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    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... 

    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... 

    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... 

    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... 

    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... 

    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 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... 

    Shed light on submerged DC arc discharge synthesis of low band gap gray Zn/ZnO nanoparticles: Formation and gradual oxidation mechanism

    , Article Advanced Powder Technology ; Volume 29, Issue 5 , 2018 , Pages 1246-1254 ; 09218831 (ISSN) Ziashahabi, A ; Poursalehi, R ; Naseri, N ; Sharif University of Technology
    Elsevier B.V  2018
    Synthesis of colloidal metal oxides with controllable size and morphology is burgeoning field of research in nanoscience. Low band gap gray Zn/ZnO colloidal nanoparticles were fabricated by plasma-liquid interaction of DC arc discharge in water. Scanning electron microscopy, X-ray diffraction and UV–vis spectroscopy were employed for morphology, crystal structure and optical characterizations respectively. Optical emission spectroscopy was used to investigate the plasma properties during the synthesis and formation mechanism of nanoparticles. Nanoparticles with different size and shape were fabricated only by adjusting discharge current during synthesis without introducing any chemical... 

    Optical concentration of gold nanoparticles as a new concept of analytical sensitivity

    , Article Instrumentation Science and Technology ; 2020 Vaziri Heshi, S ; Shokoufi, N ; Seyed Reihani, S. N ; Sharif University of Technology
    Bellwether Publishing, Ltd  2020
    Concentration procedures have always been implemented when trace analysis of compounds in real matrices is contemplated. A variety of concentration strategies have been reported aiming at decreasing the limits of detection (LODs). The optical concentration of the substance in solution is one of the novel concepts for the enhancement of the analytical sensitivity. In this study, the optical concentration has been measured by the trapping of gold nanoparticles ((Formula presented.) nm) dispersed in water at low-concentrations at the focal volume of the laser beam. The influence of factors such as the time of gold nanoparticle trapping, the size of the nanoparticles, the intensity of the laser... 

    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... 

    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... 

    Application of the combined neuro-computing, fuzzy logic and swarm intelligence for optimization of compocast nanocomposites

    , Article Journal of Composite Materials ; Volume 49, Issue 13 , 2015 , Pages 1653-1663 ; 00219983 (ISSN) Tofigh, A. A ; Rahimipour, M. R ; Shabani, M. O ; Davami, P ; Sharif University of Technology
    SAGE Publications Ltd  2015
    In the last few years, an increasing attention has been paid to the issues of saving energy and reducing the manufacturing costs in the transport industry which necessitates further efforts to replace traditional materials like steel with lightweight materials such as plastics, aluminum, magnesium, and composites. Metal matrix nanocomposites have turned into an established material in today's industry with an ongoing expansion in their field of applications. In this study, the formation of nanoparticle-aluminum metal matrix composites is described by compocast processing from nanoparticle Al2O3 and the A356 aluminum alloy. In order to optimize the processing parameters, a novel approach is... 

    Supercritical synthesis of a magnetite-reduced graphene oxide hybrid with enhanced adsorption properties toward cobalt & strontium ions

    , Article RSC Advances ; Volume 6, Issue 17 , 2016 , Pages 13898-13913 ; 20462069 (ISSN) Tayyebi, A ; Outokesh, M ; Sharif University of Technology
    Royal Society of Chemistry  2016
    The current study presents a supercritical synthesis of magnetite-reduced graphene oxide (M-RGO) in methanol media, in which Fe3O4 nanoparticles are simultaneously formed, surface modified and decorated on the surface of the reduced graphene oxide. Simulations using density functional theory, which were performed using the M06-2x/cc-pVDZ level of theory, indicate that upon adsorption of a Fe3O4 cluster on the graphene, the overall charge on the graphene surface becomes about -0.0236e, indicating charge transfer from the Fe3O4 cluster to the graphene surface. Instrumental and chemical analyses exhibited the formation of strong bonds between Fe3O4 and graphene, through C-O-Fe and C-Fe bridges.... 

    Application of silver nanoparticles and principal component-artificial neural network models for simultaneous determination of levodopa and benserazide hydrochloride by a kinetic spectrophotometric method

    , Article Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy ; Volume 82, Issue 1 , November , 2011 , Pages 25-30 ; 13861425 (ISSN) Tashkhourian, J ; Hormozi Nezhad, M. R ; Khodaveisi, J ; Sharif University of Technology
    A multicomponent analysis method based on principal component analysis-artificial neural network model (PC-ANN) is proposed for the simultaneous determination of levodopa (LD) and benserazide hydrochloride (BH). The method is based on the reaction of levodopa and benserazide hydrochloride with silver nitrate as an oxidizing agent in the presence of PVP and formation of silver nanoparticles. The reaction monitored at analytical wavelength 440 nm related to surface plasmon resonance band of silver nanoparticles. Differences in the kinetic behavior of the levodopa and benserazide hydrochloride were exploited by using principal component analysis, an artificial neural network (PC-ANN) to resolve... 

