 × 10−8 mol L−1. The proposed procedure was successfully applied to determine the active ingredient in the DES tablet with satisfactory results. 相似文献
2.
[PFeW11O39]4− (PFeW11) supported on the surface of 3-aminopropyl(triethoxy)silane modified silica gel was synthesized and used as a bulk modifier to fabricate a renewable three-dimensional chemically modified electrode. The electrochemical behavior of the modified electrode was investigated. Cyclic voltammetry studies showed that the PFeW11 on the electrode surface sustained the same electrochemical properties as that of the PFeW11 in solution. The preparation of chemically modified electrode is simple and quiet reproducible using inexpensive material. The modified electrode had high electrocatalytic activity toward H2O2 reduction and it was successfully applied as an electrochemical detector to monitor H2O2 in flow injection analysis (FIA). The electrocatalytic peak current was found to be linear with the H2O2 concentration in the range 10-200 μmol L−1 with a correlation coefficient of 0.998 and a detection limit (3σ) of 7.4 μmol L−1 H2O2. The electrode has the remarkable advantage of surface renewal owing to bulk modification, as well as simple preparation, good mechanical and chemical stability and reproducibility. 相似文献
3.
Simple and eco-friendly electro deposition method was employed for the fabrication of Au–Ag bimetallic nanoparticles modified
glassy carbon electrode. Nano Au–Ag film modified glassy carbon electrode surface morphology has been examined using atomic
force microscopy. Electrodeposited Au–Ag bimetallic nanoparticles were found in the average size range of 15–50 nm. The electrochemical
investigations of nano Au–Ag/1-butyl-3-methylimidazolium tetrafluoroborate-nafion film have been carried out using cyclic
voltammetry and electrochemical impedance spectroscopy. The nano Au–Ag/1-butyl-3-methylimidazolium tetrafluoroborate-nafion
film modified glassy carbon electrode holds the good electrochemical behavior and stability in pH 7.0 phosphate buffer solutions.
The nano Au–Ag/1-butyl-3-methylimidazolium tetrafluoroborate-nafion modified glassy carbon electrode was successfully employed
for the detection of H2O2 in the linear range of 1–250 μM in lab samples, and 1 × 10−3–2 × 10−2 M in real samples, respectively. 相似文献
4.
A new electrochemical sensor based on copper nanoparticles for detection of hydrogen peroxide has been developed. Copper nanoparticles/Rutin/Multiwall Carbon Nanotubes/Ionic liquid/Chitosan modified glassy carbon electrode (CuNPs/Rutin/MWCNTs/IL/Chit/GCE) prepared by consecutive coating of MWCNTs/IL/Chit nanocomposite and rutin on the GCE, followed by the electrodeposition of copper. Surface physical characteristics of modified electrode were studied by scanning electron microscopy (SEM). The electrochemical performance of the sensor for detection of H2O2 was investigated by cyclic voltammetry and chronoamperometry techniques. The modified electrode exhibits an enhanced electrocatalytic property, low working potential, high sensitivity, excellent selectivity, good stability, and fast amperometric sensing towards reduction of hydrogen peroxide. The response to H2O2 is linear in the range between 0.35 μM to 2500 μM, and the detection limit is 0.11 μM. 相似文献
5.
Mohammad Mehdi Foroughi Shohreh Jahani Zahra Aramesh-Boroujeni Meisam Rostaminasab Dolatabad Kiana Shahbazkhani 《Ceramics International》2021,47(14):19727-19736
In this experiment, an original three-dimensional (3D) cubic of europium (Eu) 3+/cuprous oxide (Cu2O) with clover-like face-centered nanostructures (Eu3+/Cu2O CLFNs) was successfully synthesized to determine nevirapine (C15H14N4O), using electrochemical methods. The surface morphology of the Ns was correspondingly identified through different techniques, including energy dispersive X-ray spectroscopy (EDX), X-ray powder diffraction (XRD), and scanning electron microscopy (SEM). In this sense, the synergistic influence of the Eu3+/Cu2O CLFNs enhanced the electrocatalytic capability of the electrode via a modified glassy carbon (GC) and raised the active site. Employing various approaches, the modified electrode was then analyzed through cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Moreover, kinetic parameters and electrochemical ones were estimated by means of voltammetric methods. For the determination of nevirapine applying the Eu3+/Cu2O CLFNs/GC electrode (GCE), differential pulse voltammetry (DPV) was further utilized. Under optimized conditions, the range of linear responses was between 0.01 and 750.0 μM with the limit of detection (LOD) of 3.6 nM, whereas the recommended sensor sensitivity was equal to 0.1244 μA/μM. The response time of approximately 3.5 min and the reproducibility (inter- and intra-electrode reproducibility of 2.26% and 1.51%, respectively) were subsequently achieved. It was concluded that sensors have been thus far exploited to determine nevirapine in real samples with favorable outcomes, indicating that electrocatalysis modifier can be assumed as one of appropriate catalysts. 相似文献
6.
