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    Electrodeposition of Rhenium and Nickel Nanoparticles

    , M.Sc. Thesis Sharif University of Technology Ataee, Hamed (Author) ; Sadrnezhad, Khatiboleslam (Supervisor)
    Abstract
    In the last decade, a great deal of attention has been paid to the study of synthesis of Nanoparticles, because of the widespread use of this material in applications involving Fuel cells and magnetic devices. In this thesis, we report some interesting features in the electrodeposition of metallic nanoparticles. The electrochemical phase formation of rhenium and nickel on the surface of P-Si (100) substrate plus morphological, topographical and fractal aspects of the accumulated surface were investigated in this research by means of chronoamperometry method and by utilization of AFM and SEM. The nucleation and growth mechanisms on silicon electrode are characterized using cyclic voltammetry... 

    The electrocatalytic examination of cephalosporins at carbon paste electrode modified with CoSalophen

    , Article Talanta ; Volume 71, Issue 4 , 2007 , Pages 1669-1674 ; 00399140 (ISSN) Jamasbi, E. S ; 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... 

    , M.Sc. Thesis Sharif University of Technology Oghbaei, Shabnam (Author) ; Ghabl, Feridon (Supervisor)
    Abstract
    The purpose of this study is to investigate the effect of halids on electrooxidation of silver in alkalie medium. For this case, electrochemical teqniques such as Chronoamperometery (CA) and Cyclic Voltammetry (CV) were applied. Characterization of the electrodeposition process is based on quantitative analysis of the potentiostatic current versus time curves. Rate constants of nucleation and growth obtained from the fit of the recorded transients to the generalized equations derived based on Abyaneh and Flischmann model. The conditions that justify the use of the limiting forms of the transient equations for the so-called “ instantaneous” and “ progressive” nucleation processes were... 

    Electrodeposition of platinum nanowires: Electrochemical characterization

    , Article ECS Transactions, 25 April 2010 through 30 April 2010 ; Volume 28, Issue 18 , April , 2010 , Pages 25-35 ; 19385862 (ISSN) ; 9781607681946 (ISBN) Mahshid, S. S ; Dolati, A ; Hashemi Daryan, S ; Ghorbani, M ; Ghahramaninezhad, A ; Physical and Analytical Electrochemistry ; Sharif University of Technology
    2010
    Abstract
    Platinum nanowires (PtNWs) were electrodeposited on the polycarbonate templates (PCTs) in aqueous solution of H2PtCl6 in triply distilled water. Nanowires with diameters of 50 and 100 nanometers were electrodeposited on the same condition. The kinetics of electrodeposition process was studied by electrochemical techniques such as voltammetry and chronoamperometry methods. Increasing the scan rate, the peaks shifted to more negative potentials and the current density also increased in each peak which was typical for a diffusion-control process. The potential range for the deposition of platinum nanowires was specified and consequently the potentiostatic i-t transients were utilized to produce... 

    MWCNT/WO3 nanocomposite photoanode for visible light induced water splitting

    , Article Journal of Solid State Chemistry ; Volume 204 , 2013 , Pages 341-347 ; 00224596 (ISSN) Yousefzadeh, S ; Reyhani, A ; Naseri, N ; Moshfegh, A. Z ; Sharif University of Technology
    2013
    Abstract
    The Multi-walled carbon nanotube (MWCNT)/WO3 nanocomposite thin films with different MWCNT's weight percentages were prepared by sol-gel method as visible light induced photoanode in water splitting reaction. Weight percentage of MWCNT in the all nanocomposite thin films was confirmed by TGA/DSC analysis. According to XPS analysis, oxygenated groups at the surface of the MWCNT and stoichiometric formation of WO3 thin films were determined, while the crystalline structure of the nanocomposite samples was studied by XRD indicating (0 0 2) peak of MWCNT in the monoclinic phase of WO3. The influence of different weight percentage (wt%) of MWCNT on WO3 photoactivity showed that the electron... 

    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... 

    Electrocrystallization of Ni nanocones from chloride-based bath using crystal modifier by electrochemical methods

    , Article Journal of Alloys and Compounds ; Volume 818 , 2020 Barati Darband, G ; Aliofkhazraei, M ; Dolati, A ; Rouhaghdam, A. S ; Sharif University of Technology
    Elsevier Ltd  2020
    Abstract
    The early stages of nucleation and growth of nanostructures can control the shape and final size of the fabricated nanostructure. Therefore, the study of the nucleation and growth mechanism of nanostructures is of great importance. The purpose of this study is to investigate the nucleation and growth mechanism of nickel nanocones from a chloride-based bath containing ethylene ammonium dichloride as a crystal modifier. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and chronoamperometry tests were employed to investigate the nucleation and growth mechanism and also the mechanism of crystal modifier performance on the growth of nanocones. Electrochemical studies revealed... 

