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Total 108 records

    Hydrogen electrosorption on TiHg alloy in acidic solution

    , Article Journal of Alloys and Compounds ; Volume 432, Issue 1-2 , 2007 , Pages 74-80 ; 09258388 (ISSN) Jafarian, M ; Azizi, O ; Gobal, F ; Mahjani, M. G ; Sharif University of Technology
    2007
    Abstract
    Hydrogen evolution and electrosorption on/in TiHg alloy have been investigated in acidic solution using cyclic voltammetry, open circuit potential transient, steady-state polarization, chronopotentiometry and electrochemical impedance measurements. Comparison has been made with pure Ti. Cyclic voltammetry and open circuit potential measurements show that hydrogen absorption into the electrode material occurs during proton discharge. The steady-state polarization curves in the course of positive and negative potential scans illustrate that the formation of absorbed hydrogen slightly improves the electrocatalytic properties of the electrode. The hydrogen diffusion coefficient into the bulk of... 

    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) Nozad Golikand, A ; 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... 

    Fabrication of self-organised highly ordered titanium oxide nanotube arrays by anodic oxidation and characterisation

    , Article International Journal of Nanomanufacturing ; Volume 5, Issue 3-4 , 2010 , Pages 297-309 ; 17469392 (ISSN) Mohammadpour, R ; Ahadian, M. M ; Iraji Zad, A ; Taghavinia, N ; Dolati, A. G ; Sharif University of Technology
    2010
    Abstract
    Self-organised and vertically oriented titanium oxide nanotube array (TNTA) has been synthesised by potentiostat anodisation of Ti foil in fluoride-based electrolyte. By varying the anodisation voltage from 8 V to 24 V it was possible to gradually change the topologies of nanotubes. The size of TNTAs was measured using SEM images and also determined based on a non-destructive optical method. In addition, photoelectrochemical properties of nanotubular TiO2/Ti electrodes were examined by anodic photocurrent response, potentiodynamic polarisation measurements and electrochemical impedance spectroscopy. A general equivalent circuit model was proposed for photoelectrochemical system consists of... 

    On the pseudocapacitive behavior of nanostructured molybdenum oxide

    , Article Journal of Solid State Electrochemistry ; Volume 14, Issue 4 , 2010 , Pages 643-650 ; 14328488 (ISSN) Farsi, H ; Gobal, F ; Raissi, H ; Moghiminia, S ; Sharif University of Technology
    Abstract
    Nanostructured molybdenum oxide was potentiodynamically deposited onto a stainless steel surface from an aqueous bath by cycling the potential between 0 and -0.75 V vs. Ag/AgCl. The deposit consisted of particulates in the range of 30 to 80 nm. Electrochemical studies under galvanostatic charge/discharge and also impedance spectroscopy revealed capacitive behavior in the potential range of -0.3 to -0.55 V vs. Ag/AgCl with the value of 477 F g-1 at 0.1 mA/cm2. An equivalent circuit comprising of three parallel branches consisting of double-layer capacitance, Warburg impedance, and a constant phase element signifying pseudo-capacitance each coupled with their corresponding resistances was... 

    Facile synthesis of nanoporous CuS nanospheres for high-performance supercapacitor electrodes

    , Article Journal of Energy Chemistry ; Volume 26, Issue 4 , 2017 , Pages 762-767 ; 20954956 (ISSN) Heydari, H ; Moosavifard, S. E ; Shahraki, M ; Elyasi, S ; Sharif University of Technology
    Abstract
    In recent years, development of high-performance supercapacitor electrode materials has stimulated a great deal of scientific research. The electrochemical performance of a supercapacitor strongly depends on its material structures. Herein, we report a simple strategy for high-performance supercapacitors by building pseudocapacitive CuS nanospheres with nanoporous structures, nanosized walls (<10 nm) and relatively large specific surface area of 65 m2/g. This electrode demonstrates excellent electrochemical performance including a maximum specific capacitance of 814 F/g at 1 A/g, significant rate capability of 42% capacitance retention at an ultrafast rate of 50 A/g, and outstanding... 

    Electron transport phenomenon simulation through the carborane nano-molecular wire

    , Article Physica E: Low-Dimensional Systems and Nanostructures ; Volume 40, Issue 9 , August , 2008 , Pages 2965-2972 ; 13869477 (ISSN) Aghaie, H ; Gholami, M. R ; Monajjemi, M ; Ganji, M. D ; Sharif University of Technology
    2008
    Abstract
    The electron transport characteristics of a 1,10-dimethylene-1,10-dicarba-closo-decaborane (10-vertex carborane) single molecular conductor is investigated via the density functional-based non-equilibrium Green's function (DFT-NEGF) method. We consider three configurations for the molecular wire sandwiched between two Au(1 0 0) electrodes: the hollow site, top site and bridge site positions. Our results show that the energetically favorable hollow site configuration has a higher current intensity than the other configurations. The projection of the density of states (PDOS) and the transmission coefficients T(E) of the two-probe system at zero bias are analyzed, and it suggests that the... 