Sedigheh Hashemnia Hedayatollah Ghourchian Ali Aakbar Moosavi-Movahedi Hassan Faridnouri 《Journal of Applied Electrochemistry》2009,39(1):7-14
Catalase (Ct) was modified using Woodward’s reagent K (WRK) as a specific modifier of carboxyl residues. The modified Ct was
immobilized on an oxidatively activated glassy carbon electrode surface to investigate its direct electrochemistry. Using
cyclic voltammetry an irreversible reduction peak was obtained at approximately −0.362 V vs. Ag/AgCl in buffer solution, pH
7, and at a scan rate of 0.1 V s−1. The electrochemical parameters, including charge-transfer coefficient (0.27), apparent heterogeneous electron transfer rate
constant (13.51 ± 0.42 s−1) and formal potential of the Ct film (−0.275 V) were determined. The prepared enzyme electrode exhibited a response to H2O2. 相似文献
7.
Weihua Guo Lin Xu Bingbing Xu Yanyan Yang Zhixia Sun Shuping Liu 《Journal of Applied Electrochemistry》2009,39(5):647-652
Keggin-type polyoxometalate (H4SiMo12O40) and carbon nanotubes (CNTs) coated by poly(allylamine hydrochloride) (PAH) were alternately deposited on glassy carbon (GC)
electrodes by an electrochemical growth method in acidic aqueous solution. The preparation of the film electrode was simple
and convenient. Thus-prepared multilayer films and the electrochemical behavior of the composite film modified electrode were
characterized by UV–vis spectroscopy and cyclic voltammetry. It was shown that the multilayer films are uniform and stable.
The resulting multilayer film modified electrode behaves as an electrochemical sensor because of its low overpotential for
the catalytic reduction of S2O8
2− and NO2
− in acidic aqueous solution. 相似文献
8.
The electrochemical behaviors of dioxygen (O2) were studied by using rotate ring-disk electrode (RRDE) and other electrochemical methods at bare glassy carbon electrode (GCE) and single-walled carbon nanotubes (SWNTs)-dihexadecyl hydrogen phosphate (DHP) film modified GCE. The results showed that the electrochemical reduction of dioxygen was considered to proceed by a two-step two-electron reduction pathway at both bare GCE and SWNTs-DHP film modified GCE in 0.1 mol/L air-saturated sodium hydroxide (NaOH). Maybe because each reaction rate for two cases was different the cyclic voltammograms measurements exhibited different behaviors. The detection of ring current confirmed the presence of middle product hydrogen peroxide (H2O2). Furthermore, larger current and more positive reduction potential indicated that SWNTs showed a catalytic effect towards the electrochemical reduction of dioxygen. 相似文献
9.
Copper pyro-, ortho-, and tetra-phosphate compounds (Cu2P2O7, Cu3P2O8, and Cu4P2O9) with the general composition, CuxP2O5+x (x = 2, 3, 4), were prepared through the conventional solid-state synthesis route, and their optical properties and visible-infrared light-induced photocatalytic activities were investigated for the first time. The copper phosphate compounds showed comparable particle sizes, and their primary optical bandgaps were estimated to lie in the range of 2.8-3.6 eV. Their photocatalytic activity was evaluated by the kinetics of decomposition of rhodamine B (RhB) solution under visible-light irradiation (>420 nm). Among the three kinds of copper phosphate, Cu4P2O9 exhibited the highest photocatalytic activity due to its smallest bandgap (of the three compounds considered) and appropriate band positions. More interestingly, the three copper phosphate compounds, particularly Cu3P2O8, show strong near-infrared (NIR) light absorption, thereby enabling the NIR-induced photocatalytic decomposition of RhB in the presence of hydrogen peroxide. Finally, a possible photo-Fenton photocatalytic reaction mechanism was also proposed based on the band structure/position. 相似文献
10.