    Utilizing graphene oxide/gold/methylene blue ternary nanocomposite as a visible light photocatalyst for a plasmon-enhanced singlet oxygen generation

    , Article Reaction Kinetics, Mechanisms and Catalysis ; Volume 135, Issue 5 , 2022 , Pages 2851-2865 ; 18785190 (ISSN) Tamtaji, M ; Kazemeini, M ; Sharif University of Technology
    Springer Science and Business Media B.V  2022
    In this study, graphene oxide/gold/methylene blue (GO/Au/MB) ternary composites were synthesized and characterized through UV–vis, FTIR, XRD, XPS, SEM, and TEM analyses towards plasmon-enhanced singlet oxygen (1O2) generation. Through using gold nanoparticles and MB photosensitizers, the visible light adsorption capability of GO was enhanced by 115%. Moreover, applying this ternary composite as a photocatalyst under visible light interestingly revealed a drastic step-increase of 14% (i.e., from 9 to 23%) in the conversion of photooxygenation of Anthracene. This behavior was rationalized using finite-difference time-domain (FDTD) simulations which confirms the plasmonic field of gold... 

    Rheology and colloidal structure of silver nanoparticles dispersed in diethylene glycol

    , Article Powder Technology ; Volume 197, Issue 1-2 , 2010 , Pages 49-53 ; 00325910 (ISSN) Tamjid, E ; Guenther, B. H ; Sharif University of Technology
    Rheological behavior of agglomerated silver nanoparticles (~ 40 nm) suspended in diethylene glycol over a wide range of volumetric solids concentrations (φ{symbol} = 0.11-4.38%) was studied. The nanoparticle suspensions generally exhibited a yield pseudoplastic behavior. Bingham plastic, Herschel-Bulkley and Casson models were used to evaluate the shear stress-shear rate dependency. Analyzing the effect of silver concentrations on the yield stress and viscosity of the suspensions followed an exponential form, revealing an increase in the degree of interparticle interactions with increasing solid concentrations. Fractal dimension (Df) was estimated from the suspension yield stress and... 

    Selective colorimetric detection of pentaerythritol tetranitrate (PETN) using arginine-mediated aggregation of gold nanoparticles

    , Article Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy ; Volume 228 , 2020 Taefi, Z ; Ghasemi, F ; Hormozi Nezhad, M. R ; Sharif University of Technology
    Elsevier B.V  2020
    Detection of pentaerythritol tetranitrate (PETN) as an explosive has been of great interest because of public safety and military concerns. Here, we have presented a simple, selective and sensitive colorimetric method for direct detection of PETN. The gold nanoparticles (AuNPs) were first exposed to arginine which has primary amines in its structure. Electron deficient –NH2 groups from arginine could strongly interact with –NO2 groups of PETN as electron donors. Hydrogen bonding happens between the –NO2 group of PETN and –NH2 group of arginine molecules. Therefore, selective aggregation of AuNPs happened because of the donor-acceptor and hydrogen bonding interactions. Due to the aggregation,... 

    Photocatalytic degradation of methylene blue by TiO2-capped ZnO nanoparticles

    , Article 2nd International Congress on Ceramics, ICC 2008, Verona, 29 June 2008 through 4 July 2008 ; 2008 ; 9788880800842 (ISBN) Simchi, A ; Lak, A ; Nemati, Z. A ; SACMI; Iris Ceramica; SITI - B and T Group; Element Six; Corning ; Sharif University of Technology
    ZnO nanoparticles were fabricated via hydrothermal method and an amorphous TiO2 layer was then coated on the nanoparticles via sol-gel route. X-ray diffraction (XRD) and transmission electron microscopy (TEM) studies showed that the synthesized ZnO nanoparticles were hexagonal with wurtzite structure and an average particle size of 38 nm. The thickness of the titanium oxide layer was determined to be 20-40 nm. The photocatalytic decolorization of Methylene blue under UV irradiation indicated that as-prepared TiO 2-capped ZnO is inferior than ZnO particles. Nevertheless, calcinations of the particles at 350 °C for 24 h significantly improved the photo-activity of the ZnO/TiO2 core/shell...