Search for: titanium-dioxide
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    Synthesis of TiO2 nano powder by the sol-gel method and its use as a photocatalyst

    , Article Journal of the Iranian Chemical Society ; Volume 7, Issue SUPPL. 1 , 2010 , Pages S154-S160 ; 1735207X (ISSN) Karami, A ; Sharif University of Technology
    In this work the titanium dioxide powder was prepared by the optimized and simple Sol-Gel method and then characterized. The gelling pH was set to values of 3 (TiO2-A), 7 (TiO2-N) and 9 (TiO2-B) to observe the effect on the properties of the material. In these three cases nanoparticulated materials were obtained with particle sizes between 10nm and 20nm. The larger surface areas were obtained at pH 3, which is several times larger than the others. Furthermore, with the gelling condition pH 3, it was possible to synthesize pure anatase phase titania. Some preliminary results on the test of the photocatalytic activity of the synthesized materials in the reduction of nitric oxide are presented.... 

    Horseradish peroxidase immobilization on amine functionalized carbon nanotubes: direct electrochemistry and bioelectrocatalysis

    , Article Progress in Reaction Kinetics and Mechanism ; Volume 37, Number 2 , 2012 , pp. 161-172 Tasviri, M. (Mahboubeh) ; Ghourchian, H. (Hedayatollah) ; Gholami, M. R. (Mohammad Reza) ; Rafieepour, H. A. (Hossain Ali) ; Sharif University of Technology
    Horseradish peroxidase (HRP) was successfully immobilized on amine functionalized TiO2-coated multiwalled carbon nanotubes (NH2 – TiO2 – CNTs) by a convenient and efficient method. Electrochemical impedance spectroscopy, cyclic voltammetry and amperometry were applied to characterize the HRP/NH2 – TiO2 – CNT nano-composite. These techniques showed that the NH2 – TiO2 – CNTs greatly enhance the electron transfer between HRP and the modified electrode. Owing to the redox reaction of the electroactive centre of HRP, the HRP = NH2 – TiO2 – CNTs modified electrode exhibited a pair of quasi-reversible peaks with a peak-to-peak separation (ΔEp) of 70.6 mV and a formal potential (E 0′) of 367.65 mV... 

    Electrophoretic deposition of titanium dioxide nano-powders films in isopropanol as a solvent

    , Article International Journal of Modern Physics B ; Volume 22, Issue 18-19 , 2008 , Pages 2989-2994 ; 02179792 (ISSN) Ghorbani, M ; Roushan Afshar, M ; Sharif University of Technology
    World Scientific Publishing Co. Pte Ltd  2008
    In this study, titanium dioxide nano powders were electrophoretically deposited on the stainless steel in Isopropanol and Triethanolamine as a solvent and dispersant, respectively. The effects of deposition parameters including deposition voltage (5 to 20 V) and deposition time (5 to 60 s) on the microstructure and surface topography were examined by scanning electron microscope (SEM) and scanning probe microscope (SPM), respectively. In addition, the effects of these deposition parameters on packing density were investigated. This research revealed that substrate surface is fully covered with increasing deposition voltage and deposition time. Therefore packing density of deposited films is... 

    Growth of TiO2 nanoparticles by pulsed laser ablation (PLA) in liquid media and study of photocatalytic properties

    , Article International Journal of Modern Physics B ; Volume 22, Issue 18-19 , 2008 , Pages 3193-3200 ; 02179792 (ISSN) Shadmehr, S ; Mahdavi, S. M ; Taghavinia, N ; Azarian, A ; Sharif University of Technology
    World Scientific Publishing Co. Pte Ltd  2008
    We synthesized TiO2 nanoparticles by pulsed laser ablation of titanium target immersed in an aqueous solution of surfactant sodium dodecyl sulfate (SDS) or deionized water. The surfactant concentration dependence on size of TiO2 nanoparticles was investigated. The maximum amount of nanoparticles (with mean size of 40 nm in diameter) was obtained in an aqueous solution of 0.001 M SDS. We have also studied the effect of laser wavelength on growth of TiO2 nanoparticles. UV/visible spectroscopy and Scanning Electron Microscopy observations were employed for characterization of optical properties and particle sizes respectively. As TiO2 is a famous photocatalyst, we have also done photocatalytic... 