Ivar Kruusenberg 《Carbon》2009,47(3):651-280
The pH-dependence of oxygen electroreduction has been investigated on multi-walled carbon nanotube (MWCNT) modified glassy carbon (GC) electrodes. Various surfactants were used in the electrode modification: dihexadecyl hydrogen phosphate, cetyltrimethylammonium bromide, sodium dodecyl sulfate and Triton X-100. Electrochemical experiments were carried out in 0.5 M H2SO4 solution, acetate buffer (pH 5), phosphate buffers (pH 6, 7 and 8), borate buffer (pH 10), 0.01 M KOH, 0.1 M KOH and in 1 M KOH solution, using the rotating disk electrode (RDE) method. The oxygen reduction behaviour of MWCNT-modified GC electrodes at different pHs was compared. The RDE results revealed that the half-wave potential (E1/2) of oxygen reduction was higher in solutions of high pH. At lower pHs (pH < 10) the value of E1/2 did not essentially depend on the solution pH. A comparison with previous studies on bare GC showed that the pH-dependence of the half-wave potential of oxygen reduction on MWCNT-modified GC electrodes follows a similar trend to that observed for bare GC. 相似文献
11.
Muniyandi Rajkumar Soundappan Thiagarajan Shen-Ming Chen 《Journal of Applied Electrochemistry》2011,41(6):663-668
Electrochemical deposition method was employed for the fabrication of rhodium–palladium (Rh–Pd) particles on the glassy carbon
electrode (GCE) and indium tin oxide (ITO) electrode surface. Surface morphological analysis of Rh–Pd film has been carried
out using scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. Here, the electrodeposited Rh–Pd particles
were found in the average size range of 30–200 nm. The electrochemical activities of the Rh–Pd film have been investigated
using cyclic voltammetry (CV) and electrochemical impedance spectroscopic (EIS) analysis. The Rh–Pd particles-modified GCE
successfully detects the hydrogen peroxide (H2O2) (in pH 7.0 phosphate buffer solution (PBS)) in the linear range in the lab (10–460 μM) and real samples (10–340 μM). The
Rh–Pd particles-modified GCE possesses the good sensitivity and selectivity for the detection of H2O2 in lab and real samples. 相似文献
12.
Graphene was synthesized by a chemical method to reduce graphite oxide and well characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (PXRD) and Fourier transform infrared (FTIR) spectra. Horseradish peroxidase (HRP) immobilized on a graphene film glassy carbon electrode was found to undergo direct electron transfer and exhibited a fast electron transfer rate constant of 4.63 s−1. The HRP-immobilized electrode was investigated by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The CV results showed that the modified electrode gave rise to well-defined peaks in phosphate buffer, corresponding to the electrochemical redox reaction between HRP–Fe(III) and HRP–Fe(II). The obtained electrode also displayed an electrocatalytic reduction behavior towards H2O2. The new H2O2 sensor shows a linear range of 0.33–14.0 μM (R2 = 0.9987) with a calculated detection limit of 0.11 μM (S/N = 3). Furthermore, the biosensor exhibits both good operational storage and storage stability. 相似文献
13.
Vu Thi Huong Toshinori Shimanouchi Do Phuc Quan Hiroshi Umakoshi Pham Hung Viet Ryoichi Kuboi 《Journal of Applied Electrochemistry》2009,39(10):2035-2042
The possible use of an electrode modified with electroactive conductive poly(3-methylthiophene) (PMeT)/Nafion as a chemical
sensor was investigated for the voltammetric analysis of Dopamine (DA). The electrochemical behavior of dopamine was examined
by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. By using a PMeT-modified glassy carbon (GC/PMeT)
electrode, DA and Ascorbic Acid (AA) signals could be separated but the AA at high concentrations still caused significant
interference by overlapping the DA peak. In comparison to the GC/PMeT electrode, the glassy carbon (GC/Nafion/PMeT) electrode
modified with hybrid film Nafion/PMeT was found to permit a superior separation by shifting the oxidation of AA peak toward
the less positive potential. The DPV curves for a mixture of DA and AA at an GC/Nafion/PMeT electrode in a 0.1 M H2SO4 solution showed peaks of DA and AA, at 0.45 and 0.21 V, respectively, indicating that the difference in the oxidation potential
was 240 mV. In the 0.1 M H2SO4 solution, the oxidation peak current on the differential pulse voltammograms for the GC/PMeT electrode increased linearly
with the concentration of DA in the range 1 × 10−6 to 1 × 10−3 M, and the oxidation peak current on the differential pulse voltammograms for the GC/Nafion/PMeT electrode in the range 5 × 10−7 to 2 × 10−4 M. The DA detection sensitivity of the GC/Nafion/PMeT electrode (26.7 μA μM−1 cm−2) was 22 times higher than that of the GC/PMeT electrode (1.21 μA μM−1 cm−2). 相似文献
14.
