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    Synthesis and Electrochemical Evaluation of Graphene-Ni/Cu/Zn Nanocomposite Coating Modified by Pt/Ru Nanoparticles

    , Ph.D. Dissertation Sharif University of Technology Yaghoubinezhad, Yadollah (Author) ; Afshar, Abdollah (Supervisor)
    In this research,Graphene Oxide nanoplatelets (GO) were synthesized by chemically modified Hummer's method.After the GO nanosheets electrochemically reduced to graphene, nanoparticles imposed to this thin film.This optimized nanostructure coating was utilized for investigating the Hydrogen Evolution Reaction (HER) over the copper substrate. In order to optimize the kinetic of electrodeposition and reduction, diverse electrochemical approaches such as cyclic voltammetry, chronoamperometic and potentiometric as well as pulse electrodeposition methods were employed. Electrochemical procedures were aligned by Design of Experiment (DOE) ... 

    Synthesis, Characterization and Photoelectrochemical Properties of BiVO4 Porous Thin Films

    , M.Sc. Thesis Sharif University of Technology Rasouli Ardalani, Abolfazl (Author) ; Moshfegh, Alireza (Supervisor) ; Zirak, Mohammad (Co-Supervisor)
    Synthesis, characterization and photoelectrocatalytic performance evaluation of worm-like BiVO4 porous films have been conducted in this research. An in situ combustion approach was employed to prepare BiVO4 nanolayers on glass and ITO/glass by using drop casting, spin coating, dip coating and pulsed spray pyrolysis deposition techniques. The precursor solution of vanadium and bismuth include ~0.0233g ammonium metavanadate (NH4VO3) and ~0.0970g bismuth (III) nitrate pentahydrate (Bi(NO3)3.5H2O) in 2.5 mL ethylene glycol. Different deposition parameters were investigated for each of the aforementioned deposition techniques to obtain a uniformly-deposited BiVO4 nanolayer with high adhesion to... 

    Carbon Dioxide Recovery From Flue Gases by Means of Appropriate Absorbents

    , M.Sc. Thesis Sharif University of Technology Lotfi Varnoosfaderani, Mohammad (Author) ; Molaei Dehkordi, Asghar (Supervisor)
    Due to the increasing concentration of greenhouse gases in the earth's atmosphere and their destructive consequences, many scientists and researchers have turned to preventing the emission of greenhouse gases, such as carbon dioxide. One of the primary sources of carbon dioxide emissions is flue gases. Carbon dioxide is one of the most important greenhouse gases, the release of which causes global temperature increase and climate change. One of the options for reducing carbon dioxide emissions from gas streams is using reactive amine solvents, considered the most critical technologies for carbon dioxide removal. The only commercially available carbon dioxide separation method is absorption... 

    Simultaneous electrodeposition of reduced graphene oxide/ag nanoparticles as a sensitive layer for voltammetric determination of tinidazole

    , Article Nano ; Volume 12, Issue 6 , 2017 ; 17932920 (ISSN) Shahrokhian, S ; Navabi, M ; Mohammadi, R ; Sharif University of Technology
    World Scientific Publishing Co. Pte Ltd  2017
    A stable composite film of silver nanoparticles (Ag NPs) decorated on reduced graphene oxide is prepared by a two-step simple procedure. The surface morphology of the modified electrode is characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques. The electrochemical behavior of tinidazole (TNZ) on the surface of the modified electrode is investigated by linear sweep voltammetry and electrochemical impedance spectroscopy. The prepared composite electrode acts as a highly sensitive platform for the voltammetric determination of TNZ, leading to a significant increase in the reduction peak current of TNZ. The effects of experimental parameters such as the... 

    Capturing Co2 of the Atmosphere by Molten Carbonates and Transforming to Carbon Nanofiber

    , M.Sc. Thesis Sharif University of Technology Zarei, Mohammad Mahdi (Author) ; Moosavi, Ali (Supervisor) ; Nouri Borujerdi, Ali (Supervisor)
    Capturing the atmospheric CO2 and turning it into value added products is a topic that has been extensively studied in recent years. One of the methods through which CO2 is valorized is via converting it into carbon nanofiber, CNFs. CNFs can be an important material in future human activities due to its valuable properties such as wide range of electrical conductivity, their superior flexibility and strength, But it is currently obstructed in use due to the high cost of manufacturing and the complexity of the synthesis. Furthermore, in today's world, human life is heavily influenced by greenhouse gases, and avoiding emitting gases like CO2, is almost infeasible. This thesis provides an... 

    Electrodeposited multi-walled carbon nanotubes on Ag-loaded TiO2 nanotubes/Ti plates as a new photocatalyst for dye degradation

    , Article RSC Advances ; Volume 5, Issue 56 , 2015 , Pages 44840-44846 ; 20462069 (ISSN) Mohaghegh, N ; Faraji, M ; Gobal, F ; Gholami, M. R ; Sharif University of Technology
    Royal Society of Chemistry  2015
    MWCNTs/Ag/TiO2NTs plates were synthesized via electrochemical reduction of functionalized multiwalled carbon nanotubes (MWCNTs) on Ag/TiO2NTs. The loading of silver nanoparticles was carried out by electroless reduction of Ag1+ onto TiO2 nanotubes previously formed by anodizing titanium. The SEM analysis revealed that MWCNTs were loaded significantly on the as-prepared Ag/TiO2NTs, where nanoparticles of Ag had grown on the walls of TiO2NTs. The photocatalytic activity of the synthesized plates was evaluated by the photodegradation of Methyl Orange (MO) dye under UV light irradiation. The results indicated that the MWCNTs/Ag/TiO2NTs demonstrated improved efficiency for MO photodegradation in... 

    Ag/TiO2-nanotube plates coated with reduced graphene oxide as photocatalysts

    , Article Surface and Coatings Technology ; Volume 288 , 2016 , Pages 144-150 ; 02578972 (ISSN) Faraji, M ; Mohaghegh, N ; Sharif University of Technology
    RGO/Ag/TiO2-nanotubes/Ti plates with high photocatalytic activity were fabricated via electrochemical reduction of graphene oxide on Ag/TiO2-nanotubes. The loading of silver nanoparticles was carried out by electroless reduction of Ag1+ onto TiO2 nanotubes previously formed by anodizing titanium. Microstructure studies show that reduced graphene oxide (RGO) layers having high surface area have been deposited on the as-prepared Ag/TiO2-nanotubes, where nanoparticles of Ag had grown on the walls of TiO2-nanotubes. The results of photocatalytic experiments demonstrate that the RGO/Ag/TiO2-nanotubes/Ti plate exhibits significantly enhanced photocatalytic activity for the photocatalytic... 

    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... 

    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... 

    Au-Pd bimetallic nanoparticle electrodes for direct electroreduction of hexavalent chromium complexes

    , Article Australian Journal of Chemistry ; Volume 69, Issue 4 , 2016 , Pages 423-430 ; 00049425 (ISSN) Moakhar, R. S ; Hariri, M. B ; Kushwaha, A ; Dolati, A ; Ghorbani, M ; Goh, G. K. L ; Sharif University of Technology
    CSIRO  2016
    This paper reports a simple, low-cost, and effective electrochemical technique for sensing and reducing CrVI based on a Au-Pd bimetallic nanoparticle (BNP)-decorated indium tin oxide (ITO) conducting glass electrode. It was observed that the Au-Pd BNP-decorated ITO electrode could significantly boost the electrochemical reduction of CrVI when compared with either Au nanoparticle- or Pd nanoparticle-decorated ITO electrodes. These BNP-decorated electrodes exhibited a wide linear concentration range of 0.001-100 μM, a very low detection limit (signal-to-noise ratio = 3) of 0.3 nM, and a high sensitivity of 1.701 μA μM-1. From electrochemical impedance spectroscopy, it was revealed that this... 

    Specific picomolar detection of a breast cancer biomarker her-2/neu protein in serum: electrocatalytically amplified electroanalysis by the aptamer/peg-modified electrode

    , Article ChemElectroChem ; Volume 4, Issue 4 , 2017 , Pages 872-879 ; 21960216 (ISSN) Salimian, R ; Kékedy Nagy, L ; Ferapontova, E. E ; Sharif University of Technology
    Wiley-VCH Verlag  2017
    Specific and sensitive electroanalysis of blood-circulating protein cancer biomarkers is often complicated by interference from serum proteins nonspecifically adsorbing at the biosensing interface and masking specific reactions of interest. Here, we have developed an electrocatalytically amplified assay for specific and sensitive analysis of human epidermal growth factor receptor-2 (HER-2/neu, a protein cancer biomarker over-expressed in breast cancers) that allows us to avoid both the interference from bovine serum albumin (BSA) and electrocatalytic amplification of the signal stemming from the specific aptamer−HER-2/neu binding. A HER-2/neu-specific thiolated aptamer sequence was... 

    A high performance supercapacitor based on graphene/polypyrrole/Cu2O-Cu(OH)2 ternary nanocomposite coated on nickel foam

    , Article Journal of Physical Chemistry C ; Volume 121, Issue 12 , 2017 , Pages 6508-6519 ; 19327447 (ISSN) Asen, P ; Shahrokhian, S ; Sharif University of Technology
    A simple and low-cost electrochemical deposition method is used to prepare reduced graphene oxide/polypyrrole/Cu2O-Cu(OH)2 (RGO/PPy/Cu2O-Cu(OH)2) ternary nanocomposites as the electrode material for supercapacitor application. First, graphene oxide-polypyrrole (GO/PPy) nanocomposite is electrochemically synthesized on Ni foam by electro-oxidation of pyrrole monomer in an aqueous solution containing GO and Tiron. Subsequently, the GO/PPy film is converted to the corresponding reduced form (RGO/PPy) by an effective and eco-friendly electrochemical reduction method. Then, a thin layer of Cu2O-Cu(OH)2 is formed on RGO/PPy film by chronoamperometry. The RGO/PPy/Cu2O-Cu(OH)2 nanocomposite is... 

    Ultrasensitive detection of cancer biomarkers using conducting polymer/electrochemically reduced graphene oxide-based biosensor: Application toward BRCA1 sensing

    , Article Sensors and Actuators, B: Chemical ; Volume 266 , 2018 , Pages 160-169 ; 09254005 (ISSN) Shahrokhian, S ; Salimian, R ; Sharif University of Technology
    Elsevier B.V  2018
    Breast Cancer (BRCA) is the most common threat in women worldwide. Increasing death rate of diagnosed cases is the main leading cause of designing specific genosensors for BRCA − related cancer detection. In the present study, an ultrasensitive label − free electrochemical DNA (E − DNA) sensor based on conducting polymer/reduced graphene − oxide platform has been developed for the detection of BRCA1 gene. An electrochemical method was applied as a simple and controllable technique for the electrochemical reduction of graphene oxide and also, electro − polymerization of pyrrole − 3 − carboxylic acid monomer. The results of the present work show that the polymer − coated reduced graphene −... 

    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... 

    Electrochemical deposition of gold nanoparticles on carbon nanotube coated glassy carbon electrode for the improved sensing of tinidazole

    , Article Electrochimica Acta ; Volume 78 , September , 2012 , Pages 422-429 ; 00134686 (ISSN) Shahrokhian, S ; Rastgar, S ; Sharif University of Technology
    The electrochemical reduction of tinidazole (TNZ) is studied on gold-nanoparticle/carbon-nanotubes (AuNP/CNT) modified glassy carbon electrodes using the linear sweep voltammetry. An electrochemical procedure was used for the deposition of gold nanoparticles onto the carbon nanotube film pre-cast on a glassy carbon electrode surface. The resulting nanoparticles were characterized by scanning electron microscopy and cyclic voltammetry. The effect of the electrodeposition conditions, e.g., salt concentration and deposition time on the response of the electrode was studied. Also, the effect of experimental parameters, e.g., potential and time of accumulation, pH of the buffered solutions and... 

    Nanocomposite with promoted electrocatalytic behavior based on bimetallic pd-ni nanoparticles, manganese dioxide, and reduced graphene oxide for efficient electrooxidation of ethanol

    , Article Journal of Physical Chemistry C ; Volume 122, Issue 18 , 2018 , Pages 9783-9794 ; 19327447 (ISSN) Rezaee, S ; Shahrokhian, S ; Amini, M. K ; Sharif University of Technology
    American Chemical Society  2018
    In this work, a nanocomposite containing manganese dioxide (MnO2) modified reduced graphene oxide (rGO) supported bimetallic palladium-nickel (Pd-Ni) catalyst is prepared by electrodeposition method. The nanocomposite modifier film is prepared by forming a thin layer of graphene oxide (GO) via drop-casting of GO nanosheet dispersion on glassy carbon electrode (GCE), followed by electrochemical reduction of the film to provide rGO/GCE. Then, a two-step potential procedure is applied to deposit MnO2 nanoparticles on rGO/GCE. At the optimum deposition conditions, MnO2 nanoparticles with a thickness of 30-50 nm homogeneously covered the rGO surface (MnO2/rGO/GCE). Finally, the bimetallic Pd-Ni... 

    Grafting the sol-gel based sorbents by diazonium salts: A novel approach toward unbreakable capillary microextraction

    , Article Journal of Chromatography A ; Volume 1318 , November , 2013 , Pages 58-64 ; 00219673 (ISSN) Bagheri, H ; Bayat, P ; Piri Moghadam, H ; Sharif University of Technology
    The present work deals with a novel approach for grafting a sol-gel based sorbent, using diazonium salts for preparation of an unbreakable capillary microextraction (CME) device in on-line combination with high performance liquid chromatography (HPLC). The use of diazonium salts modifier allowed all types of metallic and non-metallic substrates to be used without any limitation. Substrates including copper, brass, stainless steel and polytetrafluoroethylene (PTFE) were chosen to be functionalized by chemical or electrochemical reduction of 4-amino phenyl acetic acid. Then, 3-(trimethoxysilyl)propylamine (3TMSPA) was selected as the precursor and the only reagent for preparation of the... 

    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...