Loading...
Search for:
cyclic-voltammetry
0.011 seconds
Total 172 records
A low cost and highly active non-noble alloy electrocatalyst for hydrazine oxidation based on nickel ternary alloy at the surface of graphite electrode
, Article Journal of Electroanalytical Chemistry ; Volume 763 , 2016 , Pages 134-140 ; 15726657 (ISSN) ; Rostami, T ; Mahjani, M. G ; Gobal, F ; Sharif University of Technology
Elsevier B.V
2016
Abstract
The electrocatalytic oxidation of hydrazine was studied over Ni, Cu, Co and Ni-based ternary alloy on graphite electrodes in alkaline solution. The catalysts were prepared by cycling the graphite electrode in solutions containing Ni, Cu and Co ions at cathodic potentials. The synergistic effects and the catalytic activity of the modified electrodes were investigated by cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS). It was found that, in the presence of hydrazine, the modified Ni-based ternary alloy electrode (G/NiCuCo) exhibited a good catalytic activity for the oxidation of hydrazine at a reduced overpotential and it has a significant high...
Design and fabrication of an electrochemical aptasensor using Au nanoparticles/carbon nanoparticles/cellulose nanofibers nanocomposite for rapid and sensitive detection of Staphylococcus aureus
, Article Bioelectrochemistry ; Volume 123 , 2018 , Pages 70-76 ; 15675394 (ISSN) ; Shahrokhian, S ; Sharif University of Technology
Elsevier B.V
2018
Abstract
Since that pathogenic bacteria are major threats to human health, this paper describes the fabrication of an effective and durable sensing platform based on gold nanoparticles/carbon nanoparticles/cellulose nanofibers nanocomposite (AuNPs/CNPs/CNFs) at the surface of glassy carbon electrode for sensitive and selective detection of Staphylococcus aureus (S. aureus). The AuNPs/CNPs/CNFs nanocomposite with the high surface area, excellent conductivity, and good biocompatibility was used for self-assembled of the thiolated specific S. aureus aptamer as a sensing element. The surface morphology of AuNPs/CNPs/CNFs nanocomposite was characterized with field emission scanning electron microscopy...
Ultrasensitive detection of cancer biomarkers using conducting polymer/electrochemically reduced graphene oxide-based biosensor: Application toward BRCA1 sensing
, Article Sensors and Actuators, B: Chemical ; Volume 266 , 2018 , Pages 160-169 ; 09254005 (ISSN) ; Salimian, R ; Sharif University of Technology
Elsevier B.V
2018
Abstract
Breast Cancer (BRCA) is the most common threat in women worldwide. Increasing death rate of diagnosed cases is the main leading cause of designing specific genosensors for BRCA − related cancer detection. In the present study, an ultrasensitive label − free electrochemical DNA (E − DNA) sensor based on conducting polymer/reduced graphene − oxide platform has been developed for the detection of BRCA1 gene. An electrochemical method was applied as a simple and controllable technique for the electrochemical reduction of graphene oxide and also, electro − polymerization of pyrrole − 3 − carboxylic acid monomer. The results of the present work show that the polymer − coated reduced graphene −...
Nanoporous gold as a suitable substrate for preparation of a new sensitive electrochemical aptasensor for detection of salmonella typhimurium
, Article Sensors and Actuators, B: Chemical ; Volume 255 , 2018 , Pages 1536-1544 ; 09254005 (ISSN) ; Shahrokhian, S ; Nurmohammadi, F ; Sharif University of Technology
Elsevier B.V
2018
Abstract
Nowadays, achievement to easy, fast, reliable and cost-effective techniques and tools is one of the most important challenges in detection of microorganisms. Salmonella typhimurium is one of the most important pathogenic bacteria that affect the human health and environmental infections. In this work we report a new, stable, biocompatible and cost-effective platform for construction of an aptasensor based on nanoporous gold (NPG) for detection of S. typhimurium. Nanoporous gold is electrochemically synthesized using Au-Cu alloy at the surface of Au/GCE. Thiol functionalized aptamer is used for effective linking to the surface of NPG/Au/GCE via self-assemble monolayers (SAMs) formation....
