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    Hybrid supercapacitors constructed from double-shelled cobalt-zinc sulfide/copper oxide nanoarrays and ferrous sulfide/graphene oxide nanostructures

    , Article Journal of Colloid and Interface Science ; Volume 585 , 2021 , Pages 750-763 ; 00219797 (ISSN) Shahi, M ; Hekmat, F ; Shahrokhian, S ; Sharif University of Technology
    Academic Press Inc  2021
    Evolution of renewable energies in the era of the modernized world has been strongly tied up to the incessant development of high-performance energy storage systems benefiting from both high energy and power densities. In the present work, binder-free positive electrodes are fabricated via a facile electrochemical deposition route in which copper oxide nanorods (CuO NRs) directly grown onto the copper foam (CF) are decorated with bimetallic cobalt-zinc sulfide nanoarrays (Co-Zn-S NAs). The fabricated Co-Zn-S@CuO-CFs represent promising specific capacity of 317.03 C.g−1 at 1.76 A.g−1, along with superior cyclic stability (113% retention after 4500 cycles). Negative electrodes were further... 

    DFT calculations on retro-ene reactions part I: Allyl n-butyl sulfide pyrolysis in the gas phase

    , Article Journal of Chemical Research ; Issue 9 , 2004 , Pages 585-588 ; 03082342 (ISSN) Izadyar, M ; Jahangir, A. H ; Gholami, M. R ; Sharif University of Technology
    Scientific Reviews Ltd  2004
    The mechanism and kinetic aspects of the retro-ene reaction of allyl n-butyl sulfide and its deuterated derivative were studied using four different types of density functional theory (DFT) methods with eight different levels of the basis sets. Vibrational frequency analysis confirmed that the stationary points include the transition state (TS) structure with only one imaginary frequency. Mechanistic studies on the retro-ene process rejected the step-wise mechanism and confirmed that the reaction proceeds through a six-centered cyclic transition state. Theoretical calculations show that propene elimination from the reactant can occur through an asynchronous concerted mechanism. A primary... 

    Enhancement of Mn luminescence in ZnS:Mn multi-quantum-well structures

    , Article Applied Physics Letters ; Volume 83, Issue 22 , 2003 , Pages 4616-4618 ; 00036951 (ISSN) Taghavinia, N ; Makino, H ; Yao, T ; Sharif University of Technology
    The efficiency of Mn luminescence is enhanced in low-thickness ZnS:Mn layers. While various hypotheses can be considered to explain the phenomenon, it seems more reasonable to consider the luminescence enhancement effect a result of the formation of dot-like regions with higher local Mn concentration  

    Gas-phase kinetics and mechanism of diallyl sulfide thermal decomposition

    , Article Journal of Physical Organic Chemistry ; Volume 16, Issue 3 , 2003 , Pages 153-157 ; 08943230 (ISSN) Gholami, M. R ; Izadyar, M ; Sharif University of Technology
    The gas-phase kinetics of diallyl sulfide pyrolysis were studied experimentally and theoretically in a static system over the temperature range 433-463 K and a total pressure of 80 Torr in a glass vessel with the free radical inhibitor cyclohexene. The experimental results show that this reaction is homogeneous, unimolecular and follows a first-order rate law. Theoretical studies at the B3LYP/6-31G* computational level indicate that the elimination reaction proceeds through a six-centered cyclic transition state and the reaction mechanism is concerted and non-synchronous. Copyright © 2003 John Wiley & Sons, Ltd  

    Preparation and Properties of Zinc Sulfide Nanoparticles Doped with Manganese

    , M.Sc. Thesis Sharif University of Technology Raeesi, Padideh (Author) ; Mohammadi Boghaei, Davar (Supervisor)
    The optical properties of semiconductor nanoparticles are dependent on their size. Then, the important problem in synthesized semiconductor nanoparticles is controllable of their size. In this research ZnS nanoparticles were synthesized by hydrothermal method and taguchi design of experiments and study on effect of solvent, reaction temperature and molar precursor ratio on band gap and particle size of ZnS . The UV-Vis spectrum was carried out for measurement of band gap and the size of nanoparticles by using the effective mass approximation. The X-ray diffraction patterns exhibited a cubic zinc blende structure for the nanoparticles. The ZnS:Mn +2 nanoparticles werw synthesized. With... 

    Hot Workability of a Free-cutting Steel with Severe Sulfur Segregation During Continuous Casting

    , M.Sc. Thesis Sharif University of Technology Naghdy, Soroosh (Author) ; Akbarzadeh, Abbas (Supervisor)
    Splitting in ingot cast structures and transverse cracks in continuous cast structures are the main problems of hot rolling of low carbon resulfurized free-cutting (LCRF) steels. Presence of high volume fraction of manganese sulfide inclusions in cast structure increases the risk of alligatoring in hot rolling. Because of high sulfur content of these steels and probability of formation of low melting point phases, minimum level of manganese and maximum level of copper and tin is necessary. Morphology of manganese sulfide is another important factor in hot forming of these steels, which can be controlled by level of deoxidation in steel making. In fact, MnS2 is present in fully killed... 

    Kinetic of Zinc Sulfide Roasting of

    , M.Sc. Thesis Sharif University of Technology Marzoughi, Omid (Author) ; Halali, Mohammad (Supervisor)
    In this study, the effect of two main parameters, time and temperature, were investigated in the roasting process of zinc sulfide of Bafgh’s mine, and kinetics and the mechanism of the roasting reaction were examined, too. The oxidation process was performed in a muffle furnace in the presence of the oxygen of air atmosphere. The raw powder material (with the particle size of 74-250 micron) was poured in Alumina crucibles. The roasting process was run in eight temperatures of 650, 700, 750, 800, 850, 900, 950 and 1000 ◦C. Oxidation percent was calculated in six times of 5, 10, 15, 30, 45 and 60 minutes. The experiments were designed in a way that the effect of each parameter could be... 

    Investigating the Electrochemical Behavior of Co-Zn Sulfides and Hydroxides on Copper Oxide Nano-structures Grown on Copper Foam for Application in Electrochemical Supercapacitors

    , M.Sc. Thesis Sharif University of Technology Shahi, Mahdiyeh (Author) ; Shahrokhian, Saeed (Supervisor)
    In the first part, Co-Zn hydroxides were deposited onto CuO nanorods, and their electrochemical behavior and capacitive performance were investigated. To this end, Cu(OH)2 nanorods were grown on copper foam through a chemical process. Then, Cu(OH)2 were converted to CuO nanorods via a calcination process. In the next step, Co-Zn-OH sheets were electrodeposited on CuO nanorods. FE-SEM images of the prepared electrodes demonstrate the formation of Co-Zn-OH nanosheets onto CuO nanorods. Crucial electrochemical evaluations such as cyclic voltammetry (CV), galvanostatic charge/discharge (GCD), rate capability, and electrochemical impedance spectroscopy (EIS) were carried out. According to the... 

    Molybdenum oxo-peroxo complex: A very fast catalyst for oxidation and reduction of sulfur-based compounds

    , Article Catalysis Communications ; Volume 23 , June , 2012 , Pages 14-19 ; 15667367 (ISSN) Bagherzadeh, M ; Haghdoost, M. M ; Amini, M ; Derakhshandeh, P. G ; Sharif University of Technology
    We have evaluated the catalytic activity of a molybdenum(VI) oxo-peroxo complex through the oxidation and reduction of sulfur-based compounds. Arylalkyl, diaryl and dialkyl sulfides are selectively oxidized to corresponding sulfoxides, with tert-butyl hydroperoxide (TBHP), in the presence of MoO(O 2)(phox) 2 complex as catalyst. This molybdenum complex was also found to be an efficient catalyst for the deoxygenation of sulfoxides to sulfides with PPh 3 in excellent yields and chemoselectivity  

    Electrochemical determination of CdS band edges and semiconducting parameters

    , Article Bulletin of the Chemical Society of Japan ; Volume 88, Issue 6 , February , 2015 , Pages 814-820 ; 00092673 (ISSN) Miandari, S ; Jafarian, M ; Mahjani, M. G ; Gobal, F ; Heidaripour, A ; Sharif University of Technology
    Chemical Society of Japan  2015
    Cadmium sulfide (CdS) thin film was electrodeposited on indium tin oxide (ITO) by chronoamperometry. The SEM images showed that hexagonal sheets of CdS deposited on the ITO surface. The X-ray diffraction (XRD) analysis confirmed this structure for CdS crystals and the average of crystalline size and the lattice constant parameters are approximately 39.54 and a = 0.4136, c = 0.6696 nm respectively. Photo-electrochemical investigations were performed by cyclic voltammetry (CV), linear sweep voltammetry (LSV), and electrochemical impedance spectroscopy (EIS) techniques. CdS band edges and density of states (DOS) were determined by CV technique. The band gap energy (Ebg) was measured... 

    How CdS nanoparticles can influence TiO2 nanotube arrays in solar energy applications?

    , Article Applied Catalysis B: Environmental ; Volume 162 , January , 2015 , Pages 210-216 ; 09263373 (ISSN) Qorbani, M ; Naseri, N ; Moradlou, O ; Azimirad, R ; Moshfegh, A. Z ; Sharif University of Technology
    Elsevier  2015
    In this study, titanium dioxide (TiO2) nanotube array (TNA) films are fabricated via anodization of titanium (Ti) sheet. After annealing, the films consisted of well ordered, vertically oriented TNAs of 125±6nm diameter, 38±3nm wall thickness, and 2.9±0.3μm in length. Cadmium sulfide (CdS) nanoparticles are deposited on the synthesized TNAs by sequential-chemical bath deposition (S-CBD) method with different immersion cycle (n) to produce heterogeneous TNA/CdS-n (n=10, 20 and 30) nanostructures. UV-visible absorption spectra of the samples revealed that the absorption edge of CdS modified TNAs was shifted to a higher wavelength with respect to the pure TNAs indicating band gap reduction of... 

    Immobilized tungstate on magnetic poly(2-ammonium ethyl acrylamide): A high loaded heterogeneous catalyst for selective oxidation of sulfides using H2O2

    , Article Journal of Industrial and Engineering Chemistry ; Volume 44 , 2016 , Pages 73-81 ; 1226086X (ISSN) Zohreh, N ; Hosseini, S. H ; Pourjavadi, A ; Soleyman, R ; Bennett, C ; Sharif University of Technology
    Korean Society of Industrial Engineering Chemistry  2016
    A heterogeneous tungstate-based catalyst has been prepared for selective oxidation of sulfides to sulfoxides in the presence of 30% H2O2. The catalyst was prepared via immobilization of high amounts of WO4 2− onto the cross-linked poly(ammonium ethyl acrylamide) coated magnetic nanoparticles (MNP). FT-IR, TEM, TGA, VSM, XRD, EDX, and CHN analysis were used for characterization of catalyst. Variety of sulfides successfully converted to the related sulfoxides using 1 mol% of catalyst at room temperature in high yields. The catalyst was easily recovered and reused up to 6 times without loss of activity  

    New insight into H2S sensing mechanism of continuous SnO2-CuO bilayer thin film: A theoretical macroscopic approach

    , Article Journal of Physical Chemistry C ; Volume 120, Issue 14 , 2016 , Pages 7678-7684 ; 19327447 (ISSN) Boroun, Z ; Ghorbani, M ; Moosavi, A ; Mohammadpour, R ; Sharif University of Technology
    American Chemical Society  2016
    SnO2-CuO is one the most promising systems for detection of detrimental H2S gas. Although previous experimental research has suggested a sulfidation reaction to explain selectivity toward H2S, little is known about the origin of change of electrical response of this system by changing the H2S gas concentration. In this study the relation between sensing response of continuous SnO2-CuO bilayer thin film and H2S gas concentration is computed based on changeability of chemical composition of covellite CuxS. For this purpose, chemical activity of sulfur as a function of atomic fraction in covellite copper sulfide is estimated using Gibbs energies of formation and chemical thermodynamics. By... 

    Simple One-Step Fabrication of Semiconductive Lateral Heterostructures Using Bipolar Electrodeposition

    , Article Physica Status Solidi - Rapid Research Letters ; 2018 ; 18626254 (ISSN) Jamilpanah, L ; Azizmohseni, S ; Hosseini, S. A ; Hasheminejad, M ; Vesali, N ; Iraji Zad, A ; Pourfath, M ; Mohseni, S. M ; Sharif University of Technology
    Wiley-VCH Verlag  2018
    Unidirectional current flow is at the heart of modern electronics, which has been conceived by making p–n junctions or Schottky barriers between different kinds of materials. Within such elements, however, synthesis of thin film lateral heterostructures has so far remained challenging. Here, a one-step simple synthesis of p-type, n-type, and metallic lateral heterostructures using bipolar electrodeposition (BPE) technique is reported. Molybdenum oxides and sulfides with gradient of oxygen and sulfur are deposited at a metallic substrate. A lateral heterostructure is achieved with electrical properties that change from p- to n-type semiconductor and then to metal by moving in the plane of the... 

    Characterization of three-dimensional reduced graphene oxide/copper oxide heterostructures for hydrogen sulfide gas sensing application

    , Article Journal of Alloys and Compounds ; Volume 740 , 2018 , Pages 1024-1031 ; 09258388 (ISSN) Mirmotallebi, M ; Iraji zad, A ; Hosseini, Z. S ; Jokar, E ; Sharif University of Technology
    Elsevier Ltd  2018
    Three-dimensional reduced graphene oxide (3D-rGO) structures decorated with CuO particles (GCu) are synthesized through a simple and scalable method for detection of hydrogen sulfide (H2S) gas. For characterization and investigation of porous structure various techniques were employed. Decorated 3D structures demonstrated higher sensitivity and selectivity in comparison to pure structure. Optimized structure for sensing was obtained through introducing different amounts of CuO. The GCu heterostructures containing 35 μmol of CuO powder demonstrated reproducible response of about 30% to the concentration of 10 ppm at room temperature, while complete recovery was obtained through heating to 150... 

    Experimental Studies on the Application of Biosensors for Detection of Toxic Compounds

    , M.Sc. Thesis Sharif University of Technology Ghadiri, Mohammad (Author) ; Roosta Azad, Reza (Supervisor) ; Kariminia, Hamid Reza (Supervisor)
    In this project, quantification of sulfide ion was investigated based on peroxidase enzyme inhibition. The fungal peroxidase was obtained from the liquid culture of Coprinus cinereus NBRC 30628. Two different biosensing systems were suggested for sulfide ion measurement: (1) An amperometric inhibition peroxidase biosensor proposed for determination of sulfide by in situ bulk polymerization of acrylamide for immobilization of peroxidase on screen-printed carbon electrode. Measurements were performed using phosphate buffer solution as a supporting electrolyte in the presence of hydroquinone as a mediator. Identification method was based on reduction of generation current, caused by hydrolysis... 

    , M.Sc. Thesis Sharif University of Technology Rahmani, Atefeh (Author) ; Gholami, Mohammad Reza (Supervisor)
    Nanosized CdS coupled TiO2 nanocrystals were prepared by a microemulsion-mediated Hydrothermal method at relatively low temperatures. Modification of this nanocomposite with Tyrosine,Phenylalanine,Glysine and Glutamate ,especially Tyrosine resulted in enhanced photocatalytic degradation rate of Nitrobenzene( NB ) compared to using CdS-TiO2 under visible light irradiation. The prepared samples were characterized by BET,SEM, XRD, UV–Vis spectroscopy ,FTIR .It was found which have high surface area about 470 m2 g−1 and mesoporous character with the average pore diameter of 2.8 nm.The results showed this nanocomposite consisted of uniform anatase TiO2 with highly dispersed cubic phase CdS... 

    The Effect of Cadmium, Calcium and Zinc on Optoelectronic Properties of PbS Quantum Dots

    , M.Sc. Thesis Sharif University of Technology Mirfasih, Mohammad Hassan (Author) ; Simchi, Abdolreza (Supervisor)
    In recent years, much attention has been focused on quantum dot films due to their high amount of surface area and their size-dependant band-gap tenability. However, high surface area results in increase in energy traps in case of insufficient surface passivation. In this research, PbS colloidal quantum dots were synthesized via hot injection route having the size of 3 nm approximately. Then cationic doping with Zn, Ca and Cd and ligand exchange of long oleic acid with short organic mercaptopionic acid were done. Excitonic peak of these dots and photoluminescence peak appeard in wavelengths of 930 and 1100 nm respectively. Optimum film thickness was also determined as 300 nm. Quantum dot... 

    Synthesis and Characterization of ZnO Nanostructure, Modified by Graphene and CdS for PEC Application

    , M.Sc. Thesis Sharif University of Technology Nourmohammadi, Mohammad Amin (Author) ; Moshfegh, Alireza (Supervisor)
    In this project, the photoelectrochemical properties of ZnO nanostructures modified by CdS and Graphene was studied. Firs, titanium foil was cut into rectangular shape with 1cm width and 3 cm length, cleaned by rinsing in acetone and ethanol and annealed at 4000C for an hour. As a result, a thin layer of titanium oxide was formed on Ti sheet. Then a layer of grapheme oxide was deposited on substrate using Electrophoretic deposition (EPD). After that, ZnO nanostructure was deposited on the TiO2 substrate using Electropulsation (EP) with 20 consecutive pulse followed by 3 minutes Electrodeposition (ED). Using SEM analysis, the morphology of ZnO was determined to be nanopetals in which the... 

    Synthesis and Characterization of Tungsten (VI)Complex with Oxazine Ligand and its Catalytic Application in Oxidation of Sulfides to Sulfoxides

    , M.Sc. Thesis Sharif University of Technology Esmailpour Firoozsalary, Parvin (Author) ; Bagherzadeh, Mojtaba (Supervisor)
    In this study a novel oxo-diperoxo tungsten(VI) complex [WO(O2)2(phox)] was prepared by reaction of WO3 in H2O2 with oxazine-type ligand, 2-(2′-hydroxyphenyl)-5,6-dihydro-1,3-oxazine (Hphox). The complex was characterized by FTIR, 1H NMR and elemental analysis. The single-crystal X-ray diffraction studies revealed a seven coordinate tungsten center with a distorted octahedral geometry. The [WO(O2)2(phox)] complex was applied as a catalyst in efficient, and selective oxidation of sulfide to sulfoxide using 30% H2O2 or UHP as oxidants. This catalyst showed excellent catalytic activities and high selectivities in producing a variety of aryl and alkyl sulfoxides under mild conditions. To get...