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titanium-oxide
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The effect of layer number on the nanostructural ternary mixed oxide containing Ti, Ru and Ir on titanium
, Article Advanced Materials Research ; Vol. 829 , 2014 , pp. 638-642 ; Ghorbani, M ; Sharif University of Technology
Abstract
Titanium anodes coated with noble metal oxides are widely used in chlorate industry. In fact, these anodes are dimensionally stable. In this article, the electrochemical characteristics of the ternary oxide coating created by sol-gel on titanium, which consisted of Ti, Ru and Ir, were investigated in the number of different layers. The electrochemical properties of anodes, morphology of samples, and phase analysis were investigated respectively by cyclic voltammetry and polarization measurements, Field Emission Scanning Electron Microscope (FESEM) and XRD. The result indicated that the application of the more layer number increases the rate of chlorine evolution. Also, The morphology of the...
Preparation and electrochemical performances of nanoporous/cracked cobalt oxide layer for supercapacitors
, Article Applied Physics A: Materials Science and Processing ; Vol. 117, issue. 4 , 2014 , pp. 2087-2094 ; ISSN: 09478396 ; Faraji, M ; Sharif University of Technology
Abstract
Nanoporous/cracked structures of cobalt oxide (Co3O4) electrodes were successfully fabricated by electroplating of zinc–cobalt onto previously formed TiO2 nanotubes by anodizing of titanium, leaching of zinc in a concentrated alkaline solution and followed by drying and annealing at 400 °C. The structure and morphology of the obtained Co3O4 electrodes were characterized by X-ray diffraction, EDX analysis and scanning electron microscopy. The results showed that the obtained Co3O4 electrodes were composed of the nanoporous/cracked structures with an average pore size of about 100 nm. The electrochemical capacitive behaviors of the nanoporous Co3O4 electrodes were investigated by cyclic...
Hydrothermal synthesis and characterization of titanium dioxide nanotubes as novel lithium adsorbents
, Article Materials Research Bulletin ; Vol. 61, issue , January , 2014 , p. 70-75 ; Hajipour, H ; Askari, M ; Nusheh, M ; Sharif University of Technology
Abstract
The ion exchange process is a promising method for lithium extraction from brine and seawater having low concentrations of this element. To achieve this goal, it is vital to use an effective adsorbent with maximum lithium adsorption potential together with a stable structure during extraction and insertion of the ions. In this study, titanium dioxide and then lithium titanate spinel with nanotube morphology was synthesized via a simple two-step hydrothermal process. The produced Li4Ti5O12 spinel ternary oxide nanotube with about 70 nm diameter was then treated with dilute acidic solution in order to prepare an adsorbent suitable for lithium adsorption from local brine. Morphological and...
Pure commercial titanium color anodizing and corrosion resistance
, Article Journal of Materials Engineering and Performance ; Volume 20, Issue 9 , 2011 , Pages 1690-1696 ; 10599495 (ISSN) ; Afshar, A ; Ghahramani, S ; Malekinejad, P ; Sharif University of Technology
Abstract
In order to improve titanium corrosion behavior, we can increase the thickness of oxide layer on titanium surface during anodizing process and by electrochemistry. In this research, self-color anodizing of Ti in sulfuric acid was done, and anodizing layers were created in different colors. The highest value of chromaticity was 37.8 for the anodized sample in 10 V, and the lowest value was 8.6 at 15 V. The oxide layer thickness was calculated by optical method (light refraction). The anodic film thickness increased by increasing the anodizing voltage. The highest thickness of anodic film was 190 nm in sulfuric acid solution for the anodized sample in 80 V. Corrosion resistance of anodized Ti...
