Search for: cyclic-voltammetry
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    Electrochemical deposition of flower-like nickel nanostructures on well-defined n-si(111):h

    , Article International Journal of Engineering, Transactions B: Applications ; Volume 21, Issue 2 , 2008 , Pages 177-182 ; 1728-144X (ISSN) Torabi, M ; Khalifehzadeh, R ; Arami, H ; Sadrnezhaad, S. K ; Sharif University of Technology
    Materials and Energy Research Center  2008
    In this paper the electrodeposition of nickel on n-Si(111):H substrate, in the presence of sulphuric acid, was studied. Cyclic voltammetry has been used to characterize the electrochemical behavior of the system. The nickel deposits had a flower-like morphology with the spherical nanostructure nucleus, distributed uniformly on the surfaces of the prepared n-Si(111) substrate  

    A study on mutual interaction between atomistic and macroscopic phenomena during electrochemical processes using FD-KMC model: Application to CV test in simple copper sulfate bath

    , Article Journal of Electroanalytical Chemistry ; Volume 592, Issue 1 , 2006 , Pages 95-102 ; 15726657 (ISSN) Saedi, A ; Sharif University of Technology
    Elsevier  2006
    A multiscale FD-KMC model has been developed to simulate the cyclic voltammetry test of a copper electrode in simple copper sulfate bath. In this coupled model, the FD code provides the cupric ion concentration on OHP for KMC code, while the KMC code provides the electrochemical properties of the copper electrode (surface activity and rate constants of redox reactions) as an input data for FD code. The changes in the electrode properties due to the atomistic phenomena (deposition dissolution and surface diffusion) have been studied for the present potentiodynamic system. The results showed that the CV process consists of some distinct stages, so that the electrode exhibits a specific... 

    Hybrid of cerium dioxide nanoparticles/reduced graphene oxide as an electrode material for supercapacitor applications

    , Article Journal of Physics and Chemistry of Solids ; Volume 159 , 2021 ; 00223697 (ISSN) Salarizadeh, P ; Askari, M. B ; Beydaghi, H ; Rastgoo Deylami, M ; Rozati, S. M ; Sharif University of Technology
    Elsevier Ltd  2021
    In this study, we prepared cerium oxide (CeO2) hybridized with reduced graphene oxide (rGO) nanosheets using the hydrothermal method. CeO2 and CeO2/rGO were evaluated as electrode materials for use in supercapacitor applications. The structure and morphology of the synthesized materials were investigated. Cyclic voltammetry tests determined a high specific capacitance of 581 F g−1 for CeO2/rGO at a scan rate of 10 mV s−1 in 2 M KOH. In addition, the CeO2/rGO electrode retained 91 % of its initial capacitance after 5000 consecutive cycles, thereby indicating its excellent electrochemical stability. The excellent stability of CeO2/rGO was due to a synergistic effect between CeO2 and rGO. CeO2... 

    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
    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... 

    Chemical Modification of Glassy Carbon Electrode by Carbon Nanostructures/Conductive Polymers Composites and Its Application in The Study of Electrochemical Behaviour and Determination of Salbutamol and Isoprenaline

    , M.Sc. Thesis Sharif University of Technology Panahi, Saba (Author) ; Shahrokhian, Saeed (Supervisor)
    In the first part of thesis, the electropolymerization of pyrrole was performed in the presence of new coccine (NC) as a dopant anion on the surface of the electrode precoated with SWCNT. The modified electrode was used to study the voltammetric response of salbutamol (SAL). The results showed a remarkable increase in the anodic peak current of SAL in comparison to the bare GCE. The surface morphology PPY/CNT/GCE was thoroughly characterized by scanning electron microscopy (SEM) and cyclic voltammetry (CV) techniques. Under the optimized analysis conditions, the modified electrode showed two linear dynamic ranges of 0.02 – 0.1 μM and 0.1-10 μM with a detection limit of 6 nM for the... 

    Preparation and Study of the Electrochemical Ptal Oxide Particles/Carbon Nanoparticles: Application to Pharmaceutical Determinations

    , M.Sc. Thesis Sharif University of Technology Kohansal, Razieh (Author) ; Shahrokhian, Saeed (Supervisor)
    In the first work, a novel voltammetric biosensor basedon TiO2-nafion-carbon nanoparticles modified glassy carbon electrode (TiO2/N/CNP/GCE) was developed for the determination of DBA. The electrochemical performance of the modified electrode was investigated by means of cyclic voltammetry (CV), different pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) techniques. Characterization of the surface morphology and properties of TiO2/N/CNP was carried out by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Effective experimental variables, such as scan rate, pH of the supporting electrolyte, drop size of the cast modifier suspension and accumulation... 

