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    Investigation on Optical and Catalytic Properties of Noble Metallic Nanoparticles in SiO2 and TiO2 Matrix

    , Ph.D. Dissertation Sharif University of Technology Sangpour, Parvaneh (Author) ; Moshfegh, Alireza (Supervisor) ; Akhavan, Omid (Supervisor)
    Doping metal or semiconductor nanoparticles in transparent matrix have attracted much attention for practical application in recent years. From fundamental veiw point, limiting the charge carriers and exitons in nanometric scales resulted in new quantum phenomena. In this context, transparent films containing metal nanoparticles shows an absorption peak in visible region of spectrom. Thus, by choosing an appropriate metal and controlling the size and concentration of particles in corresponding matrix, we can provide coatings with a wide rang of colors. Furthermore, thin films containing metal or metal oxide nanoparticles had been considered as nanostructure materials in research and... 

    Synthesis of Nanoparticles by Electrical Arc Discharge in Liquid Media and Characterization

    , Ph.D. Dissertation Sharif University of Technology Ashkarran, Ali Akbar (Author) ; Iraji Zad, Azam (Supervisor) ; Mahdavi, Mohammad (Supervisor)
    In this research we focus on synthesis and analysis of metal and metal oxide nanoparticles and their photocatalytic activity. At the beginning a high current DC power supply and a reactor for the electrical arc discharge process designed and implemented. Several nanoparticles such as tungsten oxide, zinc oxide, silver and gold have synthesized by this method in deionized water, deionized water including surfactants and stabilizers and analyzed. Several characterization techniques such as X-ray diffraction (XRD), dynamic light scattering (DLS) X-ray photoelectron spectroscopy (XPS), BET, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV-Vis spectroscopy have... 

    Separation and Preconcentration of Gold and Silver Nanoparticles Using Cloud Point Extraction

    , M.Sc. Thesis Sharif University of Technology Zare-moghadam, Mousa (Author) ; Hormozi-Nezhad, M.R (Supervisor)
    Separation and identification of metal nanoparticles in surface water samples such as river water is very important. Nanoparticles specially metal nanoparticles have small dimensions can easily pass through from the body's outer immune system and disrupt biological function. Most of the nanoparticles have active surface so environmental contaminants can be absorbed on their surface and then can penerated in the body, and they may cause disease. Therefore determination of nanoparticles type and concentrations and their separation from the surrounding environment, especially surface waters is important. Separation and preconcentration of metal nanoparticles was done by using cloud point... 

    Preparation and Investigation of the Electrochemical Behavior of Sensors Based on Glassy Carbon Electrode Modified with Various Carbon Nanostructures Decorated by Some of Metal Nanoparticlesfor Determination of Ceftizoxime

    , M.Sc. Thesis Sharif University of Technology Ranjbar, Saba (Author) ; Shahrokhian, Saeed (Supervisor) ; Masoumeh Ghalkhani (Co-Advisor)
    In the recent years, sensors and biosensors attracts much attentions as a suitable devices in analytical chemistry. In this meantime carbon nanostructures and metal nanoparticles act as a good choice owing to their unique properties such as high electrical conductivity andmechanical and chemical stability in modification of the surface of sensors and biosensors. Because of importance of analysis the trace amounts of pharmaceutical and biological compounds, in this studies the surface of glassy carbon electrode was modified with some carbon nanostructures and metal nanoparticles for electrochemical investigation and determination of pharmaceutical and clinical compounds.In the first work, a... 

    Application of Metallic Nanoparticles in Treatment of Wastewater Containing Dyestuffs

    , M.Sc. Thesis Sharif University of Technology Hosseini, Reza (Author) ; Shaygan, Jalalaldin (Supervisor)
    Textile industrial wastewaters are one of the most important sources of environmental contaminants. In the recent years, use of advanced oxidation processes, by producing highly active and reactive components such as hydroxyl radicals has been proposed. The aim of this research is oxidative degradation of methylene blue dye using Cu-nanoparticles immobilized on a polymer support with H2O2 as an oxidant reagent.In general, oxidative degradation of methylene blue with hydrogen proxide in the presence of immobilized CuO nanoparticles on a polymer support as the catalyst was studied. We used polyamidoamine (PAMAM) dendrimer as the polymer support for nanoparticles. fourth generation of PAMAM was... 