    Carbon paste electrode incorporating multi-walled carbon nanotube/cobalt salophen for sensitive voltammetric determination of tryptophan

    , Article Sensors and Actuators, B: Chemical ; Volume 123, Issue 2 , 2007 , Pages 942-949 ; 09254005 (ISSN) Shahrokhian, S ; Fotouhi, L ; Sharif University of Technology
    2007
    Abstract
    A modified carbon paste electrode is prepared by incorporating multi-walled carbon nanotube (MWCNT) and cobalt salophen (CoSal). A mixture of fine graphite powder with 10 wt% of MWCNT is applied for the preparation of carbon paste (by dispersing in Nujol) and finally modified with CoSal. The electrocatalytic oxidation of tryptophan (Trp) is investigated on the surface of the MWCNT/CoSal-modified electrode using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Using the modified electrode, the kinetics of the electro-oxidation of Trp is considerably enhanced, by lowering the anodic overpotential through a catalytic fashion. The mechanism of electrochemical behavior of Trp at... 

    Nano composite coating based on cellulose nanofibers/carbon nanoparticles: application to voltammetric determination of clonazepam

    , Article Journal of Solid State Electrochemistry ; Vol. 19, issue. 1 , 2014 , p. 251-260 Shahrokhian, S ; Balotf, H ; Ghalkhani, M ; Sharif University of Technology
    Abstract
    A novel electrochemical sensor for clonazepam (CLNP) was fabricated based on immobilizing cellulose nanofibers/carbon nanoparticles (CNFs/CNPs) nanocomposite on glassy carbon electrode (CNFs/CNPs/GCE). The combination of CNFs and CNPs produced a novel kind of structurally uniform and electro-analytically active nanocomposite. The surface morphology of CNFs/CNPs layer deposited onto glassy carbon electrode was characterized by scanning electron microscopy. The results of the voltammetric investigations showed a considerable enhancement in the cathodic peak current of CLNP (up to 60 times) on the surface of CNFs/CNPs/GCE relative to the bare GCE. Under the optimal conditions, the modified... 

    Copper corrosion in sodium dodecyl sulphate solutions and carbon nanotube nanofluids: A modified Koutecky-Levich equation to model the agitation effect

    , Article Corrosion Science ; Volume 53, Issue 12 , December , 2011 , Pages 4241-4247 ; 0010938X (ISSN) Baghalha, M ; Kamal Ahmadi, M ; Sharif University of Technology
    2011
    Abstract
    Copper corrosion in sodium dodecyl sulphate (SDS) solutions and carbon nanotube (CNT) nanofluids were studied by potentiodynamic polarization. For the corrosion current densities calculations, Koutecky-Levich equation was modified to model the combined charge and mass transport. 0.005. M SDS reduced the copper corrosion current density by 81%. Higher SDS concentrations enhanced corrosion. Stirring SDS solutions increased the corrosion current density by ∼75%. By adding CNT to SDS solution, the corrosion current density first decreased and then remained constant. Stirring CNT nanofluids didn't change the corrosion current density. An adsorbed CNT layer on copper controlled the corrosion... 

    Application of glassy carbon electrode modified with a carbon nanoparticle/melamine thin film for voltammetric determination of raloxifene

    , Article Journal of Electroanalytical Chemistry ; Volume 780 , 2016 , Pages 126-133 ; 15726657 (ISSN) Shahrokhian, S ; Ghalkhani, M ; Balotf, H ; Salimian, R ; Sharif University of Technology
    Elsevier B.V  2016
    Abstract
    As a selective estrogen receptor modulator, raloxifene (RXF) prevent of osteoporosis in postmenopausal women by estrogenic actions on bone and decreases the risk of invasive breast cancer by anti-estrogenic actions on the breast and uterus tissue. However, RXF may increase the risk of blood clots, including deep vein thrombosis and pulmonary embolism. For the first time glassy carbon electrode modified with a thin film of melamine/carbon nanoparticles (CNPs/Mela) was constructed and used for the sensitive voltammetric determination of RXF. In comparison with unmodified electrode, the presence of the CNPs/Mela film resulted in a remarkable increase in the peak currents and sharpness of the... 