    Chemically Modified Electrodes Based on Conducting Polymers and Carbon Nanotubes: Application to Voltammetric Determination of Some Biological and Pharmaceutical Compounds

    , M.Sc. Thesis Sharif University of Technology Asadian, Elham (Author) ; Shahrokhian, Saeed (Supervisor)
    There are high attractions in the development of conducting polymer (CP) coatings to improve the electrochemical properties and biocompatibility of electrodes in the area of biosensors. In the first part of this thesis, a new type of modified electrodes, constructing multi-walled carbon nanotubes (MWCNTs) and polypyrrole is prepared in a layer-by-layer process. In this procedure, the glassy carbon electrode is casted first by a drop suspension of MWCNTs, leading to formation a thin film on its surface. In the second step, electrochemical polymerization of pyrrole in the presence of tiron (used as doping anion) is performed on the surface of the MWCNTs pre-coated electrode. The modification... 

    Investigation of Electrocatalytic Activity of Metal-based Nanocomposites in the Reaction of Carbon Dioxide Reduction

    , M.Sc. Thesis Sharif University of Technology Hatami, Homayoun (Author) ; Bastani, Darioush (Supervisor) ; Taherinia, Davood (Supervisor)
    Emissions of carbon dioxide (CO2) from fossil fuels are a potential issue for the global climate. One way to meet this challenge is to electrochemically convert CO2 molecules to reduced carbon species such as formates, alcohols, hydrocarbons, etc., which is a difficult process due to the poor kinetics of CO2 reduction. Therefore, the use of catalysts, while preventing undesirable side reactions, can also play an important role in reducing CO2. In this study, a two-step synthesis of CuS (1, 5, 12, 24 hr) @ Cu-MOF has been reported as an advanced electrocatalyst for CO2 reduction in neutral pH environments. Bismuth has been used to improve the electrocatalytic properties of the samples. Bi-CuS... 

    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)
    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... 

    The effect of layer number on the nanostructural ternary mixed oxide containing Ti, Ru and Ir on titanium

    , Article Advanced Materials Research ; Vol. 829 , 2014 , pp. 638-642 Goudarzi, M ; Ghorbani, M ; Sharif University of Technology
    Titanium anodes coated with noble metal oxides are widely used in chlorate industry. In fact, these anodes are dimensionally stable. In this article, the electrochemical characteristics of the ternary oxide coating created by sol-gel on titanium, which consisted of Ti, Ru and Ir, were investigated in the number of different layers. The electrochemical properties of anodes, morphology of samples, and phase analysis were investigated respectively by cyclic voltammetry and polarization measurements, Field Emission Scanning Electron Microscope (FESEM) and XRD. The result indicated that the application of the more layer number increases the rate of chlorine evolution. Also, The morphology of the... 

    Electrochemical synthesis of reduced graphene oxide/TiO2 nanotubes/Ti for high-performance supercapacitors

    , Article Ionics ; Volume 21, Issue 2 , 2014 , Pages 525-531 ; ISSN: 09477047 Gobal, F ; Faraji, M ; Sharif University of Technology
    RGO/TiO2NTs/Ti electrodes with high surface area and good capacitive characteristics were prepared by simple electrochemical reduction of graphene oxide (GO) onto the previously formed TiO2 nanotubes. Microstructure studies show that reduced graphene oxide (RGO) having high surface area has been deposited onto the TiO2NT arrays. The electrochemical capacitive behaviors of the obtained electrodes were investigated by cyclic voltammetry (CV), galvanostatic charge–discharge studies, and electrochemical impedance spectroscopy (EIS) in 1 M H2SO4 solution. The electrochemical data demonstrated that the electrodes displayed specific capacitance of 410 F g−1 at the current density of 50 A g−1 and... 

