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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
    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
    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... 

    Hydrothermal preparation of TiO2-ZnO nano core-shell structure with quantum size effect

    , Article AIP Conference Proceedings, 12 May 2011 through 15 May 2011 ; Volume 1400 , May , 2011 , Pages 425-428 ; 0094243X (ISSN) ; 9780735409712 (ISBN) Asl, S. K ; Rad, M. K ; Sadrnezhaad, S. K ; Sharif University of Technology
    Nano sized ZnO on TiO 2 spherical core shells were prepared by using hydrothermal method. The particle size of initial TiO 2 was around 20 nm, and the specific surface area was 50 m2/gr. Different ratios of TiO 2 and ZnO applied to synthesize core shell particle. X-ray diffraction (XRD) used to phase characterization and crystalline size, scanning electron microscopy (SEM) to morphology and microstructure investigations. S. Brunauer, P. H. Emmett and E. Teller method (BET) to find specific surface area, Diffusive UV-visible-NIR spectrometry to bang gap calculations. The results indicate that powders with a shell of zinc oxide in specific range have the quantum size effect. Titanium oxide and... 

    Growth of ZNO nanostructures on porous silicon and oxidized porous silicon substrates

    , Article Brazilian Journal of Physics ; Volume 41, Issue 2-3 , 2011 , Pages 113-117 ; 01039733 (ISSN) Rajabi, M ; Dariani, R. S ; Iraji Zad, A ; Sharif University of Technology
    We have investigated an oxidation of substrate effect on structural morphology of zinc oxide (ZnO) rods. ZnO rods are grown on porous silicon (PS) and on thermally oxidized porous silicon substrates by carbothermal reduction of ZnO powder through chemical vapour transport and condensation. Porous silicon is fabricated by electrochemical etching of silicon in hydrofluoric acid solution. The effects of substrates on morphology and structure of ZnO nanostructures have been studied. The morphology of substrates is studied by atomic force microscopy in contact mode. The texture coefficient of each sample is calculated from X-ray diffraction data that demonstrate random orientation of ZnO rods on... 

    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
    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... 

    Synthesis and characterization of ZnO/g-C3N4 hybrid nanofibers photocatalyst for the removal of organic pollutants from water

    , Article Iranian Journal of Physics Research ; Volume 20, Issue 2 , 2020 , Pages 273-280 Naseri, A ; Samadi, M ; Pourjavadi, A ; Moshfegh, A ; Sharif University of Technology
    Isfahan University of Technology  2020
    ZnO/gC 3 N 4 hybrid nanofibers containing different concentrations of gC 3 N 4 nanosheets were prepared using electrospinning technique; this was followed by annealing at 460 forC for one hour in a box furnace. Based on scanning electron microscopy (SEM) image analysis, the mean diameter of the nanofibers was measured to be ~ 55 nm. Fourier transform infrared (FTIR) spectroscopy confirmed the presence of ZnO and gC 3 N 4 in the prepared nanofibers. The photocatalytic activity of the nanofibers was examined under UV photoirradiation, showing that the ZCN0.5 nanofibers containing 0.5 wt% of gC 3 N 4exhibited the highest performance, as compared to other photocatalysts. The observed improvement... 

    Effects of morphology on photocatalytic performance of Zinc oxide nanostructures synthesized by rapid microwave irradiation methods

    , Article Superlattices and Microstructures ; Volume 51, Issue 4 , 2012 , Pages 512-522 ; 07496036 (ISSN) Kajbafvala, A ; Ghorbani, H ; Paravar, A ; Samberg, J. P ; Kajbafvala, E ; Sadrnezhaad, S. K ; Sharif University of Technology
    In this study, two different chemical solution methods were used to synthesize Zinc oxide nanostructures via a simple and fast microwave assisted method. Afterwards, the photocatalytic performances of the produced ZnO powders were investigated using methylene blue (MB) photodegradation with UV lamp irradiation. The obtained ZnO nanostructures showed spherical and flower-like morphologies. The average crystallite size of the flower-like and spherical nanostructures were determined to be about 55 nm and 28 nm, respectively. X-ray diffraction (XRD), scanning electronic microscopy (SEM), Brunauer-Emmett-Teller (BET), room temperature photoluminescence (RT-PL) and UV-vis analysis were used for... 

    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
    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... 