    Preparation of Metal Nanoparticles/Ionic Liquid Composites and Investigation of Their Catalytic Activity

    , M.Sc. Thesis Sharif University of Technology Gharegozloo, Nazanin (Author) ; Gholami, Mohammad Reza (Supervisor) ; Salari, Hadi (Co-Advisor)
    In this research Fe3O4 magnetic nanoparticles were prepared. To protect against oxidation, a shell of SiO2 was deposited on Fe3O4. Graphene oxide was prepared by the modified Hummer method and supported on the Fe3O4@SiO2 core-shell. Then, ionic liquid layer was impregnated on it. Afterward, PtAu nano alloy were synthesized on the surface of nanocomposite with the different molar ration including 100:0, 75:25, 50:50, 25:75 and 0:100. The as-prepared nanocomposite was characterized by SEM, XRD, and FT-IR analytical methods.For investigation of kinetically activity of catalysts, reduction of 4-nitrophenol with NaBH4 as reducer was used. The adsorption in different times was obtained by UV-vis... 

    Synthesis and Characterization of TiO2 and WO3 Thin Film Photoanodes Containing Noble Metal Nanoparticles and (TiO2)x-(ZnO)1-x Nanocomposite Photanodes for H2 Production

    , Ph.D. Dissertation Sharif University of Technology Naseri Taheri, Naimeh (Author) ; Moshfegh, Ali Reza (Supervisor)
    Growing demand on energy and limitation and consequence of fossil fuels have caused to utilize the clean and renewable energy sources. Hydrogen is a clean energy carrier which produced just water vapor during combustion. Today, methods which are usually used to produce this fuel are based on using fossil fuel compounds. Therefore, utilizing new production methods is unavoidable. One of these methods is using semiconductors such as TiO2 to spilt water and produce H2 by solar irradiation. Reducing the energy gap of these semiconductors to match the solar spectrum, specially in its visible range, modification of their structures, surfaces and stability are the main challenges in hydrogen... 

    Highly Sensitive Detection of Captopril by Fluorescein-5-Isothiocyanate-Modified Gold Nanoparticles Based on FRET& Antioxidant Activity Assay in Iranian Tea Using the Generation and Growth of Metalic Nanoparticles

    , M.Sc. Thesis Sharif University of Technology Bohloul, Arash (Author) ; Bagheri, Habib (Supervisor) ; Hormozi Nezhad, Mohammad Reza (Supervisor)
    The research of this work was divided into two parts. First, A novel fuorescence sensor based on fluorescence resonance energy transfer for the determination of captopril was developed. FITC molecules that are highly fluorescent in alkaline solution fluoresce weakly when they are adsorbed onto AuNP surfaces (based on affinity of AuNPs and isothiocyanate group on FITC) as a result of fluorescence resonance energy transfer. In the presence of captopril, FITC molecules are released from the AuNP surface in order to stronger affinity to AuNPs surface than FITC molecule (in order to thiol group in captopril) so the florescence intensity of FITC restore. This phenomenon was used for quantitative... 

    Synthesis of Novel Bimetallic Nanocomposite of Copper and Silver Based on Metal Organic Frameworks and Investigation of Its Application as Catalyst in Sulfonation Reaction

    , M.Sc. Thesis Sharif University of Technology Yaghoubnejad Pazoki, Parisa (Author) ; Matloubi Moghaddam, Firouz (Supervisor)
    In recent years, bimetallic metal-organic frameworks have attracted the great attention of researchers due to their dual properties and synergistic effects. In this research and inspired by green chemistry, the synthesis of a magnetic nanocomposite of the defective green metal-organic framework was implemented, which carries metallic silver nanoparticles (Ag NPs@Cu-MOF). Then, the sulfonated compounds were synthesized with the prepared nanocomposite because of the importance and widespread medicinal use of sulfur-containing compounds especially sulfonated compounds, and the difficulty of their preparation methods. It is noteworthy to mention that the sulfonation reaction was done by... 

    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... 

    Advances in skin regeneration: application of electrospun scaffolds

    , Article Advanced Healthcare Materials ; Volume 4, Issue 8 , 2015 , Pages 1114-1133 ; 21922640 (ISSN) Norouzi, M ; Boroujeni, S. M ; Omidvarkordshouli, N ; Soleimani, M ; Sharif University of Technology
    Wiley-VCH Verlag  2015
    The paucity of cellular and molecular signals essential for normal wound healing makes severe dermatological ulcers stubborn to heal. The novel strategies of skin regenerative treatments are focused on the development of biologically responsive scaffolds accompanied by cells and multiple biomolecules resembling structural and biochemical cues of the natural extracellular matrix (ECM). Electrospun nanofibrous scaffolds provide similar architecture to the ECM leading to enhancement of cell adhesion, proliferation, migration and neo tissue formation. This Review surveys the application of biocompatible natural, synthetic and composite polymers to fabricate electrospun scaffolds as skin... 