Highly sensitive nonenzymetic glucose sensing platform based on MOF-derived NiCo LDH nanosheets/graphene nanoribbons composite
, Article Journal of Electroanalytical Chemistry ; Volume 808 , 2018 , Pages 114-123 ; 15726657 (ISSN) ; Shahrokhian, S ; Iraji Zad, A ; Sharif University of Technology
Elsevier B.V
2018
Abstract
Herein, a novel sensing platform based on NiCo layered double hydroxide (LDH) nanosheets/graphene nanoribbons (GNRs) modified glassy carbon electrode is presented for sensitive non-enzymetic determination of glucose. In the first step, nanoflower-like NiCo LDH nanosheets were grown on the surface of ZIF-67 dodecahedron nanocrystals which used as sacrificial template and were further characterized by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), X-ray powder diffraction (XRD) and FTIR. In the next step, in order to fabricate a mechanically stable modified electrode, the as-prepared nanosheets were mixed with...
An electrochemical sensing platform based on nitrogen-doped hollow carbon spheres for sensitive and selective isoprenaline detection
, Article Journal of Electroanalytical Chemistry ; Volume 847 , 2019 ; 15726657 (ISSN) ; Panahi, S ; Salimian, R ; Sharif University of Technology
Elsevier B.V
2019
Abstract
In this work, uniform and monodisperse hollow carbon spheres (HCSs) are synthesized through two different processes using polydopamine (PDA), as a carbon precursor, and silica core as a template, under the modified Stöber condition. The surface morphology of the synthesized structures is characterized by means of scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and Fourier-transform infrared spectroscopy (FT-IR). In the next step, the electrochemical behavior of isoprenaline (ISPN) is investigated by using glassy carbon electrode modified with a thin film of the synthesized hollow carbon spheres. The electrochemical characterization of the modified electrodes is...
ZnO nanoparticle/nanorod-based label-free electrochemical immunoassay for rapid detection of MMP-9 biomarker
, Article Biochemical Engineering Journal ; Volume 164 , 2020 ; Abdekhodaie, M. J ; Mousavi, S. A ; Taghipour, F ; Sharif University of Technology
Elsevier B.V
2020
Abstract
A label-free electrochemical biosensor was developed for the rapid detection of the matrix metalloproteinase 9 (MMP-9) biomarker on the basis of antibody immobilizing on the zinc oxide (ZnO) nanoparticle and ZnO nanorod electrodes. The charge transfer resistance (Rct) of the electrodes was used as the indicator for MMP-9 concentration, which was obtained through cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The ZnO nanorod-based biosensor exhibited linear behavior in the MMP-9 concentration range of 1–1000 ng/ml, which is a wider range than the available concentration ranges for most of the conventional methods. The biosensor sensitivity was 32.5 μA/(decade × cm2)...
Facile synthesis of N-doped hollow carbon nanospheres wrapped with transition metal oxides nanostructures as non-precious catalysts for the electro-oxidation of hydrazine
, Article Journal of Electroanalytical Chemistry ; Volume 873 , 2020 ; Rezaee, S ; Shahrokhian, S ; Sharif University of Technology
Elsevier B.V
2020
Abstract
In the present work, N-doped hollow carbon nanospheres (N-HCNSs) is prepared by direct carbonization of polyaniline-co-polypyrrole (PACP) hollow spheres without template needing. Two different NiO nanostructures (nanosheets and nanowires) are prepared by forming a shell around the N-HCNSs via simple hydrothermal/calcination processes (NiO-NSs@N-HCNSs and NiO-NWs@N-HCNSs). The morphology and structure of the nanostructures are characterized using field emission scanning electron microscopy (FE-SEM), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD). The prepared nanocomposites are used as catalysts for the electrocatalytic...