    Rapid and simultaneous determination of tetracycline and cefixime antibiotics by mean of gold nanoparticles-screen printed gold electrode and chemometrics tools

    , Article Measurement: Journal of the International Measurement Confederation ; Vol. 47, Issue. 1 , 2014 , pp. 145-149 ; ISSN: 02632241 Asadollahi-Baboli, M ; Mani-Varnosfaderani, A ; Sharif University of Technology
    The screen-printed gold electrode (SPGE) modified with the formation of self-assembly monolayer (SAM) of cysteine (Cys) on gold-nanoparticles (Au nano) was utilized for rapid and simultaneous determination of tetracycline and cefixime antibiotics by square wave voltammetry (SWV). Electrochemical investigation and characterization of the modified electrode was achieved using cyclic voltammetry (CV) and scanning electron microscopy (SEM). A principal component artificial neural network (PCANN) with three layer back-propagation network was utilized for the analysis of the voltammogram data. It is possible to simultaneously determine the tetracycline and cefixime concentrations in the ranges of... 

    Preparation and electrochemical performances of nanoporous/cracked cobalt oxide layer for supercapacitors

    , Article Applied Physics A: Materials Science and Processing ; Vol. 117, issue. 4 , 2014 , pp. 2087-2094 ; ISSN: 09478396 Gobal, F ; Faraji, M ; Sharif University of Technology
    Nanoporous/cracked structures of cobalt oxide (Co3O4) electrodes were successfully fabricated by electroplating of zinc–cobalt onto previously formed TiO2 nanotubes by anodizing of titanium, leaching of zinc in a concentrated alkaline solution and followed by drying and annealing at 400 °C. The structure and morphology of the obtained Co3O4 electrodes were characterized by X-ray diffraction, EDX analysis and scanning electron microscopy. The results showed that the obtained Co3O4 electrodes were composed of the nanoporous/cracked structures with an average pore size of about 100 nm. The electrochemical capacitive behaviors of the nanoporous Co3O4 electrodes were investigated by cyclic... 

    Synthesis and electrochemical characterization of sol-gel-derived RuO 2/carbon nanotube composites

    , Article Journal of Solid State Electrochemistry ; Vol. 18, Issue 4 , April , 2014 , pp. 993-1003 ; Online ISSN: 1433-0768 Kahram, M ; Asnavandi, M ; Dolati, A ; Sharif University of Technology
    Ruthenium oxide was coated on multiwalled carbon nanotubes (MWCNTs) to obtain nanocomposite electrode which has a good response to the pH. To synthesize this electrode, gold and cobalt were coated on a stainless steel 304 substrates, respectively, and then, vertically aligned carbon nanotubes were grown on the prepared substrates by chemical vapor deposition. Gold reduced activity of the stainless steel, while cobalt served as a catalyst for growth of the carbon nanotube. Ruthenium oxide was then coated on MWCNTs via sol-gel method. At last, different techniques were used to characterize the properties of synthesized electrode including scanning electron microscopy (SEM), transmission... 

    Pd-Au nanoparticle decorated carbon nanotube as a sensing layer on the surface of glassy carbon electrode for electrochemical determination of ceftazidime

    , Article Materials Science and Engineering C ; Vol. 34, issue. 1 , 2014 , pp. 318-325 ; ISSN: 09284931 Shahrokhian, S ; Salimian, R ; Rastgar, S ; Sharif University of Technology
    A simple electrodeposition method is employed to construct a thin film modifier of palladium-gold nanoparticles (Pd-AuNPs) decorated multi-walled carbon nanotube (MWCNT) on the surface of glassy carbon electrode (GCE). Morphology and property of Pd-AuNPs-MWCNT have been examined by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Electrochemical performance of Pd-AuNPs-MWCNT/GCE for detection of ceftazidime (CFZ) has been investigated by cyclic voltammetry (CV). This nanostructured film modified electrode effectively exhibited enhanced properties for detection of ceftazidime (CFZ). The effects of various experimental variables such as, the amount of casted MWCNT,... 

    MnO2/ordered mesoporous carbon nanocomposite for electrochemical supercapacitor

    , Article Journal of Solid State Electrochemistry ; Vol. 18, issue. 4 , 2014 , pp. 1117-1125 Kiani, M. A ; Khani, H ; Mohammadi, N ; Sharif University of Technology
    The preparation of composite manganese dioxide (MnO2) nanoparticles in an ordered mesoporous carbon (CMK-3) matrix and its use for constructing a new wide-potential-window supercapacitor is reported. CMK-3 is prepared using mesoporous silica as a hard template and sucrose as carbon source. The different ratios of MnO2/CMK-3 composite is synthesized by impregnating CMK-3 with a Mn(NO3)2·4H 2O solution followed by annealing in nitrogen. Physical properties, morphology, and specific surface area were characterized by X-ray diffraction, transmission electron microscopy, and nitrogen sorption measurements, respectively. The electrochemical properties of the composite were studied by cyclic... 

    Advanced gel polymer electrolyte for lithium-ion polymer batteries

    , Article ASME 2013 7th Int. Conf. on Energy Sustainability Collocated with the ASME 2013 Heat Transfer Summer Conf. and the ASME 2013 11th Int. Conf. on Fuel Cell Science, Engineering and Technology ; July , 2013 ; 9780791855515 (ISBN) Zhang, R ; Hashemi, N ; Ashuri, M ; Montazami, R ; Advanced Energy Systems Division, Solar Energy Division ; Sharif University of Technology
    We report improved performance of Li-ion polymer batteries through advanced gel polymer electrolytes (GPEs). Compared to solid and liquid electrolytes, GPEs are advantageous as they can be fabricated in different shapes and geometries; also ionic properties are significantly superior to that of solid and liquid electrolytes. We have synthetized GPE in form of membranes by trapping ethylene carbonate and propylene carbonate in a composite of polyvinylidene fluoride and N-methylpyrrolidinore. By applying phase-transfer method, we synthetized membranes with micro-pores, which led to higher ionic conductivity. The proposed membrane is to be modified further to have higher capacity, stronger... 

    Fabrication of nanoporous nickel oxide by de-zincification of Zn-Ni/(TiO2-nanotubes) for use in electrochemical supercapacitors

    , Article Electrochimica Acta ; Volume 100 , 2013 , Pages 133-139 ; 00134686 (ISSN) Gobal, F ; Faraji, M ; Sharif University of Technology
    NiO-ZnO/TiO2NTs electrodes were synthesized by the electrodeposition of Zn-Ni onto TiO2 nanotubes, dealloying in a concentrated alkaline solution and finally calcination of the resulting Zn(OH)2-Ni(OH)2/TiO2NTs at 300 C. Morphology of the electrodeposited nanostructures was studied using scanning electron microscopy (SEM) while their electrochemical characterizations were carried out using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge/discharge procedures. The SEM analysis revealed the nanoporous/cracked structures of the NiO-ZnO/TiO2NTs obtained at the electroplating time of 20 min. The EIS studies showed that nanoporous/cracked structures of... 

    Zeolite encapsulated Ni(II)-Schiff-base complex: A novel size-selective electro-catalyst for the determination of the purity of stevioside

    , Article Talanta ; Volume 108 , April , 2013 , Pages 19-29 ; 00399140 (ISSN) Rashvand Avei, M ; Jafarian, M ; Etezadi, S ; Gobal, F ; Khakali, M ; Rayati, S ; Ghasem Mahjani, M ; Sharif University of Technology
    Ship-in-a-bottle complex of nickel(II) containing the ligand N,N′-bis(2,4-dihydroxyacetophenone)-2,2-dimethylpropandiimine (H 2{salnptn(4-OH)2}) has been synthesized in zeolite Y. The characteristics of the encapsulated complex are identified by the methods of EDX, SEM, XRD, FT-IR and cyclic voltammetry. A catalytic effect in the electrochemical oxidation of glucose, fructose and sucrose, and a blocking effect in stevioside oxidation are demonstrated on the Ni II{salnptn(4-OH)2}-Y/CPE. The effects of some parameters, such as potential scan rate and concentration of carbohydrates are investigated. The rate constants for the catalytic reaction (k′) of carbohydrates are also obtained. The... 

    Construction of a modified carbon paste electrode based on TiO2 nanoparticles for the determination of gallic acid

    , Article Journal of Solid State Electrochemistry ; Volume 17, Issue 1 , 2013 , Pages 157-165 ; 14328488 (ISSN) Tashkhourian, J ; Nami Ana, S. F ; Hashemnia, S ; Hormozi Nezhad, M. R ; Sharif University of Technology
    A modified carbon paste electrode was prepared by incorporating the TiO2 nanoparticles in the carbon paste matrix. The electrochemical behavior of gallic acid (GA) is investigated on the surface of the electrode using cyclic voltammetry and differential pulse voltammetry. The surface morphology of the prepared electrode was characterized using the scanning electron microscopy. The results indicate that the electrochemical response of GA is improved significantly at the modified electrode compared with the unmodified electrode. Furthermore, the capabilities of electron transfer on these two electrodes were also investigated by electrochemical impedance spectroscopy. Under the optimized...