    Gold nanoparticles functionalized with fullerene derivative as an effective interface layer for improving the efficiency and stability of planar perovskite solar cells

    , Article Advanced Materials Interfaces ; Volume 7, Issue 21 , 2020 Chavan, R. D ; Prochowicz, D ; Bończak, B ; Tavakoli, M. M ; Yadav, P ; Fiałkowski, M ; Hong, C. K ; Sharif University of Technology
    Wiley-VCH Verlag  2020
    Titanium dioxide (TiO2) is an extensively used electron transporting layer (ETL) in n–i–p perovskite solar cells (PSCs). Although, TiO2 ETL experiences the high surface defect together with low electron extraction ability, which causes severe energy loss and poor stability in the PSC. In this study, a new intermediate layer consisting of gold nanoparticles functionalized with fully conjugated fullerene C60 derivative (C60-BCT@Au NPs) that enhances the interfacial contact at ETL/perovskite interface leading to a perovskite film with improved crystallinity and morphology is reported. Moreover, the studies demonstrate that the interface modification of the TiO2 ETL with C60-BCT@Au NPs... 

    Noble metal nanoparticles in biosensors: Recent studies and applications

    , Article Nanotechnology Reviews ; Volume 6, Issue 3 , 2017 , Pages 301-329 ; 21919089 (ISSN) Malekzad, H ; Sahandi Zangabad, P ; Mirshekari, H ; Karimi, M ; Hamblin, M. R ; Sharif University of Technology
    Walter de Gruyter GmbH  2017
    The aim of this review is to cover advances in noble metal nanoparticle (MNP)-based biosensors and to outline the principles and main functions of MNPs in different classes of biosensors according to the transduction methods employed. The important biorecognition elements are enzymes, antibodies, aptamers, DNA sequences, and whole cells. The main readouts are electrochemical (amperometric and voltametric), optical (surface plasmon resonance, colorimetric, chemiluminescence, photoelectrochemical, etc.) and piezoelectric. MNPs have received attention for applications in biosensing due to their fascinating properties. These properties include a large surface area that enhances biorecognizers... 

    Pulsed electrodeposition of gold nanoparticles on fluorine-doped tin oxide glass and absorption-based surface plasmon resonance evaluation

    , Article Journal of Nano Research ; Volume 33 , 2015 , Pages 11-26 ; 16625250 (ISSN) Vahdatkhah, P ; Sadrnezhaad, S. K ; Sharif University of Technology
    Trans Tech Publications Ltd  2015
    Synthesis and immobilization of Au nanoparticles (AuNPs) was performed on transparent fluorine-doped tin oxide (FTO) substrate by pulse electrodeposition method. The method was cost effective, simple and capable of producing nanoparticles strongly attached to the substrate. Effects of several influencing factors such as duty cycle, pulse frequency, current density, solution concentration, deposition period and annealing procedure on the optical properties of AuNPs-FTO electrode were investigated. AuNPs-FTO electrodes were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM) and UV-Vis absorption analysis. Controllability... 

    Utilizing the moiré deflectometry-based detection method improves the detection sensitivity for gold nanoparticles trapped by optical tweezers

    , Article Journal of the Optical Society of America B: Optical Physics ; Volume 38, Issue 7 , 2021 , Pages 2135-2140 ; 07403224 (ISSN) Reihani, S. N ; Khorshad, A. A ; Sharif University of Technology
    The Optical Society  2021
    Gold nanoparticles (GNPs) are very often used as handles for nanotechnological micromanipulation. In this regard, optical trapping of GNPs is of great importance, in which locating the trapped GNP within the focal spot with nanometer precision is crucial. Very recently, we have introduced a new position detection system for optical tweezers based on moiré deflectometry (MD). Here we show, both theoretically and experimentally, that an MD detection system could provide significantly larger detection sensitivity for a trapped GNP compared to that provided by conventional back focal plane (BFP) detection systems. For instance, for a trapped 200 nm GNP, the detection sensitivity provided by the... 

