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    Electrocatalytic oxidation of methane at nickel hydroxide modified nickel electrode in alkaline solution

    , Article Electrochemistry Communications ; Volume 5, Issue 2 , 2003 , Pages 184-188 ; 13882481 (ISSN) Jafarian, M ; Mahjani, M. G ; Heli, H ; Gobal, F ; Heydarpoor, M ; Sharif University of Technology
    Elsevier Inc  2003
    Abstract
    Nickel hydroxide modified nickel electrodes prepared by cycling the potential of a nickel electrode in alkaline solution exhibited electrocatalytic activity for the oxidation of methane in alkaline media. In the presence of methane the oxidation peak current of nickel hydroxide increases while that of the reverse process decreases. This is attributed to the mediation of nickel species, probably β-NiOOH phase, in the process of electrocatalysis. The mechanism of methane oxidation has also been discussed in terms of the formations of intermediates normally encountered in small organics electro-oxidation. It has also been suggested that in the further oxidation of the intermediates, ions in the... 

    Voltammetric determination of dopamine at the surface of TiO2 nanoparticles modified carbon paste electrode

    , Article International Journal of Electrochemical Science ; Volume 5, Issue 1 , 2010 , Pages 147-157 ; 14523981 (ISSN) Mazloum-Ardakani, M ; Rajabi, H ; Beitollahi, H ; Mirjalili, B.B.F ; Akbari, A ; Taghavinia, N ; Sharif University of Technology
    2010
    Abstract
    In the present paper, the use of a novel carbon paste electrode modified by N,N'(2,3-dihydroxybenzylidene)-1,4-phenylenediamine (DHBPD) and TiO2 nanoparticles prepared by a simple and rapid method for the determination of dopamine (DA) was described. In the first part of the work, cyclic voltammetry was used to investigate the redox properties of this modified electrode at various solution pH values and at various scan rates. A linear segment was found with slope value of about 48 mV/pH in the pH range 2.0 -12.0. The apparent charge transfer rate constant (ks) and transfer coefficient (α) for electron transfer between DHBPD and TiO2 nanoparticles-carbon paste electrode were calculated. In... 

    Electrochemical synthesis of polypyrrole in the presence of congo red; application to selective voltammetric determination of dopamine in the presence of ascorbic acid

    , Article Electroanalysis ; Volume 21, Issue 2 , 2009 , Pages 157-164 ; 10400397 (ISSN) Shahrokhian, S ; Zare Mehrjardi, H. R ; Sharif University of Technology
    2009
    Abstract
    The electrosynthesis of polypyrrole (PPy) film has been achieved on glassy carbon electrode (GCE) in aqueous medium of Congo red (CR) by means of cyclic voltammetry (CV). The modified electrode exhibits high electrocatalytic activity toward dopamine (DA) oxidation, with drastic enhancement of the reversibility and peak currents. This modified electrode, due to electrostatic interactions, is capable to mask the response of ascorbic acid (AA) completely and provide an effective method for the detection of minor amounts of dopamine in the presence of high concentrations of AA. The electrochemical response of the film modified electrode is strongly dependent to the switching potential applied in... 

    Differential pulse voltammetric determination of propylthiouracil and methylthiouracil using their catalytic effects on the electrochemical oxidation of catechol

    , Article International Journal of Electrochemical Science ; Volume 2, Issue 2 , 2007 , Pages 158-168 ; 14523981 (ISSN) Shahrokhian, S ; Saberi, R. S ; Sharif University of Technology
    2007
    Abstract
    The electrochemical behavior of catechol in the presence of propylthiouracil (PTU) and methylthiouracil (MTU) at a glassy carbon electrode is thoroughly investigated. The cyclic voltammetric studies of the systems are performed in different pHs and sweep rates. The results of the voltammetric foundations show an electrocatalytic oxidation of catechol in the presence of PTU and MTU, leading to a remarkable increase in the anodic peak current of catechol together with the contemporaneous disappearance of the corresponding cathodic wave. The presented mechanism shows the nucleophilic addition/reduction of the electro-generated o-quinone by the PTU or MTU, which produced chemically reduced... 