    Preparation and Characterization of Sol-Gel Derived Mesoporous TiO2 Nanostructured by Copolymer Templated

    , M.Sc. Thesis Sharif University of Technology Mozaffari, Naeimeh (Author) ; Mohammadi, Mohammad Reza (Supervisor) ; Faghihi Sani, Mohammad Ali (Supervisor)
    In recent years, mesoporous nanocrystalline TiO2 films have been regarded extensively. This kind of materials due to having unique surface area, structural and bulk properties, is used in many technological applications. In this work, a stable TiO2 sol was prepared using F127 Copolymer template and evaporation induced self-assembly method (EISA). The mesoporous TiO2 powders and thin films were then prepared. The as-deposited thin films were aged under five different conditions for 72h. Finally the samples were heat treated at 350°C, 400°C and 450°C. N2 adsorption/desorption results verified formation of mesoporous structure. Moreover, x-Ray diffraction patterns exhibited that the synthesized... 

    Preparation of Mg-doped TiO2 Nanoparticles for Dye-sensitized Solar Cell Applications

    , M.Sc. Thesis Sharif University of Technology Safaee, Mahtab (Author) ; Mohammadi, Mohammad Reza (Supervisor)
    Dye-sensitized solar cell (DSSCS) is the third-generation of solar cells based on semiconductors formed between a photo sensitized anode and counter cathode which make a photo electrochemical system. They haven’t been commercially marketed due to their lower efficiency than the previous generations. In order to achieve the higher efficiency, the electron injection and light absorption must be increased. One way to increase electron injection is doping the semiconductor with an external ion to reduce lattice band gap. In this work, we made powder and Nano-structured film of titanium dioxide doped with various molar ratios of Mg by the sol-gel process. The effect of Mg:Ti molar ratio on... 

    Preparation of Ag-doped TiO2 Nanostructured Films for Dye-Sensitized Solar Cells Applications

    , M.Sc. Thesis Sharif University of Technology Rahnejat, Bibi (Author) ; Mohammadi, Mohammad Reza (Supervisor)
    Dye-sensitized solar cells (DSSCs) have been intensively studied duringthe last decade as a promising third solar cellgeneration due to their potential low-cost manufacturingprocess. DSSCsare based on a semiconductor (i.e., TiO2), formed between a photo-sensitized anode and an electrolyte. In order to reach high conversion efficiencies, it isimportant to increase the electron injection and opticalabsorption. One promising solution to increase the electroninjection is to decrease the large band gap of TiO2 bydoping a foreign ion into TiO2 lattice.
    In the present study, Ag- doped TiO2 powders and films with different Ag:Ti molar ratios are reported. The effect of dopant at.%, annealing... 

    Deposition of CdS on Nanostructured and Mesoporous TiO2 Film for Solar Cell Application

    , M.Sc. Thesis Sharif University of Technology Moayeri, Vahid (Author) ; Mohammadi, Mohammad Reza (Supervisor)
    In this project, The cadmium sulfide nanoparticles were formed on a nanostructured and meso-porous titanium dioxide layer and its properties were characterized. Deposition process of titanium dioxide and cadmium sulfide has been performed respectively in one stage and two stages of dipcoating. In order to probing effects of temperature and dipcoating time, samples have been prepared in various times and temperatures. Also, some of the samples have been annealed. Thickness of titanium dioxide and cadmium sulfide coatings were approximately measured 1 μm and between 3-5 μm, respectively. As expected, XRD results disclosed that cadmium sulfide and titanium dioxide were formed in the form of... 