Thermal characteristics of closed loop pulsating heat pipe with nanofluids
, Article Journal of Enhanced Heat Transfer ; Volume 18, Issue 3 , 2011 , Pages 221-237 ; 10655131 (ISSN) ; Arabnejad, S ; Shafii, M. B ; Saboohi, Y ; Sharif University of Technology
2011
Abstract
In this paper, the effect of different parameters on the thermal operation of a Closed Loop Pulsating Heat Pipe (CLPHP) has been investigated. These parameters include the working fluid, the inclination angle, the filling ratio, and the input heat flux. The effect of nanoparticle mass concentrations has been analyzed as well. It was observed that the CLPHP can decrease thermal resistance up to 11.5 times compared to the same empty copper tube with thermal resistance of 9.4 K/W. Optimum thermal operation for a system with the water-silver nanofluid was achieved at conditions of the 50% filling ratio with thermal resistance of 0.9 K/W, and for the water-titanium oxide system, the optimal...
Hydrothermal synthesis and characterization of titanium dioxide nanotubes as novel lithium adsorbents
, Article Materials Research Bulletin ; Volume 61 , 2015 , Pages 70-75 ; 00255408 (ISSN) ; Hajipour, H ; Askari, M ; Nusheh, M ; Sharif University of Technology
Elsevier Ltd
2015
Abstract
The ion exchange process is a promising method for lithium extraction from brine and seawater having low concentrations of this element. To achieve this goal, it is vital to use an effective adsorbent with maximum lithium adsorption potential together with a stable structure during extraction and insertion of the ions. In this study, titanium dioxide and then lithium titanate spinel with nanotube morphology was synthesized via a simple two-step hydrothermal process. The produced Li4Ti5O12 spinel ternary oxide nanotube with about 70 nm diameter was then treated with dilute acidic solution in order to prepare an adsorbent suitable for lithium adsorption from local brine. Morphological and...
Self-organized titanium oxide nanotubes prepared in phosphate electrolytes: Effect of voltage and fluorine concentration
, Article ECS Transactions, 25 April 2010 through 30 April 2010 ; Volume 28, Issue 7 , April , 2010 , Pages 67-74 ; 19385862 (ISSN) ; 9781607681830 (ISBN) ; Dolati, A ; Goodarzi, M ; Askari, M ; Ghahramaninezhad, A ; ECS All Divisions ; Sharif University of Technology
2010
Abstract
TiO2 a nanotube array was prepared using an anodization process. The process proceeded in a two-electrode cell containing of platinum sheet as the cathode electrode. Two phosphate-base electrolyte solutions containing different amounts of HF and NH4F were prepared. Different concentration of fluorine ions were examined in respected electrolytes. Current transient techniques were used to produce the TiO2 nanotubes at constant voltage of 18-25V. It was revealed that anodization at 18-22V, in so-called electrolytes would end up to nano-tubular structure. However the tubular structure prepared at 20V and from phosphate electrolyte containing of 0.5 wt% NH4F as well as 0.5 wt% HF, was recognized...
(WO3)x-(TiO2)1-x nano-structured porous catalysts grown by micro-arc oxidation method: Characterization and formation mechanism
, Article Materials Chemistry and Physics ; Volume 124, Issue 1 , 2010 , Pages 203-207 ; 02540584 (ISSN) ; Moshfegh, A. Z ; Golestani Fard, F ; Molaei, R ; Sharif University of Technology
2010
Abstract
Very recently, we fabricated (WO3)x-(TiO 2)1-x layers via micro-arc oxidation process under different applied voltages. Morphological and topographical studies, accomplished by SEM and AFM techniques, revealed that the pores size as well as the surface roughness increased with the voltage. Phase structure and chemical composition of the layers were also investigated by XRD and XPS and the results showed the grown layers consisted of titanium and tungsten oxides. It was found that WO3 dispersed in the TiO2 matrix and also doped into the TiO2 lattice. In addition, optical properties of the synthesized layers were studied employing a UV-vis spectrophotometer. Band gap energy of the layers was...