    Electrocatalytic oxidation of penicillamine at a carbon paste electrode modified with cobalt salophen

    , Article Journal of Electroanalytical Chemistry ; Volume 565, Issue 1 , 2004 , Pages 95-101 ; 15726657 (ISSN) Shahrokhian, S ; Souri, A ; Khajehsharifi, H ; Sharif University of Technology
    Elsevier  2004
    Abstract
    Electrocatalytic oxidation of penicillamine (PA) at a carbon paste electrode chemically modified with cobalt salophen as a schiff base complex (CoSal) was thoroughly investigated. The results of cyclic voltammetry (CV) and polarization studies were used for the prediction of the mechanism of electrochemical oxidation of PA mediated with CoSal at the surface of a modified electrode. The performance of the modified electrode was compared with those of electrodes modified with cobalt phthalocyanine (CoPc). In comparison, CoSal appears to be considerably more effective as a catalyst for reduction of the overpotential of the anodic oxidation of PA, resulting in a very sharp anodic CV peak at... 

    Electrocatalytic oxidation of thioglycolic acid at carbon paste electrode modified with cobalt phthalocyanine: Application as a potentiometric sensor

    , Article Electrochimica Acta ; Volume 48, Issue 28 , 2003 , Pages 4143-4148 ; 00134686 (ISSN) Shahrokhian, S ; Yazdani, J ; Sharif University of Technology
    2003
    Abstract
    The voltammetric behavior of thioglycolic acid (TGA) was studied at a carbon paste electrode modified with cobalt phthalocyanine (CoPc). The CoPc-modified electrode shows high electrocatalytic activity toward oxidation of TGA, lowering substantially the overpotential of anodic reaction. Results of the cyclic voltammetry show that TGA undergoes a two-step oxidation (each step with one electron) resulting the dimer of thiol. Enhancement of the rate of electron transfer results in a near-Nernstian behavior of modified electrode to the concentration of TGA and makes it as a suitable potentiometric sensor for the detection of this compound. This electrode shows a near-Nernstian response in a wide... 

    Voltammetric determination of thiocytosine based on its electrocatalytic oxidation on the surface of carbon-paste electrode modified with cobalt schiff base complexes

    , Article Journal of Solid State Electrochemistry ; Volume 11, Issue 8 , 2007 , Pages 1133-1138 ; 14328488 (ISSN) Shahrokhian, S ; Amiri, M ; Sharif University of Technology
    2007
    Abstract
    The electrochemical oxidation of thiocytosine on the surface of carbon-paste electrode modified with Schiff base (salophen derivatives) complexes of cobalt is studied. The effect of the substituents in the structure of salophen on the catalytic property of the modified electrode is investigated by using cyclic and differential pulse voltammetry. Cobalt (II)-5-nitrosalophen, because of its electrophilic functional groups, leads to a considerable enhancement in the catalytic activity, sensitivity (peak current), and a marked increase in the anodic potential of the modified electrode. The differential pulse voltammetry is applied as a very sensitive method for the detection of thiocytosine. The... 

    Application of thionine-nafion supported on multi-walled carbon nanotube for preparation of a modified electrode in simultaneous voltammetric detection of dopamine and ascorbic acid

    , Article Electrochimica Acta ; Volume 52, Issue 22 , 2007 , Pages 6310-6317 ; 00134686 (ISSN) Shahrokhian, S ; Zare Mehrjardi, H. R ; Sharif University of Technology
    2007
    Abstract
    A modified carbon-paste electrode (CPE) is prepared by incorporating thionine-nafion supported on multi-walled carbon nanotube (MWCNT). The electrochemical behavior of dopamine (DA) and ascorbic acid (AA) on the surface of the modified electrode is investigated by cyclic voltammetry (CV). The results show that thionine effectively immobilized in the matrix of the paste by using an appropriate mixture of nafion/MWCNT under the ultrasonic condition. On the other hand, presence of nafion enhances the stability of the thionine supported by MWCNT in the composite electrode and improves the reproducibility of the surface of the modified electrode under renewing process by polishing. The results of... 