    Sustainable superhydrophobic branched hierarchical ZnO nanowires: Stability and wettability phase diagram

    , Article Applied Surface Science ; Volume 561 , 2021 ; 01694332 (ISSN) Ebrahimi, M ; Bayat, A ; Rahemi Ardekani, S ; Saievar Iranizad, E ; Zaker Moshfegh, A ; Sharif University of Technology
    Elsevier B.V  2021
    Stability of Cassie-Baxter (CB) state is very critical in application of superhydrophobic surfaces. The most industrial applications of superhydrophobic surfaces are limited by the transition from the CB state to Wenzel (W) state. In this research, CB state stability of branched hierarchical ZnO nanowires (BH-ZnO NWs) was investigated as compared with ZnO nanowires (ZnO NWs) by using theoretical and experimental approaches. For this purpose, surface of the BH-ZnO NWs and ZnO NWs were modified by thin layers of methyltrimethoxysilane (MTMS). The MTMS thickness was optimized by varying NH4F (0, 5, 10, 20 μL) as used catalyst. The highest water contact angle (WCA) was measured at about 153 ± 3°... 

    Photo-degradation of organic dye by zinc oxide nanosystems with special defect structure: Effect of the morphology and annealing temperature [electronic resource]

    , Article Journal of Applied Catalysis A: General ; 22 February 2014, Volume 472, Pages 198–204 Shidpour, R. (Reza) ; Simchi, A. (Abdolreza) ; Ghanbari, Faegheh ; Vossoughi, M ; Sharif University of Technology
    The fabrication of strong photocatalysts applied to the degradation of organic pollutants is necessary in environmental applications. In a single-stage method, acetate precursor and poly vinyl pyrolydine are used to produce ZnO nanostructures with various morphologies in annealing temperatures ranging from 300 to 900 °C. The physical properties of the prepared nanostructures were characterized by SEM, TEM, XRD, BET, DRS, CHN analysis and PL spectroscopy. The SEM images exhibit a variety of the as-prepared hexagonal zinc oxides including wires, rods, particles and porous network of welded particles of ZnO nanoparticles. The results of the photocatalytic degradation of methylene blue as an... 

    Strain rate sensitivity, work hardening, and fracture behavior of an Al-Mg TiO2 nanocomposite prepared by friction stir processing [electronic resource]

    , Article Journal of Metallurgical and Materials Transactions A ; August 2014, Volume 45, Issue 9, P.4073-4088 Khodabakhshi, F ; Simchi, A. (Abdolreza) ; Kokabi, Amirhossein ; Nosko, Martin ; Svec, Peter ; Sharif University of Technology
    Annealed and wrought AA5052 aluminum alloy was subjected to friction stir processing (FSP) without and with 3 vol pct TiO2 nanoparticles. Microstructural studies by electron backscattered diffraction and transmission electron microscopy showed the formation of an ultra-fine-grained structure with fine distribution of TiO2 nanoparticles in the metal matrix. Nanometric Al3Ti and MgO particles were also observed, revealing in-situ solid-state reactions between Al and Mg with TiO2. Tensile testing at different strain rates determined that FSP decreased the strain rate sensitivity and work hardening of annealed Al-Mg alloy without and with TiO2 nanoparticles, while opposite results were obtained... 

    Nanosheet arrays of TiO2synthesized by one step conversion of ZnO nanosheets: Boosting of electron transport rate and application in dye solar cells

    , Article RSC Advances ; Vol. 4, issue. 85 , 2014 , pp. 45174-45179 ; ISSN: 20462069 Alimirsalari, S ; Tajabadi, F ; Salehkoutahi, S. M ; Ghahary, R ; Taghavinia, N ; Sharif University of Technology
    A TiO2replica of ZnO nanosheet films is synthesized using a chemical replacement process. ZnO nanosheets are grown by electrodeposition on fluorine doped tin oxide (FTO) films, and a dissolution/deposition process is used to convert the ZnO template into a TiO2replica. Electron microscopy shows the final TiO2structure follows the morphology of the initial ZnO template. X-ray diffraction and energy dispersive spectroscopy verify the total transformation of ZnO to TiO2. The as-synthesized TiO2sheets are amorphous and after annealing turn into the anatase phase. The film of TiO2nanosheets is used as the photoanode of a dye sensitized solar cell. Despite the low roughness factor of 100, a... 

    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
    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... 

    Optoelectronic properties of cauliflower like ZnO-ZnO nanorod/p-Si heterostructure

    , Article Solid-State Electronics ; Volume 80 , 2013 , Pages 33-37 ; 00381101 (ISSN) Rajabi, M ; Dariani, R. S ; Iraji Zad, A ; Zahedi, F ; Sharif University of Technology
    The cauliflower like ZnO nanostructures are grown on ZnO nanorods using spray pyrolysis method. First, ZnO nanorod arrays are grown on p-type silicon substrate without catalyst by chemical vapor transport and condensation method in a horizontal tube furnace. Afterwards, the cauliflower like ZnO nanostructures is deposited on top of the ZnO nanorod array. The PL spectra of cauliflower like ZnO nanostructures consist of UV emission bands around 387 nm and a visible emission at ∼440 nm. The current-voltage (I-V) measurement under dark and UV illumination condition are performed to study photodetection of the cauliflower like ZnO-ZnO nanorod/p-Si heterostructure. The experimental data of dark... 