    Efficient and green oxidative degradation of methylene blue using Mn-doped ZnO nanoparticles (Zn1−xMnxO)

    , Article Journal of Experimental Nanoscience ; Volume 10, Issue 16 , 2015 , Pages 1256-1268 ; 17458080 (ISSN) Khaksar, M ; Amini, M ; Boghaei, D. M ; Sharif University of Technology
    Taylor and Francis Ltd  2015
    Mn-doped ZnO nanoparticles, Zn1−xMnxO, were synthesised by a polyethylene glycol (PEG) sol–gel method and the physicochemical properties of compounds were characterised by atomic absorption spectroscopy (AAS), energy-dispersive X-ray analysis, X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The catalytic degradation of an organic dye, methylene blue (MB), in the presence of Zn1−xMnxO as the catalyst and hydrogen peroxide (H2O2) as the oxidant at room temperature in water has been studied. Effects of oxidant, catalyst amount, catalyst composition, pH value of the solution and an OH-radical... 

    Nanomaterial-assisted pyrolysis of used lubricating oil and fuel recovery

    , Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; 2020 Alavi, E ; Abdoli, M. A ; Khorasheh, F ; Nezhadbahadori, F ; Bayandori Moghaddam, A ; Sharif University of Technology
    Taylor and Francis Inc  2020
    Used lubricating oil (ULO) is a heavy mixture of various hydrocarbons and needs to be treated before discharging. Considering ULO nature, it is more favorable to recover lighter hydrocarbon cuts from ULO, which not only improves the whole process economically, but also prevents the emission of hardly decomposable hydrocarbons into the environment. In this research, the potential of pyrolysis method for ULO recovery was studied. Furthermore, graphene nanoplatelets (GNP), γ- Fe2O3 and ZnO nanoparticles were used to improve the kinetics of the process and their impacts on the final product quality were evaluated. Based on the results, adding nanomaterials increased the tendency to produce gas... 

    Development of a colorimetric sensor array based on monometallic and bimetallic nanoparticles for discrimination of triazole fungicides

    , Article Analytical and Bioanalytical Chemistry ; April , 2021 ; 16182642 (ISSN) Kalantari, K ; Fahimi Kashani, N ; Hormozi Nezhad, M. R ; Sharif University of Technology
    Springer Science and Business Media Deutschland GmbH  2021
    Due to the widespread use of pesticides and their harmful effects on humans and wildlife, monitoring their residual amounts in crops is critically essential but still challenging regarding the development of high-throughput approaches. Herein, a colorimetric sensor array has been proposed for discrimination and identification of triazole fungicides using monometallic and bimetallic silver and gold nanoparticles. Aggregation-induced behavior of AgNPs, AuNPs, and Au-AgNPs in the presence of four triazole fungicides produced a fingerprint response pattern for each analyte. Innovative changes to the metal composition of nanoparticles leads to the production of entirely distinct response patterns... 

    Influence of Substrate, Additives, and Pulse Parameters on Electrodeposition of Gold Nanoparticles from Potassium Dicyanoaurate

    , Article Metallurgical and Materials Transactions B: Process Metallurgy and Materials Processing Science ; Volume 46, Issue 6 , December , 2015 , Pages 2584-2592 ; 10735615 (ISSN) Vahdatkhah, P ; Sadrnezhaad, S. K ; Sharif University of Technology
    Springer Boston  2015
    Gold nanoparticles (AuNPs) of less than 50 nm diameter were electrodeposited from cyanide solution by pulsating electric current on modified copper and indium tin oxide (ITO) films coated on glass. Morphology, size, and composition of the deposited AuNPs were studied by X-ray photoelectron spectroscopy, atomic force microscopy, and field emission scanning electron microscopy. Effects of peak current density, pulse frequency, potassium iodide and cysteine on grain size, and morphology of the AuNPs were determined. Experiments showed that cathode current efficiency increases with the pulse frequency and the iodide ion. Size of the AuNPs increased with the current density. The number of... 

    Selective fluorometric determination of sulfadiazine based on the growth of silver nanoparticles on graphene quantum dots

    , Article Microchimica Acta ; Volume 187, Issue 1 , 2020 Afsharipour, R ; Haji Shabani, A. M ; Dadfarnia, S ; Kazemi, E ; Sharif University of Technology
    Springer  2020
    A sensitive fluorometric assay is described for the direct determination of the antibiotic sulfadiazine. Silver nanoparticles placed on graphene quantum dots (Ag NP-GQDs) were synthesized by reduction of AgNO3 with sodium borohydride in the presence of GQDs. The growth of Ag NPs on the surface of the GQDs causes quenching of the blue fluorescence of the GQDs with an emission maximum at 470 nm by surface-enhanced energy transfer. If sulfadiazine is added, it interacts with Ag NPs and fluorescence is restored. Under optimal conditions, the fluorescence increases linearly in the sulfadiazine concentration range of 0.04–22.0 μM. The detection limit is 10 nM with relative standard deviations of...