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    Nano sized ZnO composites: Preparation, characterization and application as photocatalysts for degradation of AB92 azo dye

    , Article Materials Science in Semiconductor Processing ; Volume 21 , May , 2014 , Pages 167–179 Mohaghegha, N. (Neda) ; Tasviri, M. (Mahboubeh) ; Rahimic, E. (Esmail) ; Gholamia, M. R. (Mohammad Reza) ; Sharif University of Technology
    Abstract
    ZnO and Mordenite zeolite (MOR) nanoparticles were prepared by precipitation process using ultrasonic irradiation and hydrothermal method, respectively. Supported ZnO catalysts were prepared and the effect of different supports on the photocatalytic activity of ZnO nanoparticles was investigated. All prepared samples were characterized by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Fourier Transform-Infra Red Spectroscopy (FTIR), UV–vis spectroscopy (UV–vis) and BET surface area technique. The photocatalytic activity of the synthesized catalysts was elucidated using the photo-oxidation of Acid Blue 92 (AB92) as a hazardous pollutant under UV light. The effect of different... 

    Photocatalytic decolorization of methylene blue using immo bilized ZnO nanoparticles prepared by solution combustion method

    , Article Desalination and Water Treatment ; Volume 44, Issue 1-3 , May , 2012 , Pages 174-179 ; 19443994 (ISSN) Rezaee, A ; Masoumbeigi, H ; Soltani, R. D. C ; Khataee, A. R ; Hashemiyan, S ; Sharif University of Technology
    Taylor and Francis Inc  2012
    Abstract
    Photocatalytic decolorization of methylene blue (MB) in aqueous solution was investigated using ZnO nanoparticles immobilized on glass plate. The ZnO nanoparticles were prepared by solution combustion method (SCM) using zinc nitrate as oxidant and glycine as fuel. In the slurry ZnO system the separation and recycling of the photocatalyst is practically difficult. Thus, the ZnO nanoparticles were immobilized on glass supports to solve this problem. The effects of process parameters like, catalyst loading, initial dye concentration, and UV-radiation intensity have been investigated. The best results of MB removal were reported in the 1800 μW cm-2 UVC using two layers immobilized ZnO... 

    Detecting intermediate particles in the growth of colloidal zinc oxide nanoparticles in different chemical routes using MCR-ALS

    , Article Journal of Chemometrics ; Volume 27, Issue 10 , 2013 , Pages 353-358 ; 08869383 (ISSN) Hormozi Nezhad, M. R ; Jalali Heravi, M ; Kafrashi, F ; Sharif University of Technology
    2013
    Abstract
    Zinc oxide (ZnO) nanoparticles have been used in a wide-ranging of applications such as transparent UV protection, light emitting diodes, sensors and photovoltaic cells. Many applications of ZnO nanoparticles could be improved by changing the particle size, shape and morphology. Therefore, studying the mechanism of shape evolution is crucial for size and shape controlled synthesis of nanocrystaline ZnO particles. As an alternative to sophisticated techniques such as transmission electron microscopy (TEM) and X-ray powder diffraction (XRD), commonly used for studying nanoparticles evolution, we herein employed UV/Vis spectroscopy for monitoring the evolution process of the ZnO nanocrystals... 

    Comparative photodecolorization of red dye by anatase, rutile (TiO 2), and wurtzite (ZnO) using response surface methodology

    , Article Turkish Journal of Chemistry ; Volume 36, Issue 1 , 2012 , Pages 121-135 ; 13000527 (ISSN) Asl, S. K ; Sadrnezhaad, S. K ; Rad, M. K ; Üner, D ; Sharif University of Technology
    2012
    Abstract
    Treatment of dye pollution containing C.I. Acid Red 14 (AR14) by a coupled photocatalytic process was studied. Titanium dioxide, in the form of anatase and rutile, and zinc oxide, were used as photocatalysts. The investigated photocatalysts were Aldrich-produced nanopowders with crystallites of a mean size of 20-30 nm and a specific surface area of about 50 m 2/g. A comparison of TiO 2(anatase), TiO 2(rutile), TiO 2(a,r), and ZnO for the decolorization of the AR14 solution was performed. Results showed that color removal followed the decreasing order of TiO 2(a,r), ZnO > TiO 2(a,r) > TiO 2(a), ZnO > TiO 2(r), ZnO >TiO 2(a,r) > TiO 2(a) > ZnO > TiO 2(r). Response surface methodology (RSM) was... 

