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    A comparative study of the electrooxidation of C1 to C3 aliphatic alcohols on Ni modified graphite electrode

    , Article Science China Chemistry ; Volume 55, Issue 9 , 2012 , Pages 1819-1824 ; 16747291 (ISSN) Jafarian, M ; Mirzapoor, A ; Danaee, I ; Shahnazi, S. A. A ; Gobal, F ; Sharif University of Technology
    Abstract
    Nickel modified graphite electrodes (G/Ni) prepared by galvanostatic deposition were examined for their redox process and electrocatalytic activities towards the oxidation of methanol, ethanol, 1-propanol and 2-propanol in alkaline solutions. The methods of cyclic voltammetry (CV), chronoamperometry (CA) and impedance spectroscopy (EIS) were employed. In CV studies, the electrochemical response, peak current varied in the order of MeOH > EtOH > 1-PrOH > 2-PrOH. Under the CA regime, a higher catalytic rate constant obtained for methanol oxidation was in agreement with CV measurements. Lower charge transfer resistance was obtained for low carbon alcohols oxidation and significantly higher... 

    AC impedance and cyclic voltammetry studies on PbS semiconducting film prepared by electrodeposition

    , Article Journal of Electroanalytical Chemistry ; Volume 661, Issue 1 , 2011 , Pages 265-269 ; 15726657 (ISSN) Aghassi, A ; Jafarian, M ; Danaee, I ; Gobal, F ; Mahjani, M. G ; Sharif University of Technology
    Abstract
    Semiconducting lead sulfide film was deposited on Stainless Steel (SS) electrode by cyclic voltammetry (CV) at room temperature. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry were used to investigate the electrochemical properties of PbS film in Na2SO4 solution. The voltammetric results showed that oxidative dissolution of PbS film occurred at about 0.21 V vs. Ag/AgCl and total film detachment from the surface occurs with increasing potential. It is concluded that the electrode surface was not passivated by sulfur produced from oxidative dissolution of PbS film. Also, cathodic reduction of the film continued to beyond the hydrogen evolution at -1.35 V vs. Ag/AgCl.... 

    Electrochemical oxidation of saccharose on copper (hydr)oxide-modified electrode in alkaline media

    , Article Cuihua Xuebao/Chinese Journal of Catalysis ; Volume 31, Issue 11 , 2010 , Pages 1351-1357 ; 02539837 (ISSN) Jafarian, M ; Rashvand Avei, M ; Danaee, I ; Gobal, F ; Mahjani, M. G ; Sharif University of Technology
    2010
    Abstract
    A stable copper (hydr)oxide-modified electrode was prepared in 0.5 mol/L NaOH solution by cyclic voltammetry in the range of -250 to 1000 mV. It can be used for electrochemical studies in the range of -250 to 1000 mV without interfering peaks because there is no oxidation of copper. During an anodic potential sweep, the electro-oxidation of saccharose on Cu occurred by the formation of CuIII and this reaction also occurred in the early stages of the reversed cycle until it is stopped by the negative potentials. A mechanism based on the electro-chemical generation of CuIII active sites and their subsequent consumption by saccharose was proposed, and the rate law and kinetic parameters were... 

    Electrocatalytic oxidation of glucose on Ni and NiCu alloy modified glassy carbon electrode

    , Article Journal of Solid State Electrochemistry ; Volume 13, Issue 8 , 2009 , Pages 1171-1179 ; 14328488 (ISSN) Jafarian, M ; Forouzandeh, F ; Danaee, I ; Gobal, F ; Mahjani, M. G ; Sharif University of Technology
    2009
    Abstract
    Nickel and nickel-copper alloy modified glassy carbon electrodes (GC/Ni and GC/NiCu) prepared by galvanostatic deposition were examined for their redox processes and electro-catalytic activities towards the oxidation of glucose in alkaline solutions. The methods of cyclic voltammetry (CV) and chronoamperometry (CA) were employed. The cyclic voltammogram of NiCu alloy demonstrates the formation of β/β crystallographic forms of the nickel oxyhydroxide under prolonged repetitive potential cycling in alkaline solution. It is also observed that the overpotential for O 2 evolution increases for NiCu alloy modified electrode. In CV studies, NiCu alloy modified electrode yields significantly higher... 

    Electrodeposition of Al, Mn, and Al-Mn alloy on aluminum electrodes from molten salt (AlCl3-NaCl-KCl)

    , Article Journal of Applied Electrochemistry ; Volume 39, Issue 8 , 2009 , Pages 1297-1303 ; 0021891X (ISSN) Jafarian, M ; Maleki, A ; Danaee, I ; Gobal, F ; Mahjani, M. G ; Sharif University of Technology
    2009
    Abstract
    Electrochemical deposition of aluminum and manganese from basic and acidic molten AlCl3-NaCl-KCl mixture on an aluminum electrode at 180 °C was studied by the methods of voltammetry, and potential and current transient. The deposition of aluminum was found to proceed via a nucleation/growth mechanism in basic melt, while the deposition of manganese was found to be diffusion controlled in basic melt. The diffusion coefficient of Mn2+ ions in basic melt, as derived by voltammetry was in agreement with the deductions of transient methods. Analysis of the chronoamperograms indicates that the deposition of manganese on Al was controlled by 3D diffusion controlled nucleation and growth. The... 

    Electrocrystallization of Pb and Pb assisted Al on aluminum electrode from molten salt (AlCl3-NaCl-KCl)

    , Article Journal of Alloys and Compounds ; Volume 478, Issue 1-2 , 2009 , Pages 83-88 ; 09258388 (ISSN) Jafarian, M ; Danaee, I ; Maleki, A ; Gobal, F ; Mahjani, M. G ; Sharif University of Technology
    2009
    Abstract
    Electrochemical deposition of aluminum and lead from basic molten AlCl3-NaCl-KCl mixture on an aluminum electrode at 180 °C was studied by the methods of voltammetry, potential and current transient and constant current deposition. The deposition of aluminum was found to proceed via a nucleation/growth mechanism, while the deposition of lead was found to be diffusion controlled. The diffusion coefficient calculated for Pb2+ ions in basic melt by voltammetry was in agreement with the deductions of transient method. The analysis of the chronoamperograms indicates that the deposition process of lead on Al substrates was controlled by 3D diffusion control, nucleation and growth. The processes... 

    Electrochemical studies of the pitting corrosion of tin in citric acid solution containing Cl-

    , Article Electrochimica Acta ; Volume 53, Issue 13 , 2008 , Pages 4528-4536 ; 00134686 (ISSN) Jafarian, M ; Gobal, F ; Danaee, I ; Biabani, R ; Mahjani, M. G ; Sharif University of Technology
    2008
    Abstract
    The electrochemical behavior of a tin electrode in citric acid solutions of different concentrations was studied by electrochemical techniques. The E/I curves showed that the anodic behavior of tin exhibits active/passive transition. Passivation is due to the formation of Sn(OH)4 and/or SnO2 film on the electrode surface. Addition of NaCl to citric acid solution, enhances the active dissolution of tin and tends to breakdown the passivity at a certain breakdown potential. Cyclic voltammetry and galvanostatic measurements allow the pitting potential (Epit) and the repassivation potential (Erp) to be determined. Potentiostatic measurements showed that the overall anodic processes can be... 

    Impedance spectroscopy study of aluminum electrocrystallization from basic molten salt (AlCl3-NaCl-KCl)

    , Article Electrochimica Acta ; Volume 52, Issue 17 , 2007 , Pages 5437-5443 ; 00134686 (ISSN) Jafarian, M ; Gobal, F ; Danaee, I ; Mahjani, M. G ; Sharif University of Technology
    2007
    Abstract
    Aluminum electrocrystallization is studied by means of electrochemical impedance spectroscopy (EIS). A model based on random birth and deterministic growth of monolayers is proposed, in which the edges are assumed to follow a propagation law. The high frequency impedance data show charge transfer reaction of AlCl4- reduction while the low frequency features signifies the growth mode of deposits. The inductive response observed in the course of polycrystalline deposition reflects the activation of electrode area while a capacitive loop appears in regular growth. Parameters of impedance model in this system can be calculated from the fitting of experimental data to the Faradaic impedance... 

    Electrodeposition of aluminum from molten AlCl3-NaCl-KCl mixture

    , Article Journal of Applied Electrochemistry ; Volume 36, Issue 10 , 2006 , Pages 1169-1173 ; 0021891X (ISSN) Jafarian, M ; Mahjani, M.G ; Gobal, F ; Danaee, I ; Sharif University of Technology
    2006
    Abstract
    Electrochemical deposition of aluminum from basic and acidic molten NaCl-KCl-AlCl3 mixture on a graphite electrode at 140 °C was studied by voltammetry, chronopotentiometry and constant current deposition. The deposition of aluminum was found to proceed via a nucleation/growth mechanism in basic melt, while it was found to be diffusion controlled in acidic melt. The diffusion coefficient calculated for Al2Cl- 7 ions in acidic melt by voltammetry was in agreement with the deductions of voltammetry. The morphology of the aluminum deposits was examined using a metallographic microscope and by SEM. It was shown that, depending on the current density (c.d.) and AlCl3 concentration (acidic or... 

    Effect of potential on the early stage of nucleation and growth during aluminum electrocrystallization from molten salt (AlCl3-NaCl-KCl)

    , Article Journal of Electroanalytical Chemistry ; Volume 588, Issue 2 , 2006 , Pages 190-196 ; 15726657 (ISSN) Jafarian, M ; Mahjani, M. G ; Gobal, F ; Danaee, I ; Sharif University of Technology
    Elsevier  2006
    Abstract
    Electrodeposition of aluminum onto graphite from a molten electrolyte containing AlCl3-NaCl-KCl was studied by the method of chronoamperometery. In the early stage of the deposition and at low cathodic potentials two-dimensional (2D) nucleation and growth proceeding through instantaneous and a multitude of progressive steps followed the initial double layer charging. The processes are manifested as peaks on a decaying chronoamperogram. Non-linear fitting methods were applied to obtain the kinetic parameters in the light of Bewick, Fleischmann and Thirsk (BFT) theory. Under more cathodic potentials, transition from 2D to three-dimensional (3D) processes have been observed as manifested in the...