Abdollah Salimi Monierosadat Mahdioun Abdollah Noorbakhsh Amir Abdolmaleki Raoof Ghavami 《Electrochimica acta》2011,(9):908
A simple procedure was developed to prepare a glassy carbon (GC) electrode modified with single wall carbon nanotubes (SWCNTs) and phenazine derivative of Mn-complex. With immersing the GC/CNTs modified electrode into Mn-complex solution for a short period of time 20–100 s, a stable thin layer of the complex was immobilized onto electrode surface. Modified electrode showed a well defined redox couples at wide pH range (1–12). The surface coverages and heterogeneous electron transfer rate constants (ks) of immobilized Mn-complex were approximately 1.58 × 10−10 mole cm−2 and 48.84 s−1. The modified electrode showed excellent electrocatalytic activity toward H2O2 reduction. Detection limit, sensitivity, linear concentration range and kcat for H2O2 were, 0.2 μM and 692 nA μM−1 cm−2, 1 μM to 1.5 mM and 7.96(±0.2) × 103 M−1 s−1, respectively. Compared to other modified electrodes, this electrode has many advantageous such as remarkable catalytic activity, good reproducibility, simple preparation procedure and long term stability. 相似文献
15.
Bromine (Br)-adatom (Br(ads)) was in situ fabricated onto polycrystalline gold (Au (poly)) electrode in Br−-containing alkaline media. The surface coverage of Br(ads) (ΓBr) varied only in the submonolayer coverage within the investigated potential window under potentiodynamic condition because of the coadsorption of hydroxyl ion (OH−) in alkaline media. The in situ fabricated Br(ads)-submonolayer-coated Au (poly) electrode was successfully used for the electrochemical oxidation of hydrogen peroxide (H2O2). About five times higher oxidation current was achieved at the modified electrode as compared with the bare electrode. The enhancement of the electrode activity towards the electrochemical oxidation of H2O2 was explained based on the enhanced electrostatic attraction between the anionic HO2− molecules and Br(ads)-adlayer-induced positively polarized Au (poly) electrode surface. 相似文献
16.
Mahmoud Roushani Zeinab Abdi Ali Daneshfar Abdollah Salimi 《Journal of Applied Electrochemistry》2013,43(12):1175-1183
A simple and sensitive electrochemical sensor based on nickel oxide nanoparticles/riboflavin-modified glassy carbon (NiONPs/RF/GC) electrode was constructed and utilized to determine H2O2. By immersing the NiONPs/GC-modified electrode into riboflavin (RF) solution for a short period of time (5–300 s), a thin film of the proposed molecule was immobilized onto the electrode surface. The modified electrode showed stable and a well-defined redox couples at a wide pH range (2–10), with surface-confined characteristics. Experimental results revealed that RF was adsorbed on the surface of NiONPs, and in comparison with usual methods for the immobilization of RF, such as electropolymerization, the electrochemical reversibility and stability of this modified electrode has been improved. The surface coverage and heterogeneous electron transfer rate constants (k s) of RF immobilized on a NiO x –GC electrode were approximately 4.83 × 10?11 mol cm?2, 54 s?1, respectively. The sensor exhibits a powerful electrocatalytic activity for the reduction of H2O2. The detection limit, sensitivity and catalytic rate constant (k cat) of the modified electrode toward H2O2 were 85 nM, 24 nA μM?1 and 7.3 (±0.2) × 103 M?1 s?1, respectively, at linear concentration rang up to 3.0 mM. The reproducibility of the sensor was investigated in 10 μM H2O2 by amperometry, the value obtained being 2.5 % (n = 10). Furthermore, the fabricated H2O2 chemical sensor exhibited an excellent stability, remarkable catalytic activity and reproducibility. 相似文献
17.