    ZnO nanoparticles: An efficient nanocatalyst for the synthesis of β-acetamido ketones/esters via a multi-component reaction

    , Article Catalysis Communications ; Volume 9, Issue 2 , 2008 , Pages 299-306 ; 15667367 (ISSN) Mirjafary, Z ; Saeidian, H ; Sadeghi, A ; Matloubi Moghaddam, F ; Sharif University of Technology
    2008
    Abstract
    A convenient one-pot multi-component reaction of aromatic aldehydes, enolizable ketones or β-keto esters and acetonitrile in the presence of acetyl chloride and 10 mol% ZnO nanoparticles for the synthesis of β-acetamido ketones/esters at room temperature is described. © 2007 Elsevier B.V. All rights reserved  

    Preparation and characterization of ZnO nanoparticles by a novel sol-gel route

    , Article Materials Letters ; Volume 61, Issue 14-15 , 2007 , Pages 3265-3268 ; 0167577X (ISSN) Vafaee, M ; Sasani Ghamsari, M ; Sharif University of Technology
    2007
    Abstract
    In this study, ZnO nanoparticles with 3 to 4 nm size and spherical shape have been prepared. For the first time, TEA (triethanolamine) as a surfactant has been used for the preparation of ZnO nanoparticles. The best concentration of each component was adjusted through comparison between different sol absorption spectra. The best sol regarding its optical property was subjected to analysis by photoluminescence spectroscopy. TEM micrograph and electron diffraction pattern of these particles were obtained to represent the morphology and crystalline phase of the particles, respectively. Experimental results have shown that the prepared zinc oxide nanoparticles by this method have higher... 

    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
    Abstract
    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... 

    Facile synthesis of highly substituted 2-pyrone derivatives via a tandem Knoevenagel condensation/lactonization reaction of β-formyl-esters and 1,3-cyclohexadiones

    , Article Tetrahedron Letters ; Vol. 55, issue. 18 , April , 2014 , p. 2908-2911 ; ISSN: 00404039 Moghaddam, F. M ; Mirjafary, Z ; Javan, M. J ; Motamen, S ; Saeidian, H ; Sharif University of Technology
    Abstract
    A mild and efficient tandem process for the synthesis of new highly substituted 2-pyrones starting from commercially available 2-arylacetic acids has been developed. The synthesis is based on the Knoevenagel condensation of 1,3-cyclohexadiones with various β-formyl-esters, followed by lactonization in the presence of nano ZnO (20 mol %). Moderate to high yields and readily available cheap starting materials are the key features of the present method  

    One-pot synthesis of ZnO nanoparticles and submicron-aggregates for dye-sensitized solar cells

    , Article Materials Letters ; Volume 139 , January , 2015 , Pages 433-436 ; 0167577X (ISSN) Rostami, P ; Nemati, A ; Malekshahi Byranvand, M ; Mohammadpour, R ; Faridi, H ; Sharif University of Technology
    Elsevier  2015
    Abstract
    ZnO nanoparticles (NPs) and submicron aggregates (SMAs) were synthesized via a simple precipitation method by changing the amount of zinc acetate di-hydrate in absolute ethanol and synthesis time. Synthesized NPs and SMAs were characterized by FE-SEM, EDS, XRD, PL, and DRS and were used to fabricate dye-sensitized solar cells (DSSCs). The SMAs synthesized at moderate concentration (0.022 M) and with poly-dispersed distribution of the aggregates showed lower density of deep localized trap states as well as enhanced scattering features in comparison to NP-based electrode. As a result, power conversion efficiency (η) of about 2.56% with improved current density (Jsc) of 8.51 mA/cm2 were... 

    The effect of nanoparticles on the mass transfer in Liquid–Liquid extraction

    , Article Chemical Engineering Communications ; Volume 202, Issue 5 , Sep , 2015 , Pages 600-605 ; 00986445 (ISSN) Mirzazadeh Ghanadi, A ; Heydari Nasab, A ; Bastani, D ; Seife Kordi, A. A ; Sharif University of Technology
    Taylor and Francis Ltd  2015
    Abstract
    This article investigates the effect of nanoparticles on mass transfer in the liquid–liquid extraction for the chemical system of n-butanol–succinic acid–water. For this purpose, nanofluids containing various concentrations of ZnO, carbon nanotubes (CNT), and TiO2 nanoparticles in water, as base fluid, were prepared. To examine the flow mode effect on mass transfer rate, different fluid modes including dropping and jetting were employed in the process. Results show that mass transfer rate enhancement depends on the kinds and the concentration of nanoparticles and the modes of flow. It was observed that after adding nanoparticles, the mass transfer rate significantly increases up to two-fold... 

