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hydrothermal-synthesis
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Controlled crystallization of LTA zeolitic nanoparticles from a clear solution using organic template
, Article Iranian Journal of Chemistry and Chemical Engineering ; Volume 30, Issue 2 , 2011 , Pages 9-14 ; 10219986 (ISSN) ; Kazemian, H ; Bastani, D ; Sharif University of Technology
2011
Abstract
LTA Zeolite nanoparticles was successfully synthesized from clear solution under controlled conditions using hydrothermal method using tetramethyl ammonium hydroxide as a structural directing agent. The as-synthesized LTA zeolite particles were characterized by powder X-ray Diffraction (XRD) analysis, Scanning Electron Microscopy (SEM), Fourier Transform InfraRed (FT-IR) spectroscopy, Energy Dispersive X-ray (EDX) analysis and surface area measuring technique of Brunauer, Emmett and Teller (BET). XRD patterns and FT-IR spectra were ascertained the formation of pure crystalline phase of 4A (i.e. LTA) zeolite. SEM micrograph was shown particles size in the range of 60 -170 nm with uniform...
Defect study of TiO2 nanorods grown by a hydrothermal method through photoluminescence spectroscopy
, Article Journal of Luminescence ; Volume 157 , January , 2015 , Pages 235-242 ; 00222313 (ISSN) ; Shogh, S ; Iraji Zad, A ; Sharif University of Technology
Elsevier
2015
Abstract
This paper describes the photoluminescence study of titanium dioxide (TiO2) nanorods grown by a hydrothermal synthesis method on the surface of fluorine doped tin oxide (FTO) coated glass. The effects of growth conditions including: reaction time, precursor concentration and adding NaCl to hydrothermal solution on the structural and optical properties of productions are examined by using SEM, XRD, TEM and room temperature photoluminescence measurements. Also, the performance of the TiO2 nanorods as a photoanode of dye sensitized solar cells is investigated. The different excitation energies and intensities are chosen to verify the discrete electronic state of radiative recombination centers...
Adsorption of lead ions in aqueous solution using Yttrium oxide nanoparticles
, Article Journal of Nano Research ; Volume 16 , 2011 , Pages 83-87 ; 16625250 (ISSN) ; Ahmadi, S. J ; Hosseinpour, M ; Sharif University of Technology
2011
Abstract
By a single-step supercritical hydrothermal synthesis method, yttrium oxide nanoparticles were successfully prepared without additional treatment. Yttrium oxide nanoparticles were employed as an adsorbent to study the adsorption of some heavy metal ions. This study revealed that nano structure yttrium oxide was an effective adsorbent for removal of lead ions from aqueous solutions
Investigation of Sintering Behavior of BaTiO3 Nanoparticles Synthesized Via Hydrothermal Method
, M.Sc. Thesis Sharif University of Technology ; Nemati, Ali (Supervisor) ; Simchi, Abdolreza (Supervisor)
Abstract
In the present work, Barium Titanate nanoparticles were synthesized by a facile hydrothermal method at 180oC for 4 hours and their sintering behavior was studied. The characterization tests illustrated that the obtained powder was BaTiO3 single phase with excess Ti content from stoichiometric composition. The average particle size of about 50 nm and a narrow particle size distribution was noticed. SEM investigations showed that the samples sintered at temperatures less than 1250oC had plate-like grains. This behavior resulted from twin plates existed in the grains and facetted grain boundaries. At the temperatures more than 1250oC, the grains became polygonal due to the formation of trace...
Investigating the Effect of Conditions and Synthetic Methods on the Characteristics Zinc-Based Metal-Organic Framework
, M.Sc. Thesis Sharif University of Technology ; Bagherzadeh, Mojtaba (Supervisor)
Abstract
In this research, the effect of changing the synthesis parameter of the anion with the central metal, the effect of different hydrothermal and reflux synthesis methods, as well as the effect of reaction time on the properties of the Metal-Organic framework (such as morphology, crystallinity, pore size and volume) of ZnPMA (PMA: 1, 2, 4, 5-benzenetetra carboxylic acid) was investigated. for this purpose, firstly the desired Metal-Organic Frameworks were prepared by interacting the 1, 2, 4, 5-benzenetetracarboxylic acid linker with the metal ion Zn2+ obtained from the metal salts Zn(OAC)2, ZnCl2, Zn(NO3)2 and ZnSO4 under reflux and hydrothermal conditions. also to investigate the effect of...