    Voltammetric studies of a cobalt(II)-4-methylsalophen modified carbon-paste electrode and its application for the simultaneous determination of cysteine and ascorbic acid

    , Article Electrochimica Acta ; Volume 50, Issue 1 , 2004 , Pages 77-84 ; 00134686 (ISSN) Shahrokhian, S ; Karimi, M ; Sharif University of Technology
    2004
    Abstract
    A carbon-paste electrode (CPE) chemically modified with the cobalt(II)-4-methylsalophen (CoMSal) as a Schiff base complex was used as a highly sensitive and fairly selective electrochemical sensor for simultaneous, determination of minor mounts of ascorbic acid (AA) and cysteine. This modified electrode shows very efficient electrocatalytic activity for anodic oxidation of both AA and cysteine via substantially decreasing of anodic overpotentials for both compounds. The. mechanism of electrochemical oxidation of both AA and cysteine using CoMSal-modified electrode was thoroughly investigated by cyclic voltammetry and polarization studies. Results of cyclic voltammetry (CV) and differential... 

    Kinetics and electrocatalytic behavior of nanocrystalline CoNiFe alloy in hydrogen evolution reaction

    , Article International Journal of Hydrogen Energy ; Volume 32, Issue 12 , 2007 , Pages 1686-1693 ; 03603199 (ISSN) Jafarian, M ; Azizi, O ; Gobal, F ; Mahjani, M. G ; Sharif University of Technology
    2007
    Abstract
    Electrocatalytic activity of electrodeposited nanocrystalline CoNiFe alloy in hydrogen evolution reaction (HER) was studied in 1 M NaOH solution. The steady-state polarization measurement and electrochemical impedance spectroscopy were used to determine the Tafel slope, the exchange current density and the activation energy. The simulation of the data obtained from these two methods, using a nonlinear fitting procedure, allowed us to determine the surface coverage and the rate constants associated with the mentioned reaction. The ac-impedance spectra measured at various overpotentials in the HER region exhibited three semicircles in the complex plane plots. The high-frequency semicircle was... 

    Cobalt salophen-modified carbon-paste electrode incorporating a cationic surfactant for simultaneous voltammetric detection of ascorbic acid and dopamine

    , Article Sensors and Actuators, B: Chemical ; Volume 121, Issue 2 , 2007 , Pages 530-537 ; 09254005 (ISSN) Shahrokhian, S ; Zare Mehrjardi, H. R ; Sharif University of Technology
    2007
    Abstract
    A carbon-paste electrode (CPE) is modified by incorporating cobalt-5-nitrosalophen (CoNSal) and tetraoctylammonium bromide (TOAB). The mechanism of electrocatalytic oxidation of dopamine (DA) and ascorbic acid (AA) at the surface of the CoNSal-modified CPE containing various percents of TOAB is thoroughly investigated by cyclic and differential pulse voltammetry. In solutions of pH 5.0, in which all studies are performed, DA exists as the positively charged species whereas AA is mainly as the neutral form. Therefore, the favorable ionic interaction (electrostatic repulsion) between the cationic form of DA and the cationic surfactant (TOA+) caused increasing the overvoltage for DA and... 

    Novel nanostructure electrochemical sensor for electrocatalytic determination of norepinephrine in the presence of high concentrations of acetaminophene and folic acid

    , Article Applied Catalysis A: General ; Volume 378, Issue 2 , 2010 , Pages 195-201 ; 0926860X (ISSN) Mazloum Ardakani, M ; Beitollahi, H ; Sheikh Mohseni, M. A ; Naeimi, H ; Taghavinia, N ; Sharif University of Technology
    2010
    Abstract
    In the present paper, the use of a carbon paste electrode modified by 2,2′-[1,2 buthanediylbis (nitriloethylidyne)]-bis-hydroquinone (BH) and TiO2 nanoparticles prepared by a simple and rapid method was described. The modified electrode showed an excellent character for electrocatalytic oxidization of norepinephrine (NE), acetaminophene (AC) and folic acid (FA). Using differential pulse voltammetry (DPV), a highly selective and simultaneous determination of NE, AC and FA has been explored at the modified electrode. Differential pulse voltammetry (DPV) peak currents of NE, AC and FA increased linearly with their concentration at the ranges of 4.0-1100.0 μM, 12.5-500.0 μM and 200.0-3200.0 μM,... 

