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photocatalytic-property
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An Investigation on Photocatalytic Properties of Sol-Gel Produced TiO2-SiO2-Ni Nanocomposite Coatings
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Supervisor)
Abstract
Titania is one of the photocatalytic materials , but low quantum yield and relatively high band gap of TiO2 limited its applications.There are several ways to improve the photocatalytic properties of this material relied on narrowing the band gap,by doping TiO2 with other metals and oxides or increasing its specific surface area.In this work ,TiO2-SiO2-Ni coating have been made by sol-gel process and deposited on quartz substrate by using of dip-coating method .Effect of increasing Nickel content in nanocomposite and primary sol on crystalline structure,morphol ogy, photocatalytic properties and specific surface area have been investigated by means of X-Ray diffraction method, FT-IR, SEM,...
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) ; Mahdavi, S. M ; Taghavinia, N ; Azarian, A ; Sharif University of Technology
World Scientific Publishing Co. Pte Ltd
2008
Abstract
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...
Electric and Buckling Instabilities Effects on the Dynamics and Geometry of the Fibers in Electrospinning
, Ph.D. Dissertation Sharif University of Technology ; Iraji Zad, Azam (Supervisor) ; Ejtehadi, Mohammad Reza (Supervisor)
Abstract
Since previous models can not give a complete description for electrospinning electrical instability, using polymer solutions with diifferent properties, the aim of the existing thesis is to propose a new model that covers a range of materials from non-conducting to conducting and from viscous to elastic and also the initial jet’s tension. In addition, since the previous models have used large wave length approxiamtions, using accurate calculations we showed that the new model has better results for small wavelengths of about two times the jet’s radii. To compare the model to experimental results, we designed and made a proper setup to record the electrospinning process for a PEO solution...
Synthesis and Characterization of Electrospun N/S Doped ZnO and Investigation of their Applications in Dye Degradation
, M.Sc. Thesis Sharif University of Technology ; Poujavadi, Ali (Supervisor)
Abstract
In this research, the synthesis of the electrospum nano fiber doped zinc oxide and its photocatalyst usage was investigated. The band gap of the zinc oxide in the area of UV leads to deactivation of this material at the visible light. With due the attention to sunny weather in Iran and the fact that about 50 percentage of sunlight is visible light, producing and usage of catalyst materials actived at visible light is economical. Doping is one of the ways of activating ZnO at visible light, so in this research thiourea is used as the source of ZnO doping. The results of the expriments done at visible light and also spectrums of DRS, XPS and XRD prove that the doping is happened. Also, in this...
Synthesis, Characterization and Photocatalytic Application of Sol-gel Derived ZnO@CdS Coreshell Nanorods
, M.Sc. Thesis Sharif University of Technology ; Moshfegh, Alireza (Supervisor)
Abstract
Synthesis, characterization and photocatalytic applications of core-shell like ZnO@CdS nanorods have been studied in this research. The synthesis of core-shell like ZnO@CdS nanorods was carried out in three different steps. At first, ZnO seed layer was formed on glass substrate via sol-gel process under optimum conditions using absolute ethanol solution containing zinc acetate and a stabilizer ( either Monoethanolamine (MEA) or diethanolamine (DEA)). When MEA used as stabilizer, the optimum concentration of sol was found 0.2 M, while increasing the sol concentration caused the seed layer to be grown in a string-like structure. The RMS surface roughness of seed layer prepared by 0.2 M sol...
The Effect of Porosity on Photocatalytic Properties of TiO2 Nanocoating Fabricated By Sol-Gel
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Supervisor)
Abstract
This thesis is concerned with the synthesis and characterization of high porous Ti based on thin films and the effect of polymer agents on their photocatalytic properties. Ti films can demonstrate different properties like self -cleaning and treatment of broad range of aqueous pollutants when it is exposed to light of wavelength less than 400 nm. This is due to photocatalytic reaction occurring on film surface which results in film superhydrophilicity and the active oxygen species production. This active sites and radicals will cause oxidize organic pollutants and microbe adherent to the material surface.
In this study Ti thin films have been prepared by the sol-gel method from...
In this study Ti thin films have been prepared by the sol-gel method from...