    Synthesis and Characterization of Electrophoretic Deposited One- Imensional Nano Structured Titania

    , M.Sc. Thesis Sharif University of Technology Ordikhani, Farideh (Author) ; Mohammadi, Mohammad Reza (Supervisor) ; Khomamizadeh, Farzad (Supervisor)
    Recent studies have indicated that one-dimensional titanium dioxide (TiO2) shows excellent properties in comparison to other forms of TiO2 materials in photocatalysis, sensing, self-cleaning coating and photovoltaic applications. In this project TiO2 nanorods were grown in polycarbonate template, with pore diameter of 200 nm, by solelectrophoretic deposition method. Firstly, properties of TiO2 sol were investigated. The average particle size of TiO2 (measured by zeta sizer instrument) was 17 nm and the zeta potential was around 45 mV, which confirmed good stability of the sol against aging. Moreover, FTIR analysis showed that a full conversion of precursor (titanium isopropoxide) was... 

    The study of growth and coagulation of titania nanoparticles by chemical vapor synthesis

    , Article Journal of Nuclear Science and Technology ; No.53 , 2010 , pp. 20-29 Rahiminezhad-Soltani, M ; Saberyan, K ; Shahri, F ; Simchi, A. (Abdolreza) ; Sharif Univesity of Technology
    Chemical Vapor Synthesis route was used for synthesis of titanium dioxide (TiO2) nanoparticles in hot-walled reactor at 800degreeC using TiCl4 as precursor. The effect of processing parameters e.g., temperature and amount of precursor on phase structure, size, purity, coagulation and agglomeration of nanoparticles were investigated in this respect. Also, the H2O effects on the size, crystallinity, phase transformation and purity of nanoparticles were studied. Comprehensive experimental observations were confirmed by transmission electron microscopy, X-ray diffraction analysis and thermal gravimetric-differential thermal analysis results. The obtained results showed that by increasing the... 

    Highly efficient hydroxyapatite/TiO2 composites covered by silver halides as E. coli disinfectant under visible light and dark media

    , Article Photochemical and Photobiological Sciences ; Volume 12, Issue 10 , October , 2013 , Pages 1787-1794 Azimzadehirani, M ; Elahifard, M ; Haghighi, S ; Gholami, M. R. (Mohammad Reza) ; Sharif University of Technology
    TiO2-based photocatalysts are seen as the most common agents for the photodegradation of bacteria. In this study, AgCl/TiO2, hydroxyapatite(Hp)/AgCl/TiO2, AgI/TiO2, and Hp/AgI/TiO2 were prepared by the deposition-precipitation method on P25 TiO2 nanoparticles and were characterized by XRD, SEM, FT-IR, EDX and BET methods. The prepared composites showed high efficiency for the inactivation of Escherichia coli (E. coli) bacteria under visible light and in dark media with different catalyst amounts of 12 and 24 mg, respectively. In less than 30 min, AgI/TiO2, prepared by the combination of cationic surfactant and PVPI2, disinfected 1 × 10(7) colony-forming units of E. coli completely. However,... 

    Evaluation of the photo-catalytic degradation of pyrene using fe-doped tio2 in presence of UV

    , Article Desalination and Water Treatment ; Volume 169 , 2019 , Pages 232-240 ; 19443994 (ISSN) Khodadadi Saloot, M ; Borghei, S. M ; Haji Seyed Mohammad Shirazi, R ; Sharif University of Technology
    Desalination Publications  2019
    The oil-based compounds are widely used in modern human life, and the accidental release or leakage of these compounds is led to water and soil pollution and creates many problems for the environment. The purpose of this study was to determine the efficiency of photo-catalytic degradation of pyrene using Fe-doped TiO2 in the presence of UV. This experimental study was carried out at laboratory scale in a 2 L pilot reactor. The nanoparticle was synthesized by the sol-gel method. Pyrene degradation was investigated under different conditions of pH, reaction time, nanoparticle concentration and pollutant concentration. For the statistical analysis, SPSS V.16 software and one-way analysis of... 