Synthesis and characterization of nanocrystalline barium strontium titanate
, Article Materials Science- Poland ; Volume 28, Issue 2 , 2010 , Pages 421-426 ; 01371339 (ISSN) ; Nemati, Z. A ; Faghihi Sani, M. A ; Sharif University of Technology
2010
Abstract
Barium strontium titanate (BST) was prepared via the simple sol-gel method by using tetrabutyl ti-tanate, ethanol, citric acid and ethylene glycol as starting materials. Thermogravimetry and differential thermal analysis were used to examine the behaviour of the xerogel. The particle size of BST was approximately 21 nm, as calculated by the X-ray diffraction and confirmed by transition electron microscopy for the calcination temperature of 750 °C. It was found that the particles of BST powders calcined at 750 °C were smaller and more homogeneous and uniform than those obtained at 800 °C
How photocatalytic activity of the MAO-grown TiO2 nano/micro-porous films is influenced by growth parameters?
, Article Applied Surface Science ; Volume 256, Issue 13 , 2010 , Pages 4253-4259 ; 01694332 (ISSN) ; Golestani Fard, F ; Moshfegh, A. Z ; Sharif University of Technology
2010
Abstract
Pure titania porous layers consisted of anatase and rutile phases, chemically and structurally suitable for catalytic applications, were grown via micro-arc oxidation (MAO). The effect of applied voltage, process time, and electrolyte concentration on surface structure, chemical composition, and especially photocatalytic activity of the layers was investigated. SEM and AFM studies revealed that pore size and surface roughness of the layers increased with the applied voltage, and the electrolyte concentration. Moreover, the photocatalytic performance of the layers synthesized at medium applied voltages was significantly higher than that of the layers produced at other voltages. About 90% of...
Photo-degradation of methelyne blue over V2O5- TiO2 nano-porous layers synthesized by micro arc oxidation
, Article Catalysis Letters ; Volume 134, Issue 1-2 , 2010 , Pages 162-168 ; 1011372X (ISSN) ; Golestani Fard, F ; Zaker Moshfegh, A ; Sharif University of Technology
Abstract
V2O5-TiO2 porous layers were synthesized via micro-arc oxidation for the first time. The effect of the applied voltage on morphology, composition, and photo-activity of the layers was investigated. The layers, which consisted of anatase, rutile, and vanadium pentoxide phases, revealed an enhanced photo-activity. About 93% of methylene blue solution was degraded on the synthesized layers after 120 min UV-irradiation with a reaction rate constant of k = 0.0228 min-1. The band gap energies of the vanadia-titania and pure titania layers were calculated as 2.56 and 3.39 eV, respectively
Deposition of (Ti, Ru)O2 and (Ti, Ru, Ir)O2 oxide coatings prepared by sol–gel method on titanium
, Article Journal of Sol-Gel Science and Technology ; Volume 79, Issue 1 , 2016 , Pages 44-50 ; 09280707 (ISSN) ; Ghorbani, M ; Sharif University of Technology
Springer New York LLC
Abstract
Titanium anodes activated by noble metal oxides possess a wide range of advantages and applications. Actually, coating of titanium anodes by highly conductive oxides of noble metals (Ru, Ir) dramatically increases the lifetime of these anodes. In this study, the binary coating consisting of Ti and Ru and the ternary coating consisting of Ti, Ru and Ir were prepared through sol–gel method. After coating of the titanium substrate, the corrosion behavior of coatings was studied by anodic polarization and cyclic voltammetry tests. The lifetime of anodes was determined using accelerated corrosion test. The morphology of coatings was examined by field emission scanning electron microscopy and...