    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
    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... 

    Direct production of dimethyl ether from synthesis gas utilizing a new bifunctional catalyst

    , Article 19th International Congress of Chemical and Process Engineering, CHISA 2010 and 7th European Congress of Chemical Engineering, ECCE-7, 28 August 2010 through 1 September 2010, Prague ; 2010 Khandan, N ; Kazemeini, M ; Aghaziarati, M ; Sharif University of Technology
    A series of bifunctional catalysts Cu-ZnO-ZrO 2/Al-modified H-Mordenite were prepared by co precipitating sedimentation method and were characterized. Active sites were dispersed well. The synthesis of dimethyl ether (DME) via direct CO hydrogenation was evaluated in a three-phase slurry reactor. Cu-ZnO-ZrO 2/Al-modified H-Mordenite was a suitable catalyst for the production of dimethyl ether from synthesis gas. The appropriate ratio of methanol synthesis catalyst (Cu-ZnO-ZrO 2) to methanol dehydration catalyst (Al-modified H Mordenite) was 2:1. In this condition, CO conversion and DME selectivity were ≈ 68% and 82%, respectively. This is an abstract of a paper presented at the 7th European... 

    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
    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,... 

    High efficiency and stable perovskite solar cell using zno/rgo qds as an electron transfer layer

    , Article Advanced Materials Interfaces ; Volume 3, Issue 11 , 2016 ; 21967350 (ISSN) Tavakoli, M. M ; Tavakoli, R ; Nourbakhsh, Z ; Waleed, A ; Virk, U. S ; Fan, Z ; Sharif University of Technology
    Wiley-VCH Verlag  2016
    Fabrication of organohalide perovskite materials on the top of ZnO nanoparticles (NPs) has some beneficial advantages such as room temperature processing; however, the perovskite is not stable on ZnO NPs layer during the annealing process. In fact, there are only a few reports about the fabrication of perovskite solar cells on ZnO NPs layer. Herein, the decomposition mechanism of CH3NH3PbI3 perovskite materials on ZnO is reported, and it is found that the perovskite film on the top of the ZnO layer is converted into PbI2 during the annealing process due to the existence of hydroxide groups on the surface of the ZnO NPs. Depending on the annealing temperature, the reaction rate and the... 

    Zeolitic imidazolate framework-derived Ag/C/ZnO for rapid reduction of organic pollutant

    , Article Journal of the Iranian Chemical Society ; Volume 16, Issue 5 , 2019 , Pages 1105-1111 ; 1735207X (ISSN) Falamarzi, M ; Akbarzadeh, E ; Gholami, M. R ; Sharif University of Technology
    Springer Verlag  2019
    One of the appealing usages of metal–organic frameworks is their application in manufacturing of metal oxide and metal oxide nanocomposites. In the present study, we used zeolitic imidazolate framework (ZIF-8) as precursor to prepare a new Ag/C/ZnO catalyst. The as-prepared samples were characterized using X-ray diffraction, Fourier-transform infrared, scanning electron microscopy and transmission electron microscopy analysis. Improved catalytic performance of as-prepared Ag/C/ZnO was confirmed by reduction of organic pollutants including p-nitrophenol, methylene blue and rhodamine-B in the presence of NaBH 4 in aqueous media. The synergistic effect between Ag and ZnO was proposed as the... 

    Hybrid adsorption–photocatalysis properties of quaternary magneto-plasmonic ZnO/MWCNTs nanocomposite for applying synergistic photocatalytic removal and membrane filtration in industrial wastewater treatment

    , Article Journal of Photochemistry and Photobiology A: Chemistry ; Volume 391 , 2020 Irani, E ; Amoli Diva, M ; Sharif University of Technology
    Elsevier B.V  2020
    A new multifunctional filtration membrane was prepared by twofold advantages of conventional polymeric-membrane as the supporting layer and magneto-plasmonic Ag-doped ZnO@Fe3O4/MWCNTs nanocomposite as the functional layer. Poly acrylic acid (PAA)-modified polyamide (PA) discs (PAA-PA) were applied to increase the hydrophilicity of prepared membrane and X-Ray diffraction (XRD) and scanning electron microscopy (SEM) techniques were used for characterization. The grafting yield of PAA in the pores and on the surface of PA was 17 wt.% and weigh difference between PAA-PA membrane before and after modifying with the photocatalyst was 8.7 mg. The amount of photocatalyst loading in the prepared...