    One-step fabrication of electrochemically reduced graphene oxide/nickel oxide composite for binder-free supercapacitors

    , Article International Journal of Hydrogen Energy ; Volume 41, Issue 39 , 2016 , Pages 17496-17505 ; 03603199 (ISSN) Shahrokhian, S ; Mohammadi, R ; Asadian, E ; Sharif University of Technology
    Elsevier Ltd  2016
    Abstract
    A three-dimensional (3D) graphene/Nickel oxide (ERGO/NiO) composite electrode have been fabricated directly on a Nickel foam substrate via a one-step electrochemical co-deposition in an aqueous solution containing Nickel nitrate and GO. By using this simple and one-step electrochemical deposition, it is possible to produce binder-free composite electrodes with improved electrochemical properties using a low-cost, facile and scalable technique. It is observed from FE-SEM images that graphene oxide sheets affect the electrodeposition of nickel oxide. The optimized ErGO/NiO electrode developed in this work exhibits high charge storage capacity with a specific capacitance of 1715.5 F g−1 at... 

    ZnO-PEDOT core-shell nanowires: An ultrafast, high contrast and transparent electrochromic display

    , Article Solar Energy Materials and Solar Cells ; Volume 145 , 2016 , Pages 200-205 ; 09270248 (ISSN) Kateb, M ; Safarian, S ; Kolahdouz, M ; Fathipour, M ; Ahamdi, V ; Sharif University of Technology
    Elsevier 
    Abstract
    We report fabrication of ultrafast and high contrast transparent electrochromic device desired for display application using nanostructured electrode. To this end, poly (3,4-ethylenedioxythiophene) (PEDOT) nanotubes were synthesized by simple electrochemical polymerization method on hydrothermally grown ZnO nanowires array as electrode. The PEDOT nanotubes of 20 nm average wall thickness characterized by SEM, TEM and EDS. The manufactured cell was subjected to electrochemical test and spectrophotometery that showed high contrast of 54% during ultrafast switching time of <2.2 ms. In addition, high coloration efficiency of 234 cm2/C, ultrahigh diffusion coefficient of 2.01×10-4 cm2/s and... 

    Glassy carbon electrode modified with 3D graphene–carbon nanotube network for sensitive electrochemical determination of methotrexate

    , Article Sensors and Actuators, B: Chemical ; Volume 239 , 2017 , Pages 617-627 ; 09254005 (ISSN) Asadian, E ; Shahrokhian, S ; Iraji Zad, A ; Ghorbani Bidkorbeh, F ; Sharif University of Technology
    Elsevier B.V  2017
    Abstract
    In the present study, a 3D porous graphene-carbon nanotube (G-CNT) network is successfully constructed on the surface of glassy carbon electrode (GCE) by electrochemical co-deposition from a concentrated graphene dispersion. The large accessible surface area provided by the interpenetrated graphene backbone in one hand and the enhanced electrical conductivity of the 3D network by incorporating CNTs on the other hand, dramatically improved the electrochemical performance of GCE in determination of Methotrexate (MTX) as an important electroactive drug compound. Under the optimum conditions, the electrode modification led to a significant increase in the anodic peak current (∼25 times) along... 

    Nanoporous CuS nano-hollow spheres as advanced material for high-performance supercapacitors

    , Article Applied Surface Science ; Volume 394 , 2017 , Pages 425-430 ; 01694332 (ISSN) Heydari, H ; Moosavifard, S. E ; Elyasi, S ; Shahraki, M ; Sharif University of Technology
    Elsevier B.V  2017
    Abstract
    Due to unique advantages, the development of high-performance supercapacitors has stimulated a great deal of scientific research over the past decade. The electrochemical performance of a supercapacitor is strongly affected by the surface and structural properties of its electrode materials. Herein, we report a facile synthesis of high-performance supercapacitor electrode material based on CuS nano-hollow spheres with nanoporous structures, large specific surface area (97 m2 g−1) and nanoscale shell thickness (<20 nm). This interesting electrode structure plays a key role in providing more active sites for electrochemical reactions, short ion and electron diffusion pathways and facilitated... 

    Fabrication and the electrochemical activation of network-like MnO2 nanoflakes as a flexible and large-area supercapacitor electrode

    , Article Journal of Solid State Electrochemistry ; Volume 22, Issue 11 , 2018 , Pages 3507-3514 ; 14328488 (ISSN) Mardi, S ; Moradlou, O ; Moshfegh, A. Z ; Sharif University of Technology
    Abstract
    Porous network-like MnO2 thick films are successfully synthesized on a flexible stainless steel (SS) mesh using a simple and low-cost electrodeposition method followed by an electrochemical activation process. Morphology, chemical composition, and crystal structure of the prepared electrodes before and after the activation process are determined and compared by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) analyses. The results show that the implementation of the electrochemical activation process does not change the chemical composition and crystal structure of the films, but it influences the surface morphology of the MnO2... 