, M.Sc. Thesis Sharif University of Technology ; Alemzadeh, Iran (Supervisor) ; Vosoughi, Manouchehr (Co-Advisor)
Abstract
Nowadays with the extension of industry and factories as well as different kinds of plants, a wide range of pollution and circumference hazardous has been entered to the people`s life. Industrial wastewater has been always a threat for health of our environment and efforts for reducing its dangerous effects are still under studies. Dairy wastewater is one of the main branches of food industrial pollutions and it has been studied in this specific project. The goal was to reduce the Chemical Oxygen Demands (COD) of dairy wastewater with oxidation of Titanium Dioxide Nanophotocatalyst oxidation under UV irradiation. Among the various methods for synthesizing of this Nanophotocatalyst, the...
The Effect of Morphology on the Photocatalytic Properties of Nanostructured Pure Tio2 Simultaneously Doped with Carbon and Nitrogen
, M.Sc. Thesis Sharif University of Technology ; Maddah Hosseini, Hamid Reza (Supervisor) ; Mohammadi, Mohammad Reza (Supervisor)
Abstract
Improvement of semiconductors photocatalytic activity by different means has always been one of the challenges for researchers. Semiconductors doping for band-gap engineering and changing morphology to increase specific surface area and photocatalytic reaction sites are amongst these efforts. In this research simultaneous effect of these two parameters for three morphologies containing nanoparticle, nanowire and micro dandelion, simultaneously doped with carbon and nitrogen has been investigated. Final purpose of this thesis is to decrease the band-gap energy close to soft UV photon energies to make surface photodynamic therapy possible. Nanoparticle morphology with size distribution between...
Rapid high-temperature synthesis of SAPO-34 nanoparticles
, Article Particuology ; Volume 9, Issue 5 , October , 2011 , Pages 452-457 ; 16742001 (ISSN) ; Kazemian, H ; Soltanieh, M ; Rohani, S ; Hosseinpour, M ; Sharif University of Technology
2011
Abstract
Decreasing particle size results in larger increase of external surface area and shorter diffusion path, both reducing mass and heat transfer resistances in catalysis and sorption. A rapid high-temperature hydrothermal synthesis method was developed to synthesize uniform nanoparticles of SAPO-34 zeolite with high crystallinity. To investigate the effects of temperature and synthesis time on purity and crystallinity of the final products, the crystallization temperature was increased from 468 to 673 K while the synthesis time was decreased from 24 h to 45 min. The products were characterized by XRD and SEM techniques. It was found that high temperature and short synthesis time reduce the...
TiO2 surface nanostructuring for improved dye loading and light scattering in double-layered screen-printed dye-sensitized solar cells
,
Article
Journal of Applied Electrochemistry
;
Volume 45, Issue 8
,
2015
,
Pages 831-838
;
0021891X (ISSN)
; Moakhar, R. S
; Kushwaha, A
; Goh, G. K. L
; Sadrnezhaad, S. K
; Riahi Noori, N
;
Sharif University of Technology
Kluwer Academic Publishers
2015
Abstract
Abstract: Surface-nanostructured TiO2 nanorods were synthesized hydrothermally at 180 °C. Such nanorods have ‘crack-like’ surfaces that resemble burnt charcoal. Compared to nanorods with relatively smoother surfaces, the charcoal-like nanorods have higher-specific surface areas. By using the nanorods as a light-scattering layer in double-layered dye-sensitized solar cells, the cells based on the charcoal-like nanorods have 20 % higher dye loading and also higher diffuse reflectance compared with cells utilizing ‘smooth’ nanorods. The efficiency of a screen-printed double-layer dye-sensitized solar cell based on the charcoal-like nanorods is higher at 7.29 %. Electrochemical...
Magnetic stirring assisted hydrothermal synthesis of Na3MnCO3PO4 cathode material for sodium-ion battery
, Article Ceramics International ; Volume 47, Issue 19 , 2021 , Pages 26929-26934 ; 02728842 (ISSN) ; Sadrnezhaad, S.K ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
Na3MnCO3PO4 (NMCP) is considered one of the promising cathode materials for sodium-ion batteries due to its high theoretical capacity. The hydrothermal method is an efficient, environmental-friendly, and simple route with low instrument cost to prepare active cathode materials such as NMCP. In this research, magnetic stirring was applied to promote the hydrothermal synthesis, and NMCP was produced by controlling different stirring times. This method results in the formation of pure NMCP upon only 45 min processing time. According to the ICP results, the Na to Mn ratio in the NMCP approached the stoichiometric value of 3 by prolonging the stirring time. By analyzing the charge-discharge...
Electrochemical Degradation of Organic Pollutants in the Presence of Spinel Cobalt Ferrite Nanoparticles: Investigation of the Effective Parameters and Evaluation of Degradation Kinetics
, M.Sc. Thesis Sharif University of Technology ; Rahman Setayesh, Shahrbanoo (Supervisor)
Abstract
In this study, CoFe2O4/CuO nanocomposite was synthesized by hydrothermal method and utilized for removal of metronidazole in electro-Fenton process. Nanocomposite was characterized by FT-IR, XRD, FE-SEM, VSM and BET methods. The Results of XRD patterns confirmed the monoclinic structure formation for copper(Ⅱ) oxide and the spinel structure for CoFe2O4. The FE-SEM images displayed the formation of CuO nanosheets for copper(Ⅱ) oxide and the decoration of cobalt ferrite nanoparticles on the surface of CuO nanosheets. Measurement of the surface area of nanocatalysts using BET isotherm represented the high surface area for CuO nanosheets and the increase of surface area of nanocomposite in...
Synthesis of Titania Coated Upconversion Nanoparticles with the Capability of Being Utilized in Photodynamic Therapy Under the Near-Infrared Radiation
, Ph.D. Dissertation Sharif University of Technology ; Madaaah Hosseini, Hamid Reza (Supervisor) ; Soleimani, Masoud (Supervisor) ; Mohajerani, Ezeddin (Co-Supervisor)
Abstract
Development of novel photosensitizers and photocatalysts with near-infrared (NIR) light activity and efficient sunlight harvesting is of great importance in photodynamic therapy and environmental remediation. In this work, very small (20 nm) upconverter SrF2:Yb,Tm@CaF2:Yb@Fluorine-doped TiO2 heteronanoparticles (denoted as UCNPs@TiO2) with strong UV-blue emission and wide-spectrum photocatalytic activity were synthesized via a facile three-step hydrothermal method, for the first time. The SrF2: Yb,Tm upconverter nanoparticles were produced as the light-emitting core, epitaxially-grown CaF2 : Yb as the middle shell to enhance the Upconversion luminescence efficiency and TiO2 as the...
Application of the statistical Taguchi method to optimize TiO2 nanoparticles synthesis by the hydrothermal assisted sol-gel technique
, Article Ceramics International ; Vol. 40, Issue 3 , 2014 , pp. 4193-4201 ; ISSN: 02728842 ; Faghihi Sani, M. A ; Madaah Hosseini, H. R ; Sharif University of Technology
Abstract
TiO2 nanoparticles were synthesized by hydrothermal assisted sol-gel technique. The preparation parameters including pH value, the amount of water, titanium tetra isopropoxide content, temperature and time of hydrothermal process were investigated by Taguchi statistical experiments to determine the influence of synthesizing variables on the optimal conditions and to realize the highest degree of crystallinity or smallest crystallite size. X-ray diffraction (XRD) analysis and direct band gap energy (Eg) values, measured via diffuse reflectance spectra (DRS), proved that all the samples consist of anatase as a unique phase. Transmission electron microscopy (TEM) and specific surface area...
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...
High temperature synthesis of SAPO-34: applying an L9 taguchi orthogonal design to investigate the effects of experimental parameters
, Article Powder Technology ; Volume 217 , February , 2012 , Pages 223-230 ; 00325910 (ISSN) ; Kazemian, H ; Soltanieh, M ; Hosseinpour, M ; Rohani, S ; Sharif University of Technology
Abstract
SAPO-34 zeolite-like particles were successfully synthesized at high temperature environment. An L9 orthogonal array of the Taguchi method was implemented to investigate the effects of experimental conditions to prepare SAPO-34 with respect to crystallinity of the final product phase. The results showed that the favorable phase crystallinity was improved by increasing the hydrothermal synthesis temperature and organic template content, whereas increasing the water content in synthesis mixture decreased the crystallinity. No significant changes in crystallinity of the final products were observed by increasing the synthesis duration. In addition, zeolite SAPO-5, which was formed as the...
Hydrothermal synthesis and characterization of TiO 2 nanostructures using LiOH as a solvent
, Article Advanced Powder Technology ; Volume 22, Issue 3 , 2011 , Pages 336-339 ; 09218831 (ISSN) ; Kajbafvala, A ; Zanganeh, N ; Molaei, R ; Bayati, M. R ; Zargar, H. R ; Sadrnezhaad, S. K ; Sharif University of Technology
2011
Abstract
In the present study, we performed hydrothermal method as a simple and efficient route for the synthesis of rutile TiO 2 nanostructures in various concentrations of lithium hydroxide solutions. TiO 2 nanopowders with average sizes of 15 and 23 nm were prepared using 4 M and 7 M LiOH solutions. X-ray diffraction analysis (XRD), transmission electron microscope (FEG-STEM), scanning electron microscopy (SEM), and Brunauer-Emmet-Teller (BET) analyses were used in order to characterize the obtained products and comparison of the morphology of the powders obtained in different concentrations of LiOH solvent. It was shown that alkali solution concentration has affected the crystallinity,...
Hydrothermal synthesis of CuO nanoparticles: Study on effects of operational conditions on yield, purity, and size of the nanoparticles
, Article Industrial and Engineering Chemistry Research ; Volume 50, Issue 6 , February , 2011 , Pages 3540-3554 ; 08885885 (ISSN) ; Hosseinpour, M ; Ahmadi, S. J ; Mousavand, T ; Sadjadi, S ; Soltanian, W ; Sharif University of Technology
Abstract
Hydrothermal synthesis of CuO nanoparticles under near-critical and supercritical conditions was investigated from two different standpoints in the current study. The first standpoint was optimization of "yield", "purity", and "size of the nanoparticles" that were optimized at T = 500 °C, time = 2 h, [Cu(NO3)2] = 0.1 mol dm-3, and pH 3. This was achieved by undertaking an orthogonal experiment design methodology and performing different instrumental analyses, such as X-ray diffractometry, inductively coupled plasma spectrometry, and transmission electron microscopy, along with treatment of the data by analysis of variance (ANOVA). The second goal of the study was elucidation of the...
Hydrothermal synthesis of TiO2 nanocrystals in different basic pHs and their applications in dye sensitized solar cells
, Article Physica E: Low-Dimensional Systems and Nanostructures ; Volume 70 , June , 2015 , Pages 113-120 ; 13869477 (ISSN) ; Marandi, M ; Taghavinia, N ; Sharif University of Technology
Elsevier
2015
Abstract
In this research TiO2 nanocrystals with sizes about 11-70 nm were grown by hydrothermal method. The process was performed in basic autoclaving pH in the range of 8.0-12.0. The synthesized anatase phase TiO2 nanocrystals were then applied in the phtoanode of the dye sensitized solar cells. It was shown that the final average size of the nanocrystals was larger when the growth was carried out in higher autoclaving pHs. The photoanodes made of TiO2 nanocrystals prepared in the pHs of 8.0 and 9.0 represented low amounts of dye adsorption and light scattering. The performance of the corresponding dye sensitized solar cells was also not acceptable. Nevertheless, the energy conversion efficiency...
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...
Optimization of parameters for synthesis of mfi nanoparticles by taguchi robust design
, Article Chemical Engineering and Technology ; Volume 33, Issue 6 , 2010 , Pages 902-910 ; 09307516 (ISSN) ; Soltanieh, M ; Kazemian, H ; Sharif University of Technology
2010
Abstract
MFI-type zeolite was successfully synthesized by hydrothermal crystallization of clear synthesis mixtures. A statistical experimental design method (the Taguchi method with an L8 orthogonal array) was implemented to optimize the experimental conditions for the preparation of MFI nanocrystals with respect to particle size and distribution as the desirable properties. In the Taguchi experimental design, crystallization temperature, water content, template/silica molar ratio, aluminum content, as well as the presence of alkaline cations were chosen as significant parameters affecting the properties. It was shown that water and aluminum content of the synthesis solution were the most important...