    Mechanical modeling of silk fibroin/TiO2 and silk fibroin/fluoridated TiO2 nanocomposite scaffolds for bone tissue engineering

    , Article Iranian Polymer Journal (English Edition) ; Volume 29, Issue 3 , February , 2020 , Pages 219-224 Johari, N ; Madaah Hosseini, H. R ; Samadikuchaksaraei, A ; Sharif University of Technology
    Springer  2020
    Biocompatible and biodegradable three-dimensional scaffolds are commonly porous which serve to provide suitable microenvironments for mechanical supporting and optimal cell growth. Silk fibroin (SF) is a natural and biomedical polymer with appropriate and improvable mechanical properties. Making a composite with a bioceramicas reinforcement is a general strategy to prepare a scaffold for hard tissue engineering applications. In the present study, SF was separately combined with titanium dioxide (TiO2) and fluoridated titanium dioxide nanoparticles (TiO2-F) as bioceramic reinforcements for bone tissue engineering purposes. At the first step, SF was extracted from Bombyx mori cocoons. Then,... 

    Enhanced Electronic Properties in Mesoporous TiO2 Via Passivation Treatment in Perovskite Solar Cells

    , M.Sc. Thesis Sharif University of Technology Azadi, Moloud (Author) ; Mohammadi, Mohammad Reza (Supervisor)
    Perovskite solar cells are the new generation of solar cells, and are mainly introduced in two types of structures.1) planer and 2) mesoscopic structure. The difference between these two structures derives from the absence of mesoporous layer in the planer structures. The mesoporous layer acts as an electron transporting layer, and is mainly a titanium dioxide semiconductor. To apply the mesoporous layer, the preparation of the TiO2 paste is needed.The synthesis of titanium dioxide nanopowder for the preparation of TiO2 paste requires high temperature heat treatment and is not desirable in terms of energy consumption.Another weakness of this layer is the presence of surface defects, which... 

    TiO2 Production by Acid Leaching of Upgraded Titanium Slag

    , M.Sc. Thesis Sharif University of Technology Taherkhani, Omid (Author) ; Askari, Masoud (Supervisor)
    In Iran, titanium dioxide is still not produced and imports of titanium dioxide are required by various industries, including dyeing, electrodeposition, plastics and Therefore, according to the Ministry of Industries and Mines objectives, to obtain the technology of extraction Ti and TiO2, a research was carried out on titanomagnetite concentrate, extracted from the minerals of the plancher titanumitent and low-grade kahnoj. In this research, titanium dioxide is produced by sulfate method. Solid state recovery and magnetic separation were used to isolate titanium and iron. The dissolution process was then performed to achieve maximum dissolution. At this stage, the effects of temperature,... 

    Synthesizing One-Dimensional TiO2 Nanostructure for Dye-Sensitized Solar Cell Application

    , M.Sc. Thesis Sharif University of Technology Mojaddami, Majdoddin (Author) ; Madaah Hosseini, Hamid Reza (Supervisor) ; Mohammadi, Mohammad Reza (Supervisor)
    Over the past several years, TiO2 has become a focus of considerable researches as it possesses unique optical, catalytic and electrical properties in different applications such as sensors, water purification and dye-sensitized solar cells (DSSC). The goal of this research was synthesis of 1-Dimentional TiO2 nanostructure with suitable properties for DSSC applications. Two different TiO2 powders including micron-size anatase and mesoporous powders (produced from reaction of TiC and HNO3) along with KOH or NaOH were employed in hydrothermal process. The process was performed in two different containers including autoclave and balloon-shaped flask. The products were characterized by X-Ray... 