    Electrochemical sensing based on carbon nanoparticles: A review

    , Article Sensors and Actuators, B: Chemical ; Volume 293 , 2019 , Pages 183-209 ; 09254005 (ISSN) Asadian, E ; Ghalkhani, M ; Shahrokhian, S ; Sharif University of Technology
    Elsevier B.V  2019
    Abstract
    The emergence of nanoscience and nanotechnology has opened up new horizons to researchers. In this regard, carbon nanomaterials are considered as the cornerstone of numerous investigations. Among various carbon nanostructures, “Carbon nanoparticles (CNPs)” have attracted a great deal of attention during the past few years due to their unique properties such as high surface area, non-toxicity, biocompatibility as well as simple and low-cost synthetic procedures via environmentally friendly routes. Thanks to these properties along with their interesting optical behavior, CNPs have found diverse applications in the fields of bioimaging, nanomedicine, photo/electro-catalysis, and bio/chemical... 

    Size and geometry of multielectrode arrays determine the efficiency of electrical interaction with neurons through double-layer capacitance

    , Article IEEE Sensors Journal ; Volume 19, Issue 8 , 2019 , Pages 2829-2836 ; 1530437X (ISSN) Vafaiee, M ; Mohammadpour, R ; Vossoughi, M ; Sasanpour, P ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2019
    Abstract
    Multielectrode array (MEA) structures are the vital parts in the interface between neural structures and external electronic circuits, both in excitation and detection. As a transducer, the performance of electrodes has direct effect on the quality of the recorded neural signal, as well as induced charge density during the stimulation in neural prosthesis. The size and geometry of the electrode structure have distinct effect on the performance of electrodes accordingly. In this paper, the effect of size and geometry of the electrodes has been investigated in their performance and the impedimetric features of the fabricated electrodes with different structures have been studied. Based on the... 

    A stable and high-energy hybrid supercapacitor using porous Cu2O-Cu1.8S nanowire arrays

    , Article Journal of Materials Chemistry A ; Volume 8, Issue 4 , 2020 , Pages 1920-1928 Esfandiar, A ; Qorbani, M ; Shown, I ; Ojaghi Dogahe, B ; Sharif University of Technology
    Royal Society of Chemistry  2020
    Abstract
    A three-dimensional electrode based on porous Cu2O-Cu1.8S nanowires is prepared by means of a facile fabrication process. In this electrode, nanowires are decorated with Cu1.8S polyhedral nanostructures on the top, which are directly grown on a copper foam, thereby eliminating the need for a polymer binder. As an electrochemical electrode, it exhibits an extrinsic pseudocapacitive charge storage mechanism, which is different from that of battery-like Cu2O-CuO and Cu(OH)2 electrodes. The areal and volumetric capacitances of the Cu2O-Cu1.8S electrode can reach 2.6 F cm-2 and ∼200 F cm-3, respectively, at 2 mA cm-2, which are much higher than those obtained using copper(i, ii) oxide and... 

    Composites of reduced graphene oxide/nickel submicrorods for non-enzymatic electrochemical biosensing: application to amperometric glucose detection

    , Article Journal of the Electrochemical Society ; Volume 167, Issue 8 , 2020 Mohammadzadeh, A ; Mazaheri, M ; Sedighian, A ; Ghanbari, H ; Simchi, A ; Sharif University of Technology
    Institute of Physics Publishing  2020
    Abstract
    For the rapid detection of hyperglycemia in human blood, we adopted a facile and two-step electrochemical procedure to prepare nickel/reduced graphene oxide (rGO) hybrid electrodes in the framework of a three-dimensional (3D) nanostructure. High-density and vertically-aligned nickel submicrorods with an average diameter of 155 ± 15 nm and a length of 7 ± 1 μm (an aspect ratio of about 40-50) were prepared by template-mediated electrochemical deposition techniques. Networks of rGO nanosheets between the rod-shaped arrays were formed by the cathodic electrophoretic deposition method. The synergistic effect of nickel morphology (planar and high-density rod-shaped arrays) and graphene oxide... 

    Enhanced Activity of Pr6O11 and CuO Infiltrated Ce0.9Gd0.1O2 Based Composite Oxygen Electrodes

    , Article Journal of the Electrochemical Society ; Volume 167, Issue 2 , January , 2020 Khoshkalam, M ; Faghihi Sani, M. A ; Tong, X ; Chen, M ; Hendriksen, P. V ; Sharif University of Technology
    Institute of Physics Publishing  2020
    Abstract
    Operation of solid oxide fuel/electrolysis cells (SOFC/SOEC) at high temperatures (T > 850 °C) is accompanied by degradation phenomena, which severely affect the operational lifetime of the cell. Degradation processes are expected to occur slower at low temperatures. However, significant reduction in electrocatalytic activity of the oxygen electrode, is one of the major challenges in decreasing the operating temperature down to 500 °C-650 °C. Recently, Pr6O11 infiltrated Ce0.9Gd0.1O2 (CGO) based electrodes have been proposed to realize high electrochemical performance at intermediate temperature. In this study, Pr-oxide has been infiltrated into a well performing sub-micro...