Bimetallic CoZn-MOFs easily derived from CoZn-LDHs, as a suitable platform in fabrication of a non-enzymatic electrochemical sensor for detecting glucose in human fluids
, Article Sensors and Actuators B: Chemical ; Volume 344 , 2021 ; 09254005 (ISSN) ; Shahrokhian, S ; Ezzati, M ; Sharif University of Technology
Elsevier B.V
2021
Abstract
In the present study, an in-situ, two-step, highly controllable, fast, green, and facile strategy for fabricating the bimetallic cobalt-zinc-based metal-organic frameworks (MOFs) is employed for designing a non-enzymatic glucose sensing platform. The structural characterization, as well as the phase investigation of materials in each step, are assessed by X-ray diffraction, energy-dispersive X-ray spectroscopy, elemental mapping, field emission scanning electron microscopy, and Fourier transform infrared spectroscopy. Furthermore, the electrocatalytic activity of the CoZn-BTC/GC fabricated electrode toward the electro-oxidation of glucose is examined by various electrochemical techniques,...
Microwave-assisted decoration of cotton fabrics with Nickel-Cobalt sulfide as a wearable glucose sensing platform
, Article Journal of Electroanalytical Chemistry ; Volume 890 , 2021 ; 15726657 (ISSN) ; Ezzati, M ; Shahrokhian, S ; Unalan, H. E ; Sharif University of Technology
Elsevier B.V
2021
Abstract
Flexibility and human-body compatibility have been emerged through the use of commercial fabrics (CFs) in designing wearable non-enzymatic glucose sensing platforms. In this work, electrodes fabricated through direct synthesis of ternary nickel–cobalt sulfide nanostructures (Ni-Co-S NSs) on the CFs (Ni-Co-S@CFs) using a fast and facile one-step microwave-assisted method for this purpose. Fabrication was followed by the structural and electrochemical characterization of the electrodes. The glucose-sensing ability of the prepared wearable electrodes was investigated via cyclic voltammetry (CV) and amperometry techniques in alkaline media. Two linear-responses in wide detection ranges of...
A new approach for simultaneously improved osseointegration and antibacterial activity by electrochemical deposition of graphene nanolayers over titania nanotubes
, Article Applied Surface Science ; Volume 580 , 2022 ; 01694332 (ISSN) ; Bagheri, R ; Vossoughi, M ; khafaji, M ; Asadian, E ; Ahmadi Seyedkhani, S ; Samadikuchaksaraei, A ; Sharif University of Technology
Elsevier B.V
2022
Abstract
Simultaneous enhancement of osseointegration and bacterial infection prohibition through surface modifications is a challenging but promising approach to achieve durable implantation. To that end, we present a multifunctional surface coating composed of graphene nanolayers and hierarchical well-aligned TiO2 nanotubes with a nanoporous top layer (cRTNT). FESEM studies reveal tunable increasing island morphologies of graphene nanolayers (G) on cRTNT by a cyclic voltammetry process. XPS analysis shows that the enhanced interface chemistry is due to TiO2-carbon bonding. The roughness of the sample containing a medium amount of graphene, cRTNT-75%GO, was calculated ∼289 nm, which was 543% higher...
Catechin mediated green synthesis of Au nanoparticles: Experimental and theoretical approaches to the determination HOMO-LUMO energy gap and reactivity indexes for the (+)-epicatechin (2S, 3S)
, Article Arabian Journal of Chemistry ; Volume 15, Issue 5 , 2022 ; 18785352 (ISSN) ; Khayatkashani, M ; Soltani, N ; Yousif, Q. A ; Salavati Niasari, M ; Sharif University of Technology
Elsevier B.V
2022
Abstract
This work suggests a green method for synthesizing Au nanoparticles (AuNPs) using the aqueous extract of Salix aegyptiaca extract. The mechanism of green synthesized AuNPs was examined by molecular electrostatic potential (MEP) calculations. AuNPs were characterized with different techniques such as Ultraviolet–visible spectroscopy (UV–vis), Fourier-transform infrared spectroscopy (FT-IR) spectroscopy, X-ray diffraction (XRD), and Transmission electron microscopy (TEM). Electrochemical investigation of modified glassy carbon electrode using AuNPs (AuNPs/GCE) shows that the electronic transmission rate between the modified electrode and [Fe (CN)6]3−/4− increased. Process of oxidation, energy...