    Synthesis and characterization of poly(L-lactide)-block-poly(ε-caprolactone)-grafted titanium dioxide nanoparticles via ring-opening in situ grafting polymerization

    , Article Polymer Composites ; Volume 42, Issue 8 , 2021 , Pages 3722-3731 ; 02728397 (ISSN) Ebrahimi, H ; Sharif, F ; Ramezani Saadat Abadi, A ; Sharif University of Technology
    John Wiley and Sons Inc  2021
    The synthesis of nanocomposites via in situ grafting polymerization due to its ability to produce polymeric materials with promising microscopic and macroscopic characteristics is becoming very attractive. In this paper, different poly(L-Lactide)-block-poly(ε-caprolactone) (PLLA-b-PCL) copolymers were in situ synthesized in the presence of modified titanium dioxide (TiO2) nanoparticles (mTNP) as the initiator and stannous octoate as the catalyst. The surface of TiO2 was modified by grafting aminopropyl trimethoxy silane to improve initiator efficiency. Copolymers with 90/10, 70/30, and 50/50 mass ratio of L-lactide/ ε-caprolactone and 5 wt% of mTNP (proportional to ε-caprolactone) were... 

    Carrageenan-Based functional films integrated with cuo-doped titanium nanotubes for active food-packaging applications

    , Article ACS Sustainable Chemistry and Engineering ; Volume 9, Issue 28 , 2021 , Pages 9300-9307 ; 21680485 (ISSN) Ezati, P ; Riahi, Z ; Rhim, J. W ; Sharif University of Technology
    American Chemical Society  2021
    A titanium dioxide nanotube (TNT) and CuO-doped TNT (TNT-CuO) were synthesized using a hydrothermal method and incorporated into carrageenan-based films. The SEM results confirmed the formation of uniform nanocomposite films. The addition of nanoparticles imparted UV-blocking properties to the carrageenan film and increased the mechanical strength, surface hydrophobicity, and water vapor barrier properties. The modified TiO2 (TNT and TNT-CuO)-incorporated carrageenan films showed significantly higher antibacterial activity than the TiO2-added film under visible light. Bananas packaged with the neat carrageenan and TiO2-added films were degraded considerably after 12 days of storage at 20 °C.... 

    Synergy of titanium dioxide nanotubes and polyurethane properties for bypass graft application: Excellent flexibility and biocompatibility

    , Article Materials and Design ; Volume 215 , 2022 ; 02641275 (ISSN) Kianpour, G ; Bagheri, R ; Pourjavadi, A ; Ghanbari, H ; Sharif University of Technology
    Elsevier Ltd  2022
    A flexible, porous and biocompatible titanium dioxide nanotubes (TNT) - polyurethane (PU) film has been produced as a new scaffold for artificial vascular grafts. Synergistic improvements in the properties of vertical TNT and PU was reached, including enhancements in their biocompatibility, mechanical strength, flexibility and porosity. Open-ended (OE) TNT-PU and close-ended (CE) TNT-PU films were synthesized and their mechanical and biological properties were compared with their pure PU counterparts. TNT were attached to PU with a new strategy. The resulting flexible structure was hydrophilic and super hydrophilic in OE-TNT-PU and CE-TNT-PU scaffolds, respectively. The gas leakage during... 

    Hydrophilicity and AFM Based Surface Statistical Analysis of SiO2/TiO2/Glass Bilayer

    , M.Sc. Thesis Sharif University of Technology Daryaei, Ebrahim (Author) ; Moshfegh, Alireza (Supervisor) ; Jafari, Golamreza (Supervisor)
    Titanium dioxide (TiO2) is important because of wide applications such as self cleaning surfaces and using in photoelectrochemical cells .Recent researches have shown that addition of silicon dioxide into TiO2 increases hydrophilicity of SiO2-TiO2 and improves surface properties. Until now a little research has been done on the double layer TiO2/SiO2 system; therefore, this system is suitable for studying. In general this thesis consists of theoretical and experimental parts .In the experimental part, multilayer systems of SiO2/TiO2/Glass have been selected (thickness of SiO2 is 20 nm) and surface morphology and hydrophilicity have been investigated by Atomic Force Microscopy (AFM) and...