Selecting Support Layer for Electrodeposited Efficient Cobalt Oxide/Hydroxide Nanoflakes to Split Water
, Article ACS Sustainable Chemistry and Engineering ; Volume 4, Issue 6 , 2016 , Pages 3151-3159 ; 21680485 (ISSN) ; Esfandiar, A ; Qorbani, M ; Moshfegh, A. Z ; Sharif University of Technology
American Chemical Society
2016
Abstract
Energy and environment crises motivated scientists to develop sustainable, renewable, and clean energy resources mainly based on solar hydrogen. For this purpose, one main challenge is the low cost flexible substrates for designing earth abundant efficient cocatalysts to reduce required water oxidation overpotential. Here, a systematic morphological and electrochemical study has been reported for cobalt oxide/hydroxide nanoflakes simply electrodeposited on four different commercially available substrates, titanium, copper sheet, steel mesh, and nickel foam. Remarkable dependence between the used substrate, morphology, and electrocatalytic properties of nanoflakes introduced flexible porous...
Experimental investigation of closed loop pulsating heat pipe with nanofluids
, Article Proceedings of the ASME Summer Heat Transfer Conference 2009, HT2009 ; Volume 1 , 2009 , Pages 675-683 ; 9780791843567 (ISBN) ; Arabnejad, S ; Behshad Shafii, M ; Saboohi, Y ; Rasoulian, R ; Sharif University of Technology
Abstract
In this paper, the effect of several different parameters on the thermal resistance of a Closed Loop Pulsating Heat Pipe (CLPHP) has been investigated. These parameters include the working fluid, the inclination angle, the filling ratio and the heat influx. Also, the impact of using nanofluids with different nano-particle concentrations has been analyzed. It was observed that a CLPHP can increase the heat transfer up to 11.5 times compared to an empty pipe. Optimum performance for a system with the water-silver nanofluid was achieved at conditions of 50% filling ratio and 0.9 K/W of thermal resistance, and for the water-titanium oxide system, these optimal conditions were found to be 40%...
Synthesis photocatalytic TiO2/ZnO nanocomposite and investigation through anatase, wurtzite and ZnTiO3 phases antibacterial behaviors
, Article Journal of Nano Research ; Volume 51 , 2018 , Pages 69-77 ; 16625250 (ISSN) ; Ghorbani, M ; Sharif University of Technology
Trans Tech Publications Ltd
2018
Abstract
Titanium dioxide is prepared by sol gel method from titanium tetraisopropoxide (TTIP) as precursor and likewise zinc oxide is prepared by sol gel method from zinc acetate dehydrate (ZAD) as precursor. The composite sols are prepared in three different molar ratios 90TiO2:10ZnO, 70TiO2:30ZnO and 50TiO2:50ZnO. Thin film deposition is carried out by dip coating technique. Crystal structure, surface morphology and photocatalytic activity of the prepared nanocomposite thin films are investigated. The antibacterial activity of the prepared nanocomposite thin film against E-coli ATCC 25922 bacteria is examined by placing the thin film in standard aqueous E-coli medium under UV light for 1, 2, 3 and...
Capping antibacterial Ag nanorods aligned on Ti interlayer by mesoporous TiO2 layer
, Article Surface and Coatings Technology ; Volume 203, Issue 20-21 , 2009 , Pages 3123-3128 ; 02578972 (ISSN) ; Ghaderi, E ; Sharif University of Technology
2009
Abstract
In this work, aligned and compact Ag nanorods capped by sol-gel mesoporous TiO2 layer were grown on Ti/Si(100) in order to be applied in antibacterial applications. The Ag nanorods with a high effective surface were grown by applying an electric field perpendicular to the surface of the Ag/Ti/Si thin film while it was being heat-treated at 700 °C in an Ar + H2 ambient. The grown silver nanorods had widths and lengths of 20-50 and 250-500 nm with an abundance in {100} facet, respectively. The TiO2 cap layer also had the specific surface area, the total pore volume and the pore diameter of 474 m2/g, 0.49 cm3/g and 8.0 nm, respectively. Antibacterial activities of the TiO2-capped Ag nanorods...
