Search for: electrochemical-activities
0.006 seconds

    Novel magnetic flowable electrode for redox flow batteries: A polysulfide/iodide case study

    , Article Industrial and Engineering Chemistry Research ; Volume 60, Issue 2 , 2021 , Pages 824-841 ; 08885885 (ISSN) Rahimi, M ; Molaei Dehkordi, A ; Gharibi, H ; Roberts, E. P. L ; Sharif University of Technology
    American Chemical Society  2021
    A novel approach named a magnetic flowable electrode (MFE) is proposed for the first time to enable enhancement of redox flow batteries (RFBs) performance. This approach enables the formation of a high active surface area electrode from magnetic nanomaterials, without the need to fabricate a self-supporting three-dimensional electrode structure. To form a simple MFE, magnetic modified carbon nanotubes are dispersed in the electrolyte, and permanent magnets are embedded behind the current feeder to apply a magnetic field across the flow cell channels. With circulating electrolyte, magnetic carbon nanotubes are aggregated on the graphite bipolar plate to form a well-structured nanoscale... 

    Enhancement of Optical Absorption and Water Oxidation Reaction in One Dimensional Nanostructured Hematite Photoanodes

    , M.Sc. Thesis Sharif University of Technology Fathabadi, Milad (Author) ; Naseri, Naimeh (Supervisor)
    Hydrogen is known to be a renewable and clean source of energy, which produces water vapor and zero carbon dioxide as a result of its combustion. Photoelectrochemical water splitting (PEC) could be a promising approach in order to generate hydrogen by sunlight. Hematite (α-Fe2O3), as the most abundant naturally occurring form of iron oxide with suitable band gap, low cost, high stability and nontoxicity is considered to be an ideal photoanode. However, intrinsic drawbacks of hematite including low electrical conductivity, limited hole diffusion length, and high recombination rate of electron-hole pairs restrict its photoelectrochemical performance efficiency. In the present research,... 

    Adsorptive stripping differential pulse voltammetric determination of mebendazole at a graphene nanosheets and carbon nanospheres/chitosan modified glassy carbon electrode

    , Article Sensors and Actuators, B: Chemical ; Volume 185 , 2013 , Pages 669-674 ; 09254005 (ISSN) Ghalkhani, M ; Shahrokhian, S ; Sharif University of Technology
    For the first time graphene nanosheets and carbon nanospheres/chitosan (GNS-CNS/CS) based nanocomposite film modified electrode was used for the electro-oxidation of mebendazole (MD). MD is a benzimidazole drug that is used to treat human infections caused by parasitic worms. MD causes slow immobilization and death of the worms by selectively and irreversibly blocking uptake of glucose. The electrochemical behavior of MD at GNS-CNS/CS modified glassy carbon electrode has been investigated using cyclic and differential pulse voltammetry in aqueous media at different pHs. The prepared electrode showed an excellent electrochemical activity toward the electro-oxidation of MD leading to a... 

    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
    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... 

    RuO2/MWCNT/ stainless steel mesh as a novel positive electrode in vanadium redox flow batteries

    , Article RSC Advances ; Volume 5, Issue 84 , Aug , 2015 , Pages 68378-68384 ; 20462069 (ISSN) Gobal, F ; Faraji, M ; Sharif University of Technology
    Royal Society of Chemistry  2015
    The present work describes the preparation and electrochemical characterization of RuO2/MWCNT/Stainless Steel Mesh (SSM) electrode as compared with a MWCNT/SSM electrode in the positive half-cell of a Vanadium Redox Flow Battery (VRFB). The electrochemical characterization of prepared electrode was carried out using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge/discharge procedures. The electrochemical activity of MWCNT/SSM modified with RuO2 as positive electrode in a VRFB was notably improved. The RuO2-included electrodes demonstrated high peak current ratio, small peak potential difference and high electron... 

    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: 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... 