Synthesis and Characterization of Nano-photocatalytic Metal Oxide / Graphene Using arc Discharge in Liquid
, M.Sc. Thesis Sharif University of Technology ; Iraji Zad, Azam (Supervisor) ; Ahadian, Mohammad Mahdi (Supervisor)
Abstract
In this thesis, graphene/titanium oxide and graphene/tungsten oxide composites were synthesized using arc discharge in liquid and their photocatalytic behavior was studied. Based on physical principles of the arc discharge in liquid, geometry of point-point was used for metallic Ti and W electrodes. TiO2 and WO3 nanoparticles and their nanocomposites with graphene and graphene oxide (GO) were studies using DLS, UV-vis, PL, ICP, FTIR, XRD, Raman and TEM characterization. The concentration of aqueous solution of Rhodamine B mixed with graphene/WO3 and GO/WO3 composites and WO3 nanoparticles under ultraviolet light was measured versus time and reached to 0.1, 0.6 and 0.6 of the initial value...
Fabrication and Characterization of ZnO Composites Nanofibers by Electrospinning Method for Photocatalytic Application
, Ph.D. Dissertation Sharif University of Technology ; Moshfegh, Ali Reza (Supervisor) ; Pourjavadi, Ali (Co-Advisor)
Abstract
In this research we focus on study and fabrication of ZnO composite nanofibers by electrospinning method for photocatalytic application. The most important challenges in the field of photocatalyst are photocatalytic activity under the visible light and efficiency enhancement. ZnO is a wide band gap semiconductor and it is not active under the visible light. In Iran, we have more than 300 sunny days in a year. Therefore fabrication and application of photocatalytic material with activity under the sun light that contained 40% of visible light is so vital in our country. In the first part of this project, ZnO-CNT nanofibers were fabricated and carbon doped in the crystal lattice of the ZnO....
Synthesis and Study of Photocatalytic Properties of g-C3N4/TiO2 Nanocomposite
, M.Sc. Thesis Sharif University of Technology ; Sadrnezhaad, Khatiboleslam (Supervisor)
Abstract
In this research, synthesis and characterization of photocatalytic properties of g-C3N4 / TiO2 nanocomposite was carried out. The target of research was to increase the photocatalytic properties of g-C3N4. So at first, g-C3N4 was synthesized from melamine precursor via thermal pyrolysis. Then, TiO2 nanoparticles were synthesized via sol – gel method. g-C3N4 / TiO2 nanocomposite with heterojunction structure was synthesized in one step by thermal pyrolysis of certain amounts of melamine precursor and TiO2 nanoparticles mixture in 550 ℃. Characterization of synthesized samples was carried out by XRD, FT-IR, UV-Vis, PL, BET, DLS and FE-SEM tests. Characterization results showed that g-C3N4,...
Electrochemical behavior of S-doped nanostructured TiO2 layer synthesized with PEO process for photocatalytic applications
, Article Advanced Materials Research ; Volume 829 , 2014 , Pages 487-491 ; ISSN: 10226680 ; ISBN: 9783037859070 ; Ghorbani, M ; Sharif University of Technology
Abstract
Sulfur doped and pure micro-nanoporous TiO2 film were synthesized with PEO method to produce a film with a high surface area for photocatalysis applications. The effect of applied voltage and electrolyte concentration on the microstructure and photocatalytic properties of the prepared layer were investigated via SEM, XRD, EIS and DRS studies. Electrochemical Impedance Spectroscopy (EIS) was carried out in order to determine the corrosion and electrochemical properties of the produced layer. It was found that although the barrier layer resistance decreases with the voltage, the layers porosity and consequently the surface area increases. Finally the XRD and DRS spectrums were correlated with...
Titania nanostructured coating for corrosion mitigation of stainless steel
, Article Protection of Metals and Physical Chemistry of Surfaces ; Vol. 50, issue. 3 , 2014 , p. 371-377 ; Sani, M. A. F ; Sadeghian, Z ; Ghasemi, H ; Sharif University of Technology
Abstract
Anatase nanostructured coating has been prepared on 316 L stainless steel by sol-gel dip coating. The topography of the coatings surface has been analyzed using atomic force microscopy. The anticorrosion performance of the coatings has been evaluated using polarization curves. Effects of calcination temperature, withdrawal speed and times of coating on corrosion protection have been studied. The results showed calcination temperature of 400°C and withdrawal speed of 10 cm/min are desirable conditions to achieve high corrosion protection of 316 L stainless steel in chloride containing environments. Coatings with 3 times exhibit better resistance against corrosion in 0.5 molar NaCl solutions....