Mixed-phase TiO2 nanoparticles preparation using sol-gel method
, Article Journal of Alloys and Compounds ; Volume 478, Issue 1-2 , 2009 , Pages 586-589 ; 09258388 (ISSN) ; Askari, M ; Sasani Ghamsari, M ; Afshar, N ; Lahuti, S ; Sharif University of Technology
2009
Abstract
Biphase TiO2 nanoparticles have been prepared by sol-gel method. Water/titanium molar ratio (r) has been used to control the hydrolysis and condensation of titanium isopropoxide in solution producing titanium oxide with two different polymorphs. The influence of crystallite size and morphology of prepared TiO2 on the phase transformation of the resultant materials has been investigated. Synthesized powders were characterized by X-ray diffraction, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Different trends can be observed in the phase transformation and particle growth of the prepared titanium oxide nanomaterial. It was concluded that, the rate of particle...
Alkali metal cation incorporation in conductive TiO2 nanoflakes with improved photoelectrochemical h2 generation
, Article ChemElectroChem ; Volume 7, Issue 7 , March , 2020 , Pages 1699-1706 ; Mohajernia, S ; Hejazi, S ; Mehdipour, H ; Naseri, N ; Moradlou, O ; Liu, N ; Moshfegh, A. Z ; Schmuki, P ; Sharif University of Technology
Wiley-VCH Verlag
2020
Abstract
In this research, we investigate the effect of alkali metal cations including Li, Na and Cs in hydrothermal solution on the morphology, stability, and photoactivity of nanostructured TiO2 nanoflakes as a photoanode. The TiO2 nanoflakes are formed through hydrothermal treatment of Ti foil in 1.0 M LiOH, NaOH or CsOH at 100 °C for 3 h. By subsequent thermal reduction of the structure in an optimized Ar/H2 environment, conductive TiO2 nanoflakes were formed. The reduction treatment remarkably improves the photocurrent density of the TiO2 nanoflakes and has the highest impact on the sample treated in the NaOH alkali solution. For the nanoflakes produced in NaOH alkali solution, the bandgap is...
Anti-reflection and self-cleaning meso-porous TiO2 coatings as solar systems protective layer: Investigation of effect of porosity and roughness
, Article Optical Materials ; Volume 107 , 2020 ; Afshar, A ; Azadeh, M ; Sharif University of Technology
Elsevier B.V
2020
Abstract
Anti-reflection and self-cleaning coatings on the glass substrate are used to improve the performance of solar systems. TiO2 are one of the most used semiconductors for this application. In this research meso-porous TiO2 coatings (that synthesized by the sol-gel process) with the various extent of porosity (using different concentrations of Pluronic F127, as pore-forming agent) have been investigated. The coating's thickness and porosity and anti-reflective properties were studied by FE-SEM and UV/VIS spectrometer (transmission spectra test), respectively. It was found that the use of F127 leads to the formation of pores smaller than 30 nm and increases the surface roughness from 1.5 (for...
Lasting antibacterial activities of Ag-TiO2/Ag/a-TiO2 nanocomposite thin film photocatalysts under solar light irradiation
, Article Journal of Colloid and Interface Science ; Volume 336, Issue 1 , 2009 , Pages 117-124 ; 00219797 (ISSN) ; Sharif University of Technology
2009
Abstract
Photodegradation of Escherichia coli bacteria in presence of Ag-TiO2/Ag/a-TiO2 nanocomposite film with an effective storage of silver nanoparticles was investigated in the visible and the solar light irradiations. The nanocomposite film was synthesized by sol-gel deposition of 30 nm Ag-TiO2 layer on ∼200 nm anatase(a-)TiO2 film previously doped by silver nanoparticles. Both Ag/a-TiO2 and Ag-TiO2/Ag/a-TiO2 films were transparent with a SPR absorption band at 412 nm. Depth profile X-ray photoelectron spectroscopy showed metallic silver nanoparticles with diameter of 30 nm and fcc crystalline structure were self-accumulated on the film surface at depth of 5 nm of the TiO2 layer and also at the...