scholarly journals The Synthesis of Anatase Nanoparticles and the Preparation of Photocatalytically Active Coatings Based on Wet Chemical Methods for Self-Cleaning Applications

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Dejan Verhovšek ◽  
Nika Veronovski ◽  
Urška Lavrenčič Štangar ◽  
Marko Kete ◽  
Kristina Žagar ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Sol Gel ◽  
Synthesis Method ◽  
Photocatalytic Effect ◽  
Transmission Electron ◽  
Anatase Nanoparticles ◽  
Wet Chemical ◽  
Self Cleaning ◽  
Nanoparticle Coatings ◽  
Sol Gel Synthesis

We report on an improved sol-gel method for the production of highly photocatalytic titanium dioxide (TiO2) anatase nanoparticles which can provide appropriate control over the final characteristics of the nanoparticles, such as particle size, crystallinity, crystal structure, morphology, and also the degree of agglomeration. The synthesized anatase nanoparticles were characterized using various techniques, such as X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), and were tested in coatings for self-cleaning glass and ceramic surfaces. The coatings were prepared using a soft chemistry route and are completely transparent to visible light and exhibit a high photocatalytic effect, which was determined by contact-angle measurements. Finally, it is worth mentioning that both the sol-gel synthesis method and the coating-preparation method are based on a wet chemical process, thus presenting no risk of handling the TiO2anatase nanoparticles in their potentially hazardous powder form at any stage of our development. Low-price, easy-to-handle, and nontoxic materials were used. Therefore, our work represents an important contribution to the development of TiO2anatase nanoparticle coatings that provide a high photocatalytic effect and can thus be used for numerous applications.

scholarly journals Magnetic PbFe12O19-TiO2 nanocomposites and their photocatalytic performance in the removal of toxic pollutants

2018 ◽  
Vol 41 (3-4) ◽  
pp. 53-62 ◽  
Author(s):  
Behnaz Lahijani ◽  
Kambiz Hedayati ◽  
Mojtaba Goodarzi
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Performance ◽  
Sol Gel ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Gel Method ◽  
Sol Gel Method ◽  
Photocatalytic Effect ◽  
Transmission Electron ◽  
Ultraviolet Light Irradiation

Abstract In this work, the PbFe12O19 nanoparticles were prepared by the simple and optimized precipitation method with different organic surfactants and capping agents. In the next step, the TiO2 nanoparticles were synthesized using the sol-gel method. At the final step, the PbFe12O19-TiO2 nanocomposites were prepared via the sol-gel method. The effect of the precipitating agent on the morphology and particle size of the products was investigated. The prepared products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Fourier transform infrared spectroscopy. The results obtained by the vibrating sample magnetometer show the magnetic properties of the ferrite nanostructures. The photocatalytic effect of the PbFe12O19-TiO2 nanocomposite on the elimination of the azo dyes (acid black, acid violet and acid blue) under ultraviolet light irradiation was evaluated. The results indicate that the prepared nanocomposites have acceptable magnetic and photocatalytic performance.

scholarly journals Sol-Gel Derived Eu3+-Doped Gd2Ti2O7Pyrochlore Nanopowders

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Sanja Ćulubrk ◽  
Željka Antić ◽  
Vesna Lojpur ◽  
Milena Marinović-Cincović ◽  
Miroslav D. Dramićanin
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Structural Changes ◽  
Sol Gel ◽  
Pyrochlore Phase ◽  
Structural Defects ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Sol Gel Synthesis

Herein we presented hydrolytic sol-gel synthesis and photoluminescent properties of Eu3+-doped Gd2Ti2O7pyrochlore nanopowders. According to Gd2Ti2O7precursor gel thermal analysis a temperature of 840°C is identified for the formation of the crystalline pyrochlore phase. Obtained samples were systematically characterized by powder X-ray diffraction, scanning and transmission electron microscopy, and photoluminescence spectroscopy. The powders consist of well-crystalline cubic nanocrystallites of approximately 20 nm in size as evidenced from X-ray diffraction. The scanning and transmission electron microscopy shows that investigated Eu3+-doped Gd2Ti2O7nanopowders consist of compact, dense aggregates composed entirely of nanoparticles with variable both shape and dimension. The influence of Eu3+ions concentration on the optical properties, namely, photoluminescence emission and decay time, is measured and discussed. Emission intensity as a function of Eu3+ions concentration shows that Gd2Ti2O7host can accept Eu3+ions in concentrations up to 10 at.%. On the other hand, lifetime values are similar up to 3 at.% (~2.7 ms) and experience decrease at higher concentrations (2.4 ms for 10 at.% Eu3+). Moreover, photoluminescent spectra and lifetime values clearly revealed presence of structural defects in sol-gel derived materials proposing photoluminescent spectroscopy as a sensitive tool for monitoring structural changes in both steady state and lifetime domains.

scholarly journals Novel Sol-Gel Synthesis of Spherical Lead Titanate Submicrometer Powders

Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 484
Author(s):  
Radhouane Bel-Hadj-Tahar ◽  
Mohamed Abboud ◽  
Mohd. Shkir ◽  
Abdullah Alhanash ◽  
Ali Eisa M. Anqi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Lead Titanate ◽  
Sol Gel ◽  
Particle Morphology ◽  
Submicron Particles ◽  
X Ray Diffraction ◽  
Synthetic Process ◽  
Transmission Electron ◽  
Autogenous Pressure ◽  
Sol Gel Synthesis

In this study, a novel and simple synthetic sol-gel procedure was established to directly prepare spherical lead titanate powders without prior synthesis/usage of spherical templates such as TiO2 particles. Isotropic submicron particles with a mean diameter of 1–4 μm were prepared in this way. This synthetic process takes advantage of acetone as a stabilizing ligand and autogenous pressure generated in the autoclave during the reaction. The influence of various experimental factors (nature of the ligand, thermal treatment mode, and post-calcining temperature) as well as the formation mechanism were studied. Scanning electron microscopy and transmission electron microscopy were used to explore the particle morphology. The crystalline phases were explored and identified by X-ray diffraction analysis.

Pure and Ca-doped LaCoO3 Nanopowders: Sol-Gel Synthesis, Characterization and Magnetic Properties

2004 ◽  
Vol 848 ◽  
Author(s):  
Lidia Armelao ◽  
Davide Barreca ◽  
Gregorio Bottaro ◽  
Andrea Caneschi ◽  
Claudio Sangregorio ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Magnetic Properties ◽  
Chemical Composition ◽  
Auger Electron ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Sol Gel Synthesis

ABSTRACTThis work is focused on the sol-gel synthesis of pure and Ca-doped LaCoO3 nanopowders. The samples were prepared starting from methanolic solutions of cobalt (II) acetate (Co(CH3COO)2·4H2O), lanthanum (III) nitrate (La(NO3)3·6H2O) and calcium (II) acetate (Ca(CH3COO)2·H2O). After solvent evaporation, the obtained powders were dried under vacuum and subsequently treated in air up to 1273 K. The system evolution under thermal annealing was studied by X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM), while the chemical composition was analyzed by X-ray Photoelectron (XPS) and X-ray Excited Auger electron (XE-AES) spectroscopies. The temperature and field dependence of the magnetic properties of the Ca-doped samples were investigated, and compared to those of the corresponding pure LaCoO3 powders.

Facile Sol-Gel Synthesis of Mesoporous TiO2 in Ionic Liquids

2013 ◽  
Vol 389 ◽  
pp. 53-56
Author(s):  
Shu Guo ◽  
Sheng Xu Lu ◽  
Hui Ding ◽  
Zai Feng Shi
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Sol Gel ◽  
Rutile Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Carboxylate Groups ◽  
Transmission Electron ◽  
Xrd Patterns ◽  
Sol Gel Synthesis

The mesoporous TiO2 particles was conveniently prepared in a room temperature ionic liquid (RTILs) of 1, 3-di-(3-propionyloxy) imdazolium tetrafluoroborate [DiprCOOBF4 system. The obtained materials were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), and N2 adsorptiondesorption analysis. XRD patterns revealed that only rutile phase is formed in the RTILs. The TEM micrographs as well as N2 adsorptiondesorption measurements show that the prepared products exhibited wormlike pore structures. The FTIR (Fourier Transform Infrared Spectra) demonstrate the carboxylate groups attach via bidentate or bridging coordination to the TiO2 surface.

New Synthesis Method to Obtain Pd Nano-Crystals

2011 ◽  
Vol 14 ◽  
pp. 93-103 ◽  
Author(s):  
Magali Ugalde ◽  
E. Chavira ◽  
Martha T. Ochoa-Lara ◽  
Carlos Quintanar
Keyword(s):  
Electron Microscopy ◽  
Sol Gel ◽  
Synthesis Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
New Synthesis ◽  
Cubic Structure ◽  
Xerogel Sample ◽  
Xrd Studies

We report a new synthesis method to obtain palladium nano-crystals by sol-gel polymerized with acrylamide. From thermogravimetric analysis (TGA) studies, we found PdO and Pd compounds in the xerogel sample, at 550 °C, and over 900 °C we detected only metallic Pd. These results were corroborated by powder X-Ray Diffraction (XRD), High Resolution Scanning Electron Microscopy (HRSEM), and Transmission Electron Microscopy (TEM). XRD studies exhibit the lines from the tetragonal structure (PDF 41-1107) of PdO compound and from the cubic structure (PDF 46-1043) of Pd metallic. HRSEM micrographs show morphologies from the sample very sensitive to heat treatment. Finally, TEM images show crystals of ~8 nm in diameter.

Bi-Template Assisted Sol-Gel Synthesis of Photocatalytically-Active Mesoporous Anatase TiO2 Nanoparticles