    Nickel-based nanosheets array as a binder free and highly efficient catalyst for electrochemical hydrogen evolution reaction

    , Article International Journal of Hydrogen Energy ; Volume 47, Issue 82 , 2022 , Pages 34887-34897 ; 03603199 (ISSN) Faraji, H ; Hemmati, K ; Mirabbaszadeh, K ; Sharif University of Technology
    Elsevier Ltd  2022
    Abstract
    Hydrogen technology through water electrolyzer systems has attracted a great attention to overcome the energy crisis. So, rationally designed non-noble metal based-electrocatalysts with high activity and durability can lead to high performance water electrolyzer systems and high purity hydrogen generation. Herein, a facile two-step method: hydrothermal and electrodeposition, respectively, are developed to decorate highly porous three-dimensional binder-free structure NiFeO/NiO nanosheets array on Ni foam (NiFeO/NiO/NF) with robust adhesion as a high-performance electrode for Hydrogen Evolution Reaction (HER). The electrodeposition process applied after the initial hydrothermal process... 

    Electrochemical Behaviors of RuO2-TiO2 Mixed Metal Oxide Coated on Titanium Anodes in Chlor-Alkali Electrolysis

    , M.Sc. Thesis Sharif University of Technology Paryani, Kasra (Author) ; Ghorbani, Mohammad (Supervisor)
    Abstract
    Titanium anodes activated by noble metal oxides under the trade name of dimensionally stable anodes (DSAs) are widely used in the electrolytic industry, particularly in chlor – alkali electrolysis. Over 20 years of use, the fundamental aspects of their long – lasting performance are not fully understand and the corrosion mechanisms are still the subject of many investigations. RuO2 – TiO2 coatings on titanium substrate, due to proper electrochemical characteristics and good corrosion resistance, is most applicable as an anode in chlor – alkali systems. In the present investigation, the first layer of Pt – Ir coating is applied via electrodeposition method on the pretreated titanium substrate... 

    Electro-oxidation of alcohols on nickel dispersed in poly-o-aminophenol modified graphite electrode

    , Article Journal of Electroanalytical Chemistry ; Volume 652, Issue 1-2 , 2011 , Pages 8-12 ; 15726657 (ISSN) Jafarian, M ; Babaee, M ; Gobal, F ; Mahjani, M. G ; Sharif University of Technology
    2011
    Abstract
    Electro-oxidation of alcohols (methanol, ethanol, 1-propanol and 2-propanol) on nickel dispersed into a thick layer of poly-o-aminophenol on graphite electrode (GE/POAP-SDS/Ni) was investigated. Ni-doping into the polymeric film was achieved chemically followed by enrichment of Ni(III) through cycling the potential. The electro-oxidation of alcohols on GE/POAP-SDS/Ni were found to be dominated by direct electro-oxidation with some contribution from Ni(II)/Ni(III) couple. Rate constants for the electro-oxidation of methanol, ethanol, 1-propanol and 2-propanol as derived by chronoamperometry were 1.65 × 105, 1.31 × 105, 2.53 × 104 and 1.40 × 104 cm3 mol-1 s-1, respectively. Impedance... 

    Efficient electrocatalytic oxidation of water and glucose on dendritic-shaped multicomponent transition metals/spongy graphene composites

    , Article Electrochimica Acta ; Volume 386 , 2021 ; 00134686 (ISSN) Nourmohammadi Khiarak, B ; Mohammadi, R ; Mojaddami, M ; Rahmati, R ; Hemmati, A ; Simchi, A ; Sharif University of Technology
    Elsevier Ltd  2021
    Abstract
    To improve the efficiency of electrochemical processes for environmental remediation, we present a new type of hybrid nanomaterials based on leaf-like copper-based quaternary transition metals and spongy monolayer graphene. To demonstrate the functionality of the hybrid electrocatalyst, fast and competent electrooxidation of water and glucose is shown. The mechanism of improved catalysis is ascribed to the synergetic catalytic effect of quaternary Cu-Ni-Fe-Co alloy with dendritic morphology along with the highly conductive and spongy structure of the graphene monolayer. It is shown that water oxidation can be performed at a low overpotential of 315 mV to reach a current denisty of 100 mA... 