    Electrochemical characterization of electrodeposited carbon nanotubes

    , Article Thin Solid Films ; Volume 519, Issue 19 , July , 2011 , Pages 6230-6235 ; 00406090 (ISSN) Fayazfar, H ; Dolati, A ; Ghorbani, M ; Sharif University of Technology
    2011
    Abstract
    Carbon nanotubes were electrodeposited in acetonitrile solution at room temperature using Cu, and Fe-Ni nanoparticles as nucleation sites on HF-etched Si(100) wafer substrate. The electrochemical behavior of the deposition was investigated by voltammetry and chronoamperometry techniques. In order to obtain the optimum growth condition, the deposition critical parameters including current density range, potential and time were studied and calculated. Carbon nanotubes with approximate external diameter of 40-100 nm were fabricated under potentiostatic condition and diffusion control at - 20 V in 4-6 h. The film crystallinity was investigated by means of X-ray diffraction and the tubes... 

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

    , Article International Journal of Hydrogen Energy ; Volume 33, Issue 16 , August , 2008 , Pages 4367-4376 ; 03603199 (ISSN) Danaee, I ; Jafarian, M ; Forouzandeh, F ; Gobal, F ; Mahjani, M. G ; Sharif University of Technology
    2008
    Abstract
    Nickel and nickel-copper alloy modified glassy carbon electrodes (GC/Ni and GC/NiCu) prepared by galvanostatic deposition were examined for their redox process and electrocatalytic activities towards the oxidation of methanol in alkaline solutions. The methods of cyclic voltammetery (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. In CV studies, in the presence of methanol NiCu alloy modified electrode shows a significantly higher response for methanol oxidation. The peak current of the oxidation of nickel... 

    Fabrication of Nanocomposite Modified Materials Based on Bi-Metalic Transition Metal Sulfide Using Copper (I) Oxide Nanospheres as a Catalytic Substrate for Designation of Amperometric Non-Enzymatic Hydrazine and Hydrogen peroxide Sensors

    , M.Sc. Thesis Sharif University of Technology Darvishmehr, Zahra (Author) ; Shahrokhian, Saeed (Supervisor)
    Abstract
    In this study, transition metal sulfide, with a high accessible surface and abundant electroactive centers, was used as an electrocatalyst to fabrication an electrochemical sensor of hydrazine and hydrogen peroxide. the direct growth of thin film of nanocomposite can be considered as an efficient method to modify the electrode surface, and the application of these modified electrodes as electrochemical sensors. the cobalt iron sulfide (CoFeS) nanosheets were directly grown on Cu2O nanospheres in order to design hierarchical nanocomposite by using efficient, inexpensive and fast method. Here, Cu2O nanospheres not only served as substrate, but also steer the CoFeS to attach on nanospheres... 

    Microstructure, mechanical properties, corrosion behavior and cytotoxicity of Mg-Zn-Al-Ca alloys as biodegradable materials

    , Article Journal of Alloys and Compounds ; Vol. 607 , 2014 , Pages 1-10 ; ISSN: 09258388 Homayun, B ; Afshar, A ; Sharif University of Technology
    Abstract
    Recently, considerable attentions have been paid to alloy Mg-4Zn-0.2Ca for biomedical applications due to its suitable biocompatibility and acceptable mechanical properties. In this work, the effects of the addition of different amounts of Al on microstructure, mechanical properties, degradation behavior, and biocompatibility of this alloy were investigated. The corrosion behaviors of the alloys were investigated through polarization tests, chronoamperometry analysis, immersion tests, and EIS experiments. The mechanical properties were analyzed by using tensile tests and compression tests. The results showed that the addition of Al up to 3 wt.% considerably modifies the degradation behaviors... 

    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... 

    The effect of cysteine on electrodeposition of gold nanoparticle

    , Article Materials Science and Engineering B: Solid-State Materials for Advanced Technology ; Volume 176, Issue 16 , 2011 , Pages 1307-1312 ; 09215107 (ISSN) Dolati, A ; Imanieh, I ; Salehi, F ; Farahani, M ; Sharif University of Technology
    2011
    Abstract
    The most applications of gold nanoparticles are in the photo-electronical accessories and bio-chemical sensors. Chloride solution with cysteine additive was used as electrolyte in gold nanoparticles electrodeposition. The nucleation and growing mechanism were studied by electrochemical techniques such as cyclic voltammetry and chronoamperometry, in order to obtain a suitable nano structure. The deposition mechanism was determined as instantaneous nucleation and the dimension of particles was controlled in nanometric particle size range. Atomic Force Microscope was used to evaluate the effect of cysteine on the morphology and topography of gold nanoparticles. Finally the catalytic property of... 