Effect of iron oxide and silica doping on microstructure, bandgap and photocatalytic properties of titania by water-in-oil microemulsion technique
, Article Transactions of the Indian Ceramic Society ; Volume 70, Issue 4 , Jan , 2011 , Pages 227-232 ; 0371750X (ISSN) ; Nemati, A ; Zari, M. H ; Ahadi, K ; Sharif University of Technology
2011
Abstract
The microemulsion method was successfully used to prepare a series of TiO2, Fe oxide and SiO2 doped TiO2 nanoparticles at Fe/Ti atomic ratio of 10% and Si/Ti atomic ratio of 15%. The molar ratio of water to surfactant (W0) was 2. The samples were calcinated at 350°C. The structural features of TiO2, Fe oxide and SiO 2-TiO2 were investigated by XRD, UV-Visible spectroscopy, SEM and TEM. XRD data verified the formation of typical characteristic anatase form in all the prepared Fe and SiO2-doped TiO2 samples. In comparison with the pure TiO2, Fe oxide and SiO 2-TiO2 samples were relatively large in particle size, indicating that doping with Fe oxide and SiO2 can help in increasing the particle...
Nanoporous Ag2O photocatalysts based on copper terephthalate metal–organic frameworks
, Article Journal of Materials Science ; Volume 50, Issue 13 , 2015 , Pages 4536-4546 ; 00222461 (ISSN) ; Kamrani, S ; Tasviri, M ; Elahifard, M ; Gholami, M ; Sharif University of Technology
Kluwer Academic Publishers
2015
Abstract
We report the nanoporous Ag2O based on the copper terephthalate metal–organic frameworks (Ag2O/MOF) photocatalyst. Ag2O/MOF nanostructure was formed via oxygen treatment of Ag/MOF nanoparticles. The resulting Ag2O/MOF photocatalysts were characterised by various techniques. Results showed that the synthesised Ag2O/MOF nanocomposite exhibited dramatic separation of photoinduced electron/hole and excellent photodegradation activity under visible light irradiation. The degradation rate of acid blue 92 using Ag2O/MOF nanocomposite is found to be higher than that using pure MOF and Ag/MOF. It was divulged that the photodegradation rate is increased by oxygen treatment of Ag in Ag/MOF structure....
Investigation on Photocatalytic and Corrosion Properties of Titania-Graphene Nanocomposite Coated by Electrophoretic Method
, M.Sc. Thesis Sharif University of Technology ; Nemati, Ali (Supervisor) ; Sadeghian, Zahra (Supervisor)
Abstract
The main purpose of this research was functionalizing graphene, in order to achieve higher hydrophobicity, and producing nanocomposite of functionalized graphene and titanium dioxide by hydrothermal method, and sequently invastigation on photocatalytic properties of the powders and corrosion properties of EPD coated samples. Graphene oxide was synthesized by improved Hummers method and reduced and sequently was functionalized through the chemical process with hydrazine and octadecylamine respectively. Then the nanocomposite of functionalized graphene-titania was synthesized by use of titanium isopropoxide precursor and its photocatalytic properties were measured. The analysis of the...
Replacement of Pt with Graphene Derivatives in Counter Electrode of Dye-Sensitized Solar Cells
, M.Sc. Thesis Sharif University of Technology ; Mohammadi, Mohammad Reza (Supervisor) ; Askari, Masoud (Supervisor)
Abstract
Dye-Sensitized solar cells are the third generation of solar cells that have the potential to increase efficiency as much as solar cells of previous generations, along with lower prices. The cathode electrode of the pigmented solar cell as one of the essential components of the cell plays the role of accelerating the oxidation reaction reduction of the electrolyte. Platinum often is used as a catalyst layer. To reduce production costs and maintain cell viability, platinum should replace with other materials at a lower cost and higher electrochemical activity. Recently, carbon materials have been considered for the production of inexpensive solar cells with suitable performance. Among...
On the growth and photocatalytic activity of the vertically aligned ZnO nanorods grafted by CdS shells
, Article Applied Surface Science ; Volume 273 , July , 2013 , Pages 391-398 ; 01694332 (ISSN) ; Moradlou, O ; Bayati, M. R ; Nien, Y. T ; Moshfegh, A. Z ; Sharif University of Technology
2013
Abstract
We have studied systematically photocatalytic properties of the vertically aligned ZnO@CdS core-shell nanorods where the features were grown through a multistep procedure including sol-gel for the formation of ZnO seed layer, hydrothermal process to grow ZnO nanorods, and successive ion layer adsorption and reaction (SILAR) process to deposit CdS nanoshells onto the ZnO nanorods. Formation of the ZnO seed layer and vertically aligned ZnO nanorods (d ∼ 40 nm) with a hexagonal cross-section was confirmed by AFM and SEM imaging. Successful capping of ZnO nanorods with homogeneous CdS nanocrystallites (∼5 nm) was ascertained by HRTEM diffraction and imaging. Optical properties of the samples...
Investigation of the antibacterial and photocatalytic properties of the zeolitic nanosized AgBr/TiO 2 composites
, Article Materials Science in Semiconductor Processing ; Volume 15, Issue 1 , February , 2012 , Pages 73-79 ; 13698001 (ISSN) ; Elahifard, M. R ; Vatan Meidanshahi, R ; Ghasemi, S ; Haghighi, S ; Gholami, M. R ; Sharif University of Technology
2012
Abstract
Zeolite-based Ag/AgBr and Ag/AgBr/TiO 2 photocatalysts were prepared by sol-gel and deposition methods and were characterized. Their photocatalytic activities were evaluated by inactivation of Escherichia (E.) coli and the photodegradation of Acid Blue 92 and potassium permanganate. The composites containing Ag/AgBr showed the antibacterial activity in the dark by releasing Ag ions into the medium. The results for inactivation of E. coli indicated that Ag/AgBr/TiO 2 modified photocatalyst had better antibacterial activity than Ag/AgBr/zeolite, while zeolite and TiO 2/zeolite did not show any antibacterial activity under visible light and dark conditions. Photodecolarization rate was affected...
Comparative studies on Ag3PO4/BiPO4-metal-organic framework-graphene-based nanocomposites for photocatalysis application
, Article Applied Surface Science ; Volume 351 , October , 2015 , Pages 216-224 ; 01694332 (ISSN) ; Tasviri, M ; Rahimi, E ; Gholami, M. R ; Sharif University of Technology
Elsevier
2015
Abstract
For the first time, we report novel Ag3PO4/BiPO4 (AB)-graphene-based photocatalysts. The fabricated nanocomposites were characterized by various techniques. The photocatalytic properties of the prepared catalysts were evaluated by the photodegradation of Atrazine herbicide under both visible and UV light irradiation. Atrazine concentration was determined using the spectrophotometric method according to the Konig's reaction by monitoring the absorbance at 470 nm wavelength during the photodegradation process. Both degradation rate and efficiency using graphene (GR)-based nanocomposites are found to be much better than using pure AB. Atrazine photodegradation displayed that the AB supporting...
Corrosion protection of 1050 aluminium alloy using a smart self-cleaning TiO2 -CNT coating
,
Article
Surface and Coatings Technology
;
Volume 275
,
2015
,
Pages 224-231
;
02578972 (ISSN)
; Sadeghian, Z
; Nemati, A
; Mohammadi, S. P
;
Sharif University of Technology
Elsevier
2015
Abstract
Inclusion of carbon nanotubes (CNTs) into the titanium dioxide coating on 1050 aluminium alloy was studied with the aim at enhancing the corrosion resistance of the surface. Composite coatings with various contents of CNTs were prepared via the sol-gel method and dip coating. XRD and FTIR phase and structural evaluations showed the presence of anatase phase in all thin films. Concomitant enhanced corrosion behaviour in the presence of CNTs was resulted from polarization potentiodynamic test. Band-gap evaluation was performed using absorbance spectra of coatings and showed considerable decrease of band-gap energy in the presence of CNTs. Photocatalytic properties and hydrophilicity of...
Graphene nanomesh by ZnO nanorod photocatalysts
, Article ACS Nano ; Volume 4, Issue 7 , 2010 , Pages 4174-4180 ; 19360851 (ISSN) ; Sharif University of Technology
2010
Abstract
Local photodegradation of graphene oxide sheets at the tip of ZnO nanorods was used to achieve semiconducting graphene nanomeshes. The chemically exfoliated graphene oxide sheets, with a thickness of ∼0.9 nm, were deposited on quartz substrates. Vertically aligned ZnO nanorod arrays with diameters of 140 nm and lengths of <1 μm were grown on a glass substrate by using a hydrothermal method. The graphene oxide sheets were physically attached to the tip of the ZnO nanorods by assembling the sheets on the nanorods. UV-assisted photodegradation of the graphene oxide sheets (with dimension of ∼5 × 5 μm) at a contact place with the ZnO nanorods resulted in graphene nanomeshes with a pore size of...