Electrochemical preparation of a molecularly imprinted polypyrrole modified pencil graphite electrode for the determination of phenothiazine in model and real biological samples
, Article Talanta ; Volume 144 , November , 2015 , Pages 456-465 ; 00399140 (ISSN) ; Rouki, Z ; Nezhadali, M ; Sharif University of Technology
Elsevier
2015
Abstract
Abstract A sensitive electrochemical sensor for determination of phenothiazine (PTZ) was introduced based on molecularly imprinted polymer (MIP) film. A computational study was performed to evaluate the template-monomer geometry and interaction energy in the prepolymerization mixture. The electrode was prepared during electropolymerization of pyrrole (Py) on a pencil graphite electrode (PGE) by cyclic voltammetry (CV) technique. The quantitative measurements were performed using differential pulse voltammetry (DPV) in Britton-Robinson (BR) buffer solutions using 60% (v/v) acetonitrile-water (ACN/H2 O) binary solvent. The effect of important parameters like pH, monomer...
Electrochemical determination of l-dopa in the presence of ascorbic acid on the surface of the glassy carbon electrode modified by a bilayer of multi-walled carbon nanotube and poly-pyrrole doped with tiron
, Article Journal of Electroanalytical Chemistry ; Volume 636, Issue 1-2 , 2009 , Pages 40-46 ; 15726657 (ISSN) ; Asadian, E ; Sharif University of Technology
Elsevier
2009
Abstract
There are high attractions in the development of conducting polymer (CP) coatings to improve the electrochemical properties and biocompatibility of electrodes in the area of biosensors. A new type of the modified electrodes is prepared in a layer-by-layer process by using multi-walled carbon nanotube (MWCNT) and poly-pyrrole. In this procedure, the glassy carbon electrode is casted by a drop suspension of MWCNT, which leads to form a thin film of nanotube on its surface. In the second step, electrochemical polymerization of pyrrole in the presence of tiron (used as doping anion) is performed on the surface of the MWCNT pre-coated electrode. The modification procedure led to fabrication of a...
Electrocatalytic oxidation and nanomolar determination of guanine at the surface of a molybdenum (VI) complex-TiO2 nanoparticle modified carbon paste electrode
, Article Journal of Electroanalytical Chemistry ; Volume 624, Issue 1-2 , 2008 , Pages 73-78 ; 15726657 (ISSN) ; Taleat, Z ; Beitollahi, H ; Salavati Niasari, M ; Mirjalili, B. B. F ; Taghavinia, N ; Sharif University of Technology
Elsevier
2008
Abstract
A modified carbon paste electrode was prepared by incorporating TiO2 nanoparticles with bis[bis(salicylidene-1,4-phenylenediamine)molybdenum(VI)]. A mixture of fine graphite powder with 4 wt% of TiO2 nanoparticles was applied for the preparation of the carbon paste (by dispersing in paraffin) and finally modified with a molybdenum (VI) complex. The electrocatalytic oxidation of guanine (G) was investigated on the surface of the molybdenum (VI) complex-TiO2 nanoparticle modified carbon paste electrode (MCTNMCPE) using cyclic voltammetry (CV), differential pulse voltammetry (DPV), chronoamperometry (CHA) and chronocoloumetry (CHC). Using the modified electrode, the kinetics of G...
The electrocatalytic examination of cephalosporins at carbon paste electrode modified with CoSalophen
, Article Talanta ; Volume 71, Issue 4 , 2007 , Pages 1669-1674 ; 00399140 (ISSN) ; Rouhollahi, A ; Shahrokhian, S ; Haghgoo, S ; Aghajani, S ; Sharif University of Technology
Elsevier
2007
Abstract
The electrocatalytic oxidation of cephalexin and cefazolin has been studied at a carbon paste electrode modified with cobalt salophen (CoSal) by cyclic voltammetry. The selectivity of the carbon paste modified with CoSal in detecting cephalexin and cefazolin was examined. To suggest the electrocatalytic mechanism for electro-oxidation of cefazolin, the electrochemical behavior of ceftriaxone was investigated which has a thiol group out of the beta lactam ring. The electrocatalytic oxidation of these antibiotics is shown to be irreversible at the CoSal modified electrode. Scan rate dependence of cefazolin, which is a sulfur-containing compound, has been examined. The results indicated that...