    Preparation of ZnO nanoparticles/Ag nanowires nanocomposites as plasmonic photocatalysts and investigation of the effect of concentration and diameter size of Ag nanowires on their photocatalytic performance

    , Article Journal of Alloys and Compounds ; Volume 664 , 2016 , Pages 707-714 ; 09258388 (ISSN) Khademalrasool, M ; Farbod, M ; Iraji Zad, A ; Sharif University of Technology
    Elsevier Ltd 
    Abstract
    In this work the plasmonic photocatalytic activity of ZnO/noble metals nanocomposites has been investigated. Ag nanowires and Au nanospheres were prepared and mixed with ZnO in order to prepare the nanocomposites. It was demonstrated that the composites containing the plasmonic Ag nanowires and ZnO nanoparticles showed a significant photocatalytic activity enhancement compared to the pure ZnO in decomposition of methylene blue (MB). By investigation of mechanisms governing the performance of plasmonic photocatalysts, it was found that the photocatalytic activity enhancement can be attributed to the energy transfer from Ag nanowires to the ZnO nanoparticles induced by the surface plasmonic... 

    Dispute in photocatalytic and photoluminescence behavior in ZnO/graphene oxide core-shell nanoparticles

    , Article Materials Letters ; Volume 240 , 2019 , Pages 117-120 ; 0167577X (ISSN) Haghshenas, S. S. P ; Nemati, A ; Simchi, A ; Kim, C. U ; Sharif University of Technology
    Elsevier B.V  2019
    Abstract
    ZnO/graphene oxide core-shell nanoparticles (ZGNPs) were prepared by via in-situ chemical synthesis and electrolysis. This report addresses the disagreement in the photocatalytic and photoluminescence behavior in this system. XRD, Raman, HRTEM, PL and UV–Vis were able to confirm ZnO nanoparticles and core-shell structures formation at various temperatures. A little shift was observed in Raman for ZGNPs after conjugating. PL showed a few peaks that were not related to the graphene, which depends on the synthesis route and defects. After conjugating between ZnO and Graphene, two mechanisms are suggested. The first is band structure modification in the boundary of core and shell. The second one... 

    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
    Abstract
    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... 

    Studies of Ponceau 4R food colorant and zinc oxide nanoparticles containing it interactions with DNA and evaluation of their antimicrobial activity

    , Article Journal of Food Processing and Preservation ; Volume 46, Issue 2 , 2022 ; 01458892 (ISSN) Zangeneh Monfared, F ; Shahabadi, N ; Mahmoudi Hashemi, M ; Meibodi, F. S ; Mirjafari, Z ; Sharif University of Technology
    John Wiley and Sons Inc  2022
    Abstract
    The current study describes design and synthesis of silica-coated zinc oxide nanoparticles containing Ponceau 4R food colorant (named as ZnO@SiO2@APTMS/P4R). The interactions of Ponceau 4R and ZnO@SiO2@APTMS/P4R with calf thymus-DNA were investigated It should be noted that the competitive binding experiment revealed that both Ponceau 4R and ZnO@SiO2@APTMS/P4R could release Hoechst 33258. As inferred from the results the binding of the Ponceau 4R and ZnO@SiO2@APTMS/P4R with DNA were surface binding, mainly due to groove binding. Furthermore, antibacterial properties of ZnO, Ponceau 4R and ZnO@SiO2@APTMS/P4R samples against gram-positive bacteria and gram-negative bacteria were examined and... 

    Photocatalytic activity of TiO 2-capped ZnO nanoparticles

    , Article Journal of Materials Science: Materials in Electronics ; Volume 23, Issue 2 , 2012 , Pages 361-369 ; 09574522 (ISSN) Lak, A ; Simchi, A ; Nemati, Z. A ; Sharif University of Technology
    Abstract
    Using a combined hydrothermal and sol-gel route, TiO 2 -capped ZnO nanoparticles with an average size of 60 nm were prepared. The titania shell was amorphous with a thickness of ∼10 nm. Formation of Zn 2TiO 4 phase at higher calcination temperature was noticed. Effects of Ti/Zn molar ratio and coating time on the thickness of TiO 2 shell and the photoactivity of the particles for decolorization of Methylene Blue (MB) under UV lamp irradiation (3 mW/cm 2) were investigated. The nanoparticles were characterized by X-ray diffraction, transmission electron microscopy, fourier-transform infrared spectrometry (FTIR), diffuse reflectance spectroscopy (DLS), and atomic absorption spectroscopy.... 

    Effects of initial precursor and microwave irradiation on step-by-step synthesis of zinc oxide nano-architectures

    , Article Materials Letters ; Volume 67, Issue 1 , 2012 , Pages 342-345 ; 0167577X (ISSN) Kajbafvala, A ; Samberg, J. P ; Ghorbani, H ; Kajbafvala, E ; Sadrnezhaad, S. K ; Sharif University of Technology
    Abstract
    ZnO nano-architectures were produced with the aid of a fast, simple and low cost microwave-assisted synthesis method. Solid semispherical ZnO nanoparticles on the order of 600 nm in diameter along with rice-like ZnO nanorods 95 nm thick were produced from butanol, triethanolamine (TEA), and zinc acetate dihydrate. Solid spherical ZnO nano-architectures with an average diameter of 250 nm were produced from the same starting materials in addition to NaOH. X-ray diffraction, scanning electron microscopy, and transmission electron microscopy were used to characterize the ZnO nano-architectures as well as the precursor. This method is cheap, fast and simple; capable of producing large quantities... 