    Carbon-paste electrode modified with cobalt-5-nitrolsalophen as a sensitive voltammetric sensor for detection of captopril

    , Article Sensors and Actuators, B: Chemical ; Volume 109, Issue 2 , 2005 , Pages 278-284 ; 09254005 (ISSN) Shahrokhian, S ; Karimi, M ; Khajehsharifi, H ; Sharif University of Technology
    2005
    Abstract
    The electrochemical behavior of captopril at the surface of a carbon-paste electrode (CPE) modified with cobalt-5-nitrolsalophen (CoNSal) is described. The prepared electrode shows an excellent electrocatalytic activity toward the oxidation of captopril, which is leading to marked lowering in the anodic overpotential and considerable improvement of sensitivity (anodic current). Whereas at the surface of unmodified electrode an electrochemical activity for captopril cannot be observed, a very sharp anodic wave with an anodic peak potential about 650 mV (versus Ag/AgCl) is obtained using the prepared modified electrode. This catalytic wave is assigned to mediating of Co(III)/Co(II) redox... 

    Urchin-like hierarchical ruthenium cobalt oxide nanosheets on Ti3C2T: XMXene as a binder-free bifunctional electrode for overall water splitting and supercapacitors

    , Article Nanoscale ; Volume 14, Issue 4 , 2022 , Pages 1347-1362 ; 20403364 (ISSN) Asen, P ; Esfandiar, A ; Mehdipour, H ; Sharif University of Technology
    Royal Society of Chemistry  2022
    Abstract
    Synthesizing efficient electrode materials for water splitting and supercapacitors is essential for developing clean electrochemical energy conversion/storage devices. In the present work, we report the construction of a ruthenium cobalt oxide (RuCo2O4)/Ti3C2Tx MXene hybrid by electrophoretic deposition of Ti3C2Tx MXene on nickel foam (NF) followed by RuCo2O4 nanostructure growth through an electrodeposition process. Owing to the strong interactions between RuCo2O4 and Ti3C2Tx sheets, which are verified by density functional theory (DFT)-based simulations, RuCo2O4/Ti3C2Tx MXene@NF can serve as a bifunctional electrode for both water splitting and supercapacitor applications. This electrode... 

    Kinetic studies of glucose electrocatalytic oxidation on GC/Ni electrode

    , Article International Journal of Chemical Kinetics ; Volume 44, Issue 11 , 2012 , Pages 712-721 ; 05388066 (ISSN) Danaee, I ; Jafarian, M ; Forouzandeh, F ; Gobal, F ; Sharif University of Technology
    2012
    Abstract
    Nickel-modified glassy carbon electrode (GC/Ni) prepared by galvanostatic deposition was used for the electrocatalytic oxidation of glucose in alkaline solutions where different electrochemical methods were employed. In cyclic voltammetry studies, in the presence of glucose an increase in the peak current of the oxidation of nickel hydroxide is followed by a decrease in the corresponding cathodic current. This suggests that the oxidation of glucose is being catalyzed through mediated electron transfer across the nickel hydroxide layer comprising nickel ions of various valence states. Under the chronoamperometric regime, the reaction followed a Cottrellian behavior and the diffusion... 

    A comparative investigation of the electrocatalytic oxidation of methanol on poly-NiTCPP and poly-TCPP/Ni modified glassy carbon electrodes

    , Article Journal of Electroanalytical Chemistry ; Volume 663, Issue 1 , December , 2011 , Pages 14-23 ; 15726657 (ISSN) Jafarian, M ; Haghighatbin, M. A ; Gobal, F ; Mahjani, M. G ; Rayati, S ; Sharif University of Technology
    2011
    Abstract
    Electro-oxidation of methanol in alkaline solution at a glassy carbon electrode electrochemically modified by a conductive polymeric meso-tetra(4-carboxyphenyl)porphyrinato nickel(II), abbreviated as poly-NiTCPP and also meso-tetra(4-carboxyphenyl)porphyrin with incorporated nickel(II) cations, abbreviated as, poly-TCPP/Ni, were investigated and compared. Both films were prepared by oxidative electro-polymerization of complexes by repetitive cyclic voltammetry (RCV) in 0.1 M NaOH aqueous solution. The electrochemical properties and behaviors and also kinetic values of both films have been characterized and compared using cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical...