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Al doped ZnO NanoStructures by Electrodeposition & Solvothermal for Dye Sensitized Solar Cells Application
, M.Sc. Thesis Sharif University of Technology ; Taghavinia, Nima (Supervisor)
Abstract
ZnO semiconductor has a wide band gap (3.3eV) and high electron mobility, making it a possible candidate for an effective structure-based Dye-sensitized solar cell (DSSC) semiconductor. Efficiency of DSSC based on ZnO is lower than TiO2 due to its low chemical satability. It is well known that the energy conversion efficiency of DSSC depends on the electron transport in the photoelectrode so in this investigation we fabricated high transport photoelectrode by doping Al in ZnO nanostructures. DSSC based on Al doped and undoped ZnO nanosheet synthesized by electrochemical deposition. Current density-voltage (J-V) characterizations indicate that Al-doping in ZnO crystal structure increases...
Modeling of platinum extraction from used reforming catalyst in iodine solutions
, Article ECS Transactions ; Volume 41, Issue 17 , 2012 , Pages 45-51 ; 19385862 (ISSN) ; 9781607683070 (ISBN) ; Baghallha, M ; Sharif University of Technology
Abstract
Platinum extraction from spent reforming catalysts in iodine solutions under atmospheric pressure and at temperatures up to 95°C was previously investigated in our group. In this system, platinum is oxidized from the spent catalyst with tri-iodide. In some of the experiments, it was observed that platinum extraction peaked and then decreased. This indicates that a precipitation reaction slowly occurs that removes the dissolved Pt ions from the solution. Power-law rate equation for the Pt extraction to PtI6 2- and the precipitation of the dissolved platinum to PtI 4(s) was implemented to model the experimental Pt extraction data. The activation energies for the platinum dissolution reaction...
Voltammetric behavior and determination of trace amounts of omeprazole using an edge-plane pyrolytic graphite electrode
, Article Iranian Journal of Pharmaceutical Research ; Volume 14, Issue 2 , Spring , 2015 , Pages 465-471 ; 17350328 (ISSN) ; Ghalkhani, M ; Bayat, M ; Ghorbani Bidkorbeh, F ; Sharif University of Technology
Iranian Journal of Pharmaceutical Research
2015
Abstract
The voltammetric performance of edge-plane pyrolytic graphite (EPG) electrode via adsorptive stripping voltammetry was investigated for study of the electrochemical behavior of omeprazole (OMZ) in aqueous solution. The results revealed that the oxidation of OMZ is an irreversible pH-dependent process that proceeds with the transfer of one electron and one proton in an adsorption-controlled mechanism. The determination conditions, such as the pH values of the supporting electrolyte, accumulation time and scan rate were optimized. Simplicity, high reproducibility and low detection limit (3 nM) of the electrode response as well as wide linear range (0.01 to 4.0 µM) can be stated as significant...
Reproducible electrochemical analysis of nanostructured Cu2O using a non-aqueous 3-methoxypropionitrile-based electrolyte
, Article Electrochemistry Communications ; Volume 86 , 2018 , Pages 1-5 ; 13882481 (ISSN) ; Iraji zad, A ; Mohammadpour, R ; Sharif University of Technology
Elsevier Inc
2018
Abstract
Cu2O is an attractive material in terms of semiconducting properties and is considered a leading candidate in all-oxide photovoltaics. Electrochemical analysis of Cu2O, including Mott-Schottky (MS) and impedance spectroscopy (IS), provides a wealth of data on charge carriers, Fermi level and interface properties. MS and IS are usually measured in aqueous solutions. However, Cu2O is easily reduced or oxidized to Cu or CuO in aqueous solutions, the layer peels off after the analysis and there is a small voltage window for the tests. In some cases, an anti-corrosive n-type barrier layer is employed on top of the bare Cu2O electrode to make the measurement possible, which could result in...
Smart chip for visual detection of bacteria using the electrochromic properties of polyaniline
, Article Analytical Chemistry ; Volume 91, Issue 23 , 2019 , Pages 14960-14966 ; 00032700 (ISSN) ; Farahmand Nejad, M. A ; Parolo, C ; Shahrokhian, S ; Merkoci, A ; Sharif University of Technology
American Chemical Society
2019
Abstract
Finding fast and reliable ways to detect pathogenic bacteria is crucial for addressing serious public health issues in clinical, environmental, and food settings. Here, we present a novel assay based on the conversion of an electrochemical signal into a more convenient optical readout for the visual detection of Escherichia coli. Electropolymerizing polyaniline (PANI) on an indium tin oxide screen-printed electrode (ITO SPE), we achieved not only the desired electrochromic behavior but also a convenient way to modify the electrode surface with antibodies (taking advantage of the many amine groups of PANI). Applying a constant potential to the PANI-modified ITO SPE induces a change in their...
Theoretical analysis of the performance of a model supercapacitor consisting of metal oxide nano-particles
, Article Journal of Solid State Electrochemistry ; Volume 11, Issue 8 , 2007 , Pages 1085-1092 ; 14328488 (ISSN) ; Gobal, F ; Sharif University of Technology
2007
Abstract
The factors influencing the electrochemical behaviour of a supercapacitor have been partly examined in this work. The effects of so-called intrinsic parameters, i.e. exchange current density, unit cell length and double layer (DL) capacitance; as well as the so-called application parameters, i.e. cell current, on the cell potential discharge time have been considered. The contributions of each type of capacitors, DL capacitor and faradaic supercapacitor under various states of operation and material have been analyzed, and the competing (compensating) effects of the two types of capacitors as regards to the discharge and power characteristics manifested by current-potential and energy-power...
Influence of coloring voltage and thickness on electrochromical properties of e-beam eaporated W O3 thin films
, Article Journal of the Electrochemical Society ; Volume 153, Issue 2 , 2006 , Pages E11-E16 ; 00134651 (ISSN) ; Akhavan, O ; Moshfegh, A. Z ; Sharif University of Technology
2006
Abstract
In this investigation, the effect of coloring voltage and thickness on optical and also electrochromical properties of W O3 thin films has been studied. The W O3 thin films were grown on glass and indium tin oxide coated conducting glass substrates by e-beam evaporation at different thicknesses of 200, 400, and 700 nm. Optical properties of the deposited samples were characterized in the ultraviolet-visible range (300-1100 nm). The optical bandgap energy of the W O3 was obtained in a range of 3.3-3.5 eV showing its increase by decreasing the film thickness. The refractive index of the W O3 films was measured around 2 in the visible range. Surface chemical states of the films were studied by...
A study on mutual interaction between atomistic and macroscopic phenomena during electrochemical processes using coupled finite difference - Kinetic Monte Carlo model: Application to potential step test in simple copper sulfate bath
, Article Journal of Electroanalytical Chemistry ; Volume 588, Issue 2 , 2006 , Pages 267-284 ; 15726657 (ISSN) ; Sharif University of Technology
Elsevier
2006
Abstract
A novel method is used to link a 2D kinetic Monte Carlo code to a 1D finite difference code to construct a more realistic and efficient tool for simulating various electrochemical processes. This multiscale model is able to simulate the long-scale mass transfer of electroactive species in bath along with electrode surface phenomena at atomic scale simultaneously. An embedded atom method (EAM) has been used to evaluate the barrier energies of diffusion and redox reactions on electrode surface. The FD code provides the ion concentration on OHP for KMC code, while the KMC code provides the surface activity and rate constants of redox reactions as an input data for FD code. The electrochemical...
Simultaneous voltammetric detection of ascorbic acid and uric acid at a carbon-paste modified electrode incorporating thionine-nafion ion-pair as an electron mediator
, Article Electrochimica Acta ; Volume 51, Issue 13 , 2006 , Pages 2599-2606 ; 00134686 (ISSN) ; Ghalkhani, M ; Sharif University of Technology
2006
Abstract
The electrochemical behavior of ascorbic acid (AA) and uric acid (UA) at the surface of a carbon-paste electrode modified with incorporate thionine-nafion ion-paired was thoroughly investigated. The results show the presence of nafion inside the matrix of modified electrode, because of the effective ion-pairing and hydrophobic interactions, significantly enhances the stability of thionine as an electron mediator inside the modified electrode. A high reproducibility in voltammetric response to analyte species results because of this enhancement. The cyclic voltammetric studies using the prepared modified electrode show the best electrocatalytic property for the electro-oxidation of AA and...
A kinetic study on the electrodeposition of cadmium with the presence of organic agents in sulfate solutions
, Article Materials Chemistry and Physics ; Volume 94, Issue 1 , 2005 , Pages 23-28 ; 02540584 (ISSN) ; Afshar, A ; Ghasemi, H ; Sharif University of Technology
2005
Abstract
The electrodeposition of cadmium is studied by electrochemical techniques with the presence of the organic agents. The cyclic voltammetry results clearly show that the electrodeposition of cadmium is a diffusion-controlled process associated with a typical nucleation process. With addition of the thiourea, 3-Picolin and benzyl alcohol organic agents simultaneously in sulfate solution, the redox potential of cadmium is shifted to more negative potentials. In this case, the current transients reveal an instantaneous nucleation with a typical three-dimensional (3D) growth mechanism, while it shows progressive nucleation mechanism without the ternary-species organic agents. In addition, the...
Synthesis, characterization, electrochemical studies and catecholase-like activity of a series of mononuclear Cu(II), homodinuclear Cu(II)Cu(II) and heterodinuclear Cu(II)Ni(II) complexes of a phenol-based compartmental ligand
, Article Journal of Molecular Catalysis A: Chemical ; Volume 241, Issue 1-2 , 2005 , Pages 1-7 ; 13811169 (ISSN) ; Behzad, M ; Bezaatpour, A ; Sharif University of Technology
2005
Abstract
A series of previously reported mononuclear Cu(II) and homodinuclear Cu(II)Cu(II) complexes, as well as, novel mononuclear Cu(II), homodinuclear Cu(II)Cu(II), and heterodinuclear Cu(II)Ni(II) complexes of a phenol-based dinucleating ligand with two different N(amine)2O2 and N(imine)2O2 coordination sites, were synthesized and characterized by elemental analyses, infrared and electronic absorption spectroscopies and conductivity measurements. The electrochemical behavior and catecholase-like activity of the complexes were also studied using cyclic voltammetry and UV-vis spectrophotometry, respectively. Our results show that the dinuclear complexes are more effective catalysts in the oxidation...
An electrochemical study of Au-Ni alloy electrodeposition from cyanide-citrate electrolytes
, Article Journal of Electroanalytical Chemistry ; Volume 577, Issue 1 , 2005 , Pages 1-8 ; 15726657 (ISSN) ; Ghorbani, M ; Ahmadi, M. R ; Sharif University of Technology
Elsevier
2005
Abstract
Cyclic voltammetry, j-t transients and transient time measurements have been used to characterize the Au-Ni alloy deposition and to obtain the nucleation and growth mechanism. The electrodeposition of gold, nickel and gold-nickel alloys was studied in cyanide-citrate electrolytes. The analysis of the voltammograms and j-t transients clearly shows that deposition of the Au and hence, of Au-Ni alloys, is affected by adsorbed cyanide ligands mainly at low overpotentials and a direct reduction occurs at high overpotentials. In this case, the Au deposition is kinetically favored, while the Ni deposition is controlled by the cyanide-citrate adsorbed adlayer. In an alloy electrolyte, the Au and Ni...
Three-dimensional hybrid graphene/nickel electrodes on zinc oxide nanorod arrays as non-enzymatic glucose biosensors
, Article Sensors and Actuators, B: Chemical ; Volume 251 , 2017 , Pages 462-471 ; 09254005 (ISSN) ; Aashuri, H ; Simchi, A ; Sharif University of Technology
Elsevier B.V
2017
Abstract
We present a novel hybrid electrode based on reduced graphene oxide/nickel/zinc oxide heterostructures. The sensor was fabricated by template-free hydrothermal growth of ZnO nanorod arrays on conductive glass substrates (FTO) followed by conformal electrodeposition of nickel nanoparticles with an average size of 18 nm. Then, in-situ reduction and electrophoretic deposition of graphene oxide (GO) nanosheets on the structured ZnO/Ni electrode was performed. The prepared three-dimensional nanostructure exhibited fast electrocatalytic response (<3 s) towards glucose oxidation due to the large surface area and high electro-activity. The prepared biosensor possessed a wide linear range over...
Modification of Additively Manufactured Stainless Steel 316L Electrodes by Fe-Co-Ni Metal-Organic Framework and Gold Nanoparticle for Electrochemical Water Splitting and CO2 Reduction
, M.Sc. Thesis Sharif University of Technology ; Simchi, Abdolreza (Supervisor)
Abstract
The processes of electrochemical water splitting and carbon dioxide reduction are among novel technologies that have gained attention for tackling climate change and global warming. Though, catalysts with fininancial justification for industrial utilization of these processes is still not available. In this study, a 3D-structured electrode of low-carbon 316 stainless steel, made by additive manufacturing, is modified with a trilayered metal-organic framework (MOF), with Iron, Cobalt, and Nickel metallic nodes and BDC-NH2 as the organic ligand, for water splitting. Also, the same steel electrode is modified with a single layered MOF, with Iron node and BDC-NH2 ligand, along with nanoparticles...
Removal of Micropollutants from Wastewater Using an Electrochemical Biomembrane Reactor
, M.Sc. Thesis Sharif University of Technology ; Ghasemian, Saloumeh (Supervisor) ; Ghobadinejad, Zahra (Co-Supervisor) ; Hamzehlouyan, Tayebeh (Co-Supervisor)
Abstract
One of the major environmental problems in recent years is the presence of micropollutants that cause many problems for the environment and living organisms. Diclofenac is one of the micropollutants and endocrine disruptors. Conventional treatment methods do not have the ability to effectively remove pharmaceutical pollutants and micro-pollutants, and finding a suitable approach to remove these pollutants is of great importance. In recent years, biological methods such as the use of enzymes and molds have received attention, but due to the relative removal of pollutants, these methods have been combined with membrane technology to improve the level of pollutant removal and increase the...
Simulation of mixed electroosmotic/pressure-driven flows by utilizing dissipative particle dynamics
, Article Microfluidics and Nanofluidics ; Vol. 17, issue. 1 , July , 2014 , pp. 199-215 ; ISSN: 16134982 ; Noruzitabar, M ; Mehboudi, M ; Sharif University of Technology
Abstract
In this paper, we present an extension of dissipative particle dynamics method in order to study the mixed electroosmotic/pressure-driven micro- or nano-flows. This method is based on the Poisson-Boltzmann equation and has a great potential to resolve the electric double layer (EDL). Hence, apart from studying the bulk flow, it also provides a strong capability in order to resolve the complex phenomena occur inside the EDL. We utilize the proposed method to study the pure electroosmotic and also the mixed electroosmotic/pressure-driven flow through the straight micro-/nano-channels. The obtained results are in good agreement with the available analytical solutions. Furthermore, we study the...
Highly sensitive 3D gold nanotube ensembles: Application to electrochemical determination of metronidazole
, Article Electrochimica Acta ; Volume 106 , 2013 , Pages 288-292 ; 00134686 (ISSN) ; Ghorbani, M ; Ghalkhani, M ; Vossoughi, M ; Dolati, A ; Sharif University of Technology
2013
Abstract
Three-dimensional gold nanoelectrode ensembles (3D GNE) have proven to be promising nanoelectrodes by representing much higher sensitivity compared to both their 2D nanostructures and bulk counterparts. The sensitivity of 3D gold nanotubes (GNTs) fabricated through electrodeposition inside the pores of polycarbonate templates, was examined toward metronidazole (MTZ) as one of their pharmaceutical applications. The electrochemical behavior of MTZ at the 3D GNT-modified electrode was discussed in detail through cyclic voltammetry (CV) which suggested an irreversible reduction of nitro group to the corresponding hydroxylamine and a subsequently reversible redox peak for the corresponding...
Gold extraction from an oxide ore in iodine-iodide solutions
, Article Industrial Electrochemistry and Electrochemical Engineering General Session - 220th ECS Meeting, Boston, MA, 9 October 2011 through 14 October 2011 ; Volume 41, Issue 17 , 2012 , Pages 53-60 ; 19385862 (ISSN) ; 9781607683070 (ISBN) ; Sharif University of Technology
Abstract
Two types of gold ores were subjected to iodide/iodine leaching at room temperature. The effects of three factors, including ore type (a carbonaceous and an oxide gold ores), iodide/iodine concentration, and the presence of oxygen in solution on gold leaching performance were investigated. The carbonaceous ore showed only 20% gold extraction into the solution; since gold-iodide complexes would readily adsorb on organic matter. In contrast, gold extraction from the oxide ore in a solution containing 20 g/L iodide and 4 g/L iodine reached 77% in 6 h and 89% in 24 h. With iodate as the oxidant, no gold could be leached in 48 hours. When the iodate was partially converted to iodine by adding HCl...
A novel screen-printed TiO2 photoelectrochemical sensor for direct determination and reduction of hexavalent chromium
, Article Electrochemistry Communications ; Volume 61 , 2015 , Pages 110-113 ; 13882481 (ISSN) ; Goh, G. K. L ; Dolati, A ; Ghorbani, M ; Sharif University of Technology
Elsevier Inc
2015
Abstract
A novel and simple photoelectrochemical (PEC) sensor to detect Cr(VI) based on screen-printed TiO2 modified with gold nanoparticles is presented. The proposed PEC sensor showed a very low detection limit (S/N = 3) of 0.004 μM, over a wide linear concentration range from 0.01 μM to 100 μM with a high sensitivity of 11.88 μA.μM-1 Cr(VI). Results also indicated good anti-interference and superb recovery in natural media application for Cr(VI) sensing
Impact of chromium doping on physical, optical, electronic and photovoltaic properties of nanoparticle TiO2 photoanodes in dye-sensitized solar cells
, Article New Journal of Chemistry ; Volume 41, Issue 23 , 2017 , Pages 14516-14527 ; 11440546 (ISSN) ; Mohammadi, M. R ; Sharif University of Technology
Royal Society of Chemistry
2017
Abstract
Herein, we report the impact of chromium doping on the physical properties, electronic band structure and photovoltaic characteristics of their corresponding devices based on dye-sensitized solar cells (DSCs). Different DSCs with various compositions of the photoanode electrodes are fabricated to study their optical, structural, conduction band edge, donor density, depth of trap states and photoelectrochemical properties using X-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS), field-emission scanning electron microscopy (FE-SEM), Mott-Schottky capacitance analysis, chemical capacitance and electrochemical impedance spectroscopy (EIS) measurements. For such studies, the Cr-doped...