    Photocatalytic reduction of graphene oxides hybridized by ZnO nanoparticles in ethanol

    , Article Carbon ; Volume 49, Issue 1 , January , 2011 , Pages 11-18 ; 00086223 (ISSN) Akhavan, O ; Sharif University of Technology
    2011
    Abstract
    Graphene oxide platelets synthesized by using a chemical exfoliation method were dispersed in a suspension of ZnO nanoparticles to fabricate ZnO/graphene oxide composite. Formation of graphene oxide platelets (with average thickness of ∼0.8 nm) hybridized by ZnO nanoparticles (with average diameter of ∼20 nm) was investigated. The 2D band in Raman spectrum confirmed formation of single-layer graphene oxides. The gradual photocatalytic reduction of the graphene oxide sheets in the ZnO/graphene oxide suspension of ethanol was studied by using X-ray photoelectron spectroscopy for different ultra violet (UV)-visible irradiation times. After 2 h irradiation, the relative concentration of the... 

    Photocatalytic activity of ZnO nanoparticles prepared via submerged arc discharge method

    , Article Applied Physics A: Materials Science and Processing ; Volume 100, Issue 4 , September , 2010 , Pages 1097-1102 ; 09478396 (ISSN) Ashkarran, A. A ; Iraji Zad, A ; Mahdavi, S. M ; Ahadian, M. M ; Sharif University of Technology
    2010
    Abstract
    ZnO nanostructures were synthesized through arc discharge of zinc electrodes in deionized (DI) water. X-ray diffraction (XRD) analysis of the prepared nanostructures indicates formation of crystalline ZnO of hexagonal lattice structures. Transmission electron microscopy (TEM) images illustrate rod-like as well as semi spherical ZnO nanoparticles with 15-20 nm diameter range, which were formed during the discharge process with 5 A arc current. The average particle size was found to increase with the increasing arc current. X-ray photoelectron spectroscopy (XPS) analysis confirms formation of ZnO at the surface of the nanoparticles. Surface area of the sample prepared at 5 A arc current,... 

    Microstructural and electrical properties of varistors prepared from coated ZnO nanopowders

    , Article Journal of Materials Science: Materials in Electronics ; Volume 21, Issue 6 , June , 2010 , Pages 571-577 ; 09574522 (ISSN) Shojaee, S. A ; Maleki Shahraki, M ; Faghihi Sani, M. A ; Nemati, A ; Yousefi, A ; Sharif University of Technology
    2010
    Abstract
    This paper describes a solution-based technique for fabrication of varistor grade composite nanopowders. The method consists of coating major varistor dopants on the surface of the ZnO nanoparticles. As a result, a homogenous mixture of dopants and ZnO nanoparticles will be achieved. TEM results indicated that a composite layer of dopants with the average particle size of 9 nm on the surface of ZnO nanoparticles has been successfully prepared. Sintering of the coated powders was performed in temperatures as low as 850 °C and final specimens with average particle size of 900 nm and density of 98.5% were achieved. In comparison to conventional mixing, varistors prepared from coated nanopowders... 

    Effect of ZnO nanoparticles coating layers on top of ZnO nanowires for morphological, optical, and photovoltaic properties of dye-sensitized solar cells

    , Article Micromachines ; Volume 10, Issue 12 , 2019 ; 2072666X (ISSN) Saleem, M ; Farooq, W. A ; Iftikhar Khan, M ; Niaz Akhtar, M ; Rehman, S. U ; Ahmad, N ; Khalid, M ; Atif, M ; AlMutairi, M. A ; Irfan, M ; Sharif University of Technology
    MDPI AG  2019
    Abstract
    This paper reports on the synthesis of ZnO nanowires (NWs), as well asthe compound nanostructures of nanoparticles (NPs) and nanowires (NWs+NPs) with different coating layers of NPs on the top of NWs and their integration in dye-sensitized solar cells (DSSCs). In compound nanostructures, NWs offer direct electrical pathways for fast electron transfer, and the NPs of ZnOdispread and fill the interstices between the NWs of ZnO, offering a huge surface area for enough dye anchoring and promoting light harvesting. A significant photocurrent density of 2.64mA/cm2 and energy conversion efficiency of 1.43% was obtained with NWs-based DSSCs. The total solar-to-electric energy conversion efficiency...