《Carbon》2013
Hydrogen peroxide (H2O2) is a versatile oxidizing agent that is synthesized commercially by the reduction of oxygen in organic medium. Electrochemical technology employing a modified gas diffusion electrode (MGDE) offers a viable alternative for the industrial-scale synthesis of the oxidant. Addition of 1% (w/w) of tert-butyl-anthraquinone (TBAQ) to carbon black deposited in the form of a microporous layer onto the disk of a rotating ring-disk electrode produced an increase in the ring current, which is directly related to H2O2 formation, and presented an efficiency of H2O2 generation of 89.6% compared with 76.6% for carbon black alone. No significant changes were detected in the number of electrons transferred in the presence of the catalyst suggesting an electrochemical/chemical mechanism for H2O2 formation. Analogous improvements in the generation of H2O2 were obtained with MGDEs comprising TBAQ on carbon black. The highest concentrations of H2O2 (301 mg L−1) were produced at the fastest rate (5.9 mg L−1 min−1) with the lowest energy consumption (6.0 kWh kg−1) when a potential of −1.0 V vs SCE was applied to a MGDE containing 1.0% of TBAQ on carbon black. It is concluded that the application of MGDEs comprising TBAQ on carbon black support offers considerable advantages in the electrogeneration of H2O2. 相似文献
18.
The electrochemical behavior of glassy carbon (GC) electrodes coated with multi-walled carbon nanotube (MWCNT)/surfactant films was studied in an ionic liquid and a phosphate buffer solution (pH = 6.86), using cyclic voltammetry. The dispersion of MWCNTs in different media was investigated by scanning and transmission electron microscopy. Cast films of MWCNT/zwitterionic dodecyldimethylamine oxide on a GC electrode show a typical redox couple in phosphate buffer solution, which is better than that of MWCNT/anionic sodium dodecyl sulfate and cationic alkyltrimethylammonium bromide. However in the ionic liquid, 1-n-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]), the GC electrode modified by MWCNT/cationic surfactant films shows a well-defined irreversible reduction of MWCNTs. The cyclic voltammograms clearly show that the surfactant hydrophilic group plays an important role in the electrochemical behavior of the MWCNTs. The electrolytes also have an important effect. In an ionic liquid, the strong binding of the ionic liquid cations with the MWCNTs may change the structure of the modified films and lead to changes of electrochemical behavior. 相似文献
19.
A monolayer of Keggin-type heteropolyanion [SiNi(H2O)W11O39]6− was fabricated by electrodepositing [SiNi(H2O)W11O39]6− on cysteamine modified gold electrode. The monolayer of [SiNi(H2O)W11O39]6− modified gold electrode was characterized by atomic force microscopy (AFM) and electrochemical method. AFM results showed the [SiNi(H2O)W11O39]6− uniformly deposited on the electrode surface and formed a porous monolayer. Cyclic voltammetry exhibited one oxidation peak and two reduction peaks in 1.0 M H2SO4 in the potential range of −0.2 to 0.7 V. The constructed electrode could exist in a large pH (0-7.6) range and showed good catalytic activity towards the reduction of bromate anion (BrO3−) and nitrite (NO2−), and oxidation of ascorbic acid (AA) in acidic solution. The well catalytic active of the electrode was ascribed to the porous structure of the [SiNi(H2O)W11O39]6− monolayer. 相似文献
20.
This work demonstrates that iron-enriched natural zeolitic volcanic tuff (Paglisa deposit, Cluj county, Transilvania, Romania) resulting from a previous use as adsorbent in wastewater treatment can be recycled into effective electrode modifier applied to the electrocatalytic detection of hydrogen peroxide. After physico-chemical characterization of tuff samples using various techniques such as chemical analysis, X-ray diffraction, scanning electron microscopy, infrared spectroscopy, BET analysis and X-ray photoelectron spectroscopy, the electrochemical response of the iron-enriched zeolites was studied on the basis of solid carbon paste electrodes modified with these samples. The results indicate that iron centers in the zeolite are electroactive and that they act as electrocatalysts in the voltammetric and amperometric detection of H2O2. Best performance was achieved in phosphate buffer at pH 7, showing a sensitivity of 0.57 mA M−1 cm−2, a detection limit down to 60 μM, and a linear domain up to 100 mM H2O2. 相似文献