Methanol electrooxidation on a nickel electrode modified by nickel-dimethylglyoxime complex formed by electrochemical synthesis
, Article Journal of Electroanalytical Chemistry ; Volume 588, Issue 1 , 2006 , Pages 155-160 ; 15726657 (ISSN) ; Asgari, M ; Ghannadi Maragheh, M ; Shahrokhian, S ; Sharif University of Technology
Elsevier
2006
Abstract
Nickel-dimethylglyoxime complex (NiDMG) modified nickel electrode (Ni/NiDMG) showed a catalytic activity towards methanol oxidation in NaOH solution. The modified electrode prepared by the dimethylglyoxime anodic deposition on Ni electrode in the solution containing 0.20 mol L-1 NH4Cl + NH4OH (pH 9.50) and 1.0 × 10-4 mol L-1 dimethylglyoxime. The modified electrode conditioned by potential recycling in a potential range of 100-700 mV (vs. SCE) by cyclic voltammetry in alkaline medium (0.10 M NaOH). The results show that the NiODMG film on the electrode behaves as an efficient catalyst for the electrooxidation of methanol in alkaline medium via Ni(III) species formed on the electrode with the...
A study on mutual interaction between atomistic and macroscopic phenomena during electrochemical processes using FD-KMC model: Application to CV test in simple copper sulfate bath
, Article Journal of Electroanalytical Chemistry ; Volume 592, Issue 1 , 2006 , Pages 95-102 ; 15726657 (ISSN) ; Sharif University of Technology
Elsevier
2006
Abstract
A multiscale FD-KMC model has been developed to simulate the cyclic voltammetry test of a copper electrode in simple copper sulfate bath. In this coupled model, the FD code provides the cupric ion concentration on OHP for KMC code, while the KMC code provides the electrochemical properties of the copper electrode (surface activity and rate constants of redox reactions) as an input data for FD code. The changes in the electrode properties due to the atomistic phenomena (deposition dissolution and surface diffusion) have been studied for the present potentiodynamic system. The results showed that the CV process consists of some distinct stages, so that the electrode exhibits a specific...
An electrochemical study of Au-Ni alloy electrodeposition from cyanide-citrate electrolytes
, Article Journal of Electroanalytical Chemistry ; Volume 577, Issue 1 , 2005 , Pages 1-8 ; 15726657 (ISSN) ; Ghorbani, M ; Ahmadi, M. R ; Sharif University of Technology
Elsevier
2005
Abstract
Cyclic voltammetry, j-t transients and transient time measurements have been used to characterize the Au-Ni alloy deposition and to obtain the nucleation and growth mechanism. The electrodeposition of gold, nickel and gold-nickel alloys was studied in cyanide-citrate electrolytes. The analysis of the voltammograms and j-t transients clearly shows that deposition of the Au and hence, of Au-Ni alloys, is affected by adsorbed cyanide ligands mainly at low overpotentials and a direct reduction occurs at high overpotentials. In this case, the Au deposition is kinetically favored, while the Ni deposition is controlled by the cyanide-citrate adsorbed adlayer. In an alloy electrolyte, the Au and Ni...
Enhanced hardness and corrosion resistance of Zn/SiO2 films by electrodeposition
,
Article
Journal of the Electrochemical Society
;
Volume 162, Issue 9
,
2015
,
Pages D480-D485
;
00134651 (ISSN)
; Salehi, F
; Razavizadeh, O
;
Sharif University of Technology
Electrochemical Society Inc
2015
Abstract
The electrodeposition of Zn-SiO2 nanocomposites has been investigated with different electrolytes: triethanolamine as a dispersing agent, and cetyl trimethylammonium bromide and dodecyl dimethylamine oxide as ionic (cationic) and non-ionic surfactants. Appropriate electrophoretic potentials for each solution were obtained using cyclic voltammetry. The results show that the most stable SiO2 nanoparticles with zeta potential range of 25 to 41 mV, along with highest SiO2 mobility of 0.4 to 0.7 m2/V.s were dispersed by triethanolamine in ethanol and the resulting coating adhesion improved up to 5.87 MPa in the standard pull off test, with the enhanced hardness of...