    Synergistic effect of cobalt and copper on a nickel-based modified graphite electrode during methanol electro-oxidation in NaOH solution

    , Article Cuihua Xuebao/Chinese Journal of Catalysis ; Volume 36, Issue 11 , 2015 , Pages 1867-1874 ; 02539837 (ISSN) Rostami, T ; Jafarian, M ; Miandari, S ; Mahjani, M. G ; Gobal, F ; Sharif University of Technology
    Abstract
    The electrocatalytic oxidation of methanol was studied over Ni, Co and Cu binary or ternary alloys on graphite electrodes in a NaOH solution (0.1 mol/L). The catalysts were prepared by cycling the graphite electrode in solutions containing Ni, Cu and Co ions at cathodic potentials. The synergistic effects and 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 methanol, the modified Ni-based ternary alloy electrode (G/NiCuCo) exhibited a significantly higher response for methanol oxidation compared to the other samples. The anodic peak... 

    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... 

    A preliminary study of the electro-oxidation of l-ascorbic acid on polycrystalline silver in alkaline solution

    , Article Journal of Power Sources ; Volume 195, Issue 1 , 2010 , Pages 165-169 ; 03787753 (ISSN) Majari Kasmaee, L ; Gobal, F ; Sharif University of Technology
    2010
    Abstract
    Electrochemical oxidation of l-ascorbic acid on polycrystalline silver in alkaline aqueous solutions is studied by cyclic voltammetry (CV), chronoamperometry (CA) and impedance spectroscopy (IS). The anodic electro-oxidation starts at -500 mV versus SCE and shows continued anodic oxidation in the cathodic half cycle in the CV regime signifying slowly oxidizing adsorbates. Diffusion coefficient of ascorbate ion measured under both voltammetric regimes is around 1.4 × 10-5 cm2 s-1. Impedance spectroscopy measures the capacitances associated with double layer and adsorption around 50 μF cm-2 and 4 mF cm-2 as well as the adsorption and decomposition resistances (rates). © 2009 Elsevier B.V. All... 

    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) Jafarian, M ; 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... 

    Electrochemical investigation of electrodeposited platinum nanoparticles on multi walled carbon nanotubes for methanol electro-oxidation

    , Article Journal of Chemical Sciences ; Volume 129, Issue 9 , 2017 , Pages 1399-1410 ; 09743626 (ISSN) Mokarami Ghartavol, H ; Moakhar, R. S ; Dolati, A ; Sharif University of Technology
    Abstract
    Abstract: The electrodeposition of platinum nanoparticles (PtNPs) on multiwall carbon nanotubes (MWCNTs)/fluorine-doped tin oxide glass (FTO) was investigated. Nucleation and growth mechanisms were studied via Scharifker and Hills model. Chronoamperometry results clearly show that the electrodeposition processes are diffusion-controlled and the diffusion coefficient is 1.5×10-5cm2/s. The semi-spherical particles with lamellar morphology were observed in 1M H 2SO 4, while a petal shape was discerned in 0.5M H 2SO 4. Also, dispersion, size, and uniformity of PtNPs were investigated, where the finer distribution of PtNPs with the average size less than 100 nm was obtained in 0.5M H 2SO 4... 

    Selective storage and evolution of hydrogen on nafion/NaCl/graphene quantum dot mixed matrix using tensammetry as power electrochemical technique

    , Article International Journal of Hydrogen Energy ; Volume 42, Issue 15 , 2017 , Pages 9428-9439 ; 03603199 (ISSN) Deylaminezhad, M ; Zakipour, M ; Doroodmand, M. M ; Mehrtash, M ; Sharif University of Technology
    Abstract
    Hydrogen storage/evolution behavior of nafion/NaCl/graphene quantum dot (GQD) mixed matrix as selective hydrogen capacitor (power source) was evaluated in detail through an electrochemical process at two independent potential ranges. For this purpose, a three-electrode system included Pt disk as counter electrode, Ag/AgCl as reference electrode and GQD-based mixed matrix-modified Pt disk as working electrode. For hydrogen storage, the deposition potential and time were evaluated to −1.0 V (vs. Ag/AgCl) and 120 s, respectively under high basic solution generated using NaOH (1.0 M) solution, followed by evolution of hydrogen at +0.8 V (vs. Ag/AgCl) during formation of hydrogen bubbles. The...