    Band-gap narrowing and electrochemical properties in N-doped and reduced anodic TiO2 nanotube arrays

    , Article Electrochimica Acta ; Volume 270 , 2018 , Pages 245-255 ; 00134686 (ISSN) Peighambardoust, N. S ; Khameneh Asl, S ; Mohammadpour, R ; Khameneh Asl, S ; Sharif University of Technology
    Elsevier Ltd  2018
    Electrochemical activity of TiO2 nanotube arrays (NTAs) is restricted by a wide band gap of TiO2. To overcome this restriction, we considered systematic research on two effective methods of doping of TiO2 NTAs such as the N-doping and electrochemical reductive doping and predicting the proper application of them. Band gap narrowing was occurred from 3.16 eV for undoped TiO2 NTAs to 2.9 and 2.7 eV at N-doped and self-doped TiO2 ones respectively. The electrochemical responses of the TiO2 NTAs before and after doping were examined by cyclic Voltammetry (CV) curve. To understand the electrochemical behavior of the undoped and doped TiO2 NTAs, electrochemical impedance spectroscopy (EIS) was... 

    Electrochemical study of Azathioprine at thin carbon nanoparticle composite film electrode

    , Article Electrochemistry Communications ; Volume 11, Issue 7 , 2009 , Pages 1425-1428 ; 13882481 (ISSN) Shahrokhian, S ; Ghalkhani, M ; Sharif University of Technology
    Thin carbon nanoparticle/Nafion film (CNP/N), as a novel electrode material, is formed on the surface of the glassy carbon electrode in a simple solvent evaporation process. The electrochemical behavior of Azathioprine (Aza) at the CNP/N-modified electrode is investigated in detail by the means of cyclic voltammetry. During the electrochemical reduction of Aza, an irreversible cathodic peak is appeared. Cyclic voltammetric studies indicated that the reduction process has an irreversible and adsorption-like behavior. The observed reduction peak is attributed to a four-electron process referring to the reduction of nitro group to the corresponding hydroxylamine. The prepared electrode showed... 

    Sensitive voltammetric detection of melatonin in pharmaceutical products by highly conductive porous graphene-gold composites

    , Article ACS Sustainable Chemistry and Engineering ; 2020 Rahmati, R ; Hemmati, A ; Mohammadi, R ; Hatamie, A ; Tamjid, E ; Simchi, A ; Sharif University of Technology
    American Chemical Society  2020
    This work presents a novel melatonin sensor based on unfunctionalized macroporous graphene networks decorated with gold nanoparticles for the differential pulse voltammetric detection of melatonin in pharmaceutical products. Highly porous graphene structures were prepared by metallic template-assisted chemical vapor deposition, and their active surface area and electrocatalytic activity were improved by electrochemical deposition of gold nanoparticles (50-250 nm) on their struts. The graphene-gold electrodes present a highly sensitive performance toward electro-oxidation of melatonin with a wide linear range of 0.05-50 μM, a low detection limit of 0.0082 μM (3σ/m), and a significant... 

    Effect of photoelectrochemical activity of ZnO-graphene thin film on the corrosion of carbon steel and 304 stainless steel

    , Article Journal of Materials Engineering and Performance ; Volume 29, Issue 1 , 2020 , Pages 497-505 Razavizadeh, O ; Bahadormanesh, B ; Ghorbani, M ; Simchi, A ; Sharif University of Technology
    Springer  2020
    In this research, the ZnOG hybrid thin film was produced via solgel method. The surface morphology, band gap and photoactive properties of the films were studied by means of SEM, UV–Vis and photoluminescence analysis. In addition, the ability of the thin film in photocathodic protection of carbon steel (CS) and 304 stainless steel in 3.5 wt.% NaCl and Na2S solutions under dark and UV illumination was investigated by polarization test as well as OCP and current measurements during coupling of steels with ZnOG photoanode. The mix band gap is reduced to the orders of 1.17 eV through hybridization of ZnO with graphene oxide. In both NaCl and Na2S solutions, the ZnOG thin film could effectively... 

    Highly sensitive voltammetric determination of lamotrigine at highly oriented pyrolytic graphite electrode

    , Article Bioelectrochemistry ; Volume 84 , 2012 , Pages 38-43 ; 15675394 (ISSN) Saberi, R. S ; Shahrokhian, S ; Sharif University of Technology
    The electrochemical behavior of lamotrigine (LMT) at the pyrolytic graphite electrode (PGE) is investigated in detail by the means of cyclic voltammetry. During the electrochemical reduction of LMT, an irreversible cathodic peak appeared. Cyclic voltammetric studies indicated that the reduction process has an irreversible and adsorption-like behavior. The observed reduction peak is attributed to a two-electron process referring to the reduction of azo group. The electrode showed an excellent electrochemical activity toward the electro-reduction of LMT, leading to a significant improvement in sensitivity as compared to the glassy carbon electrode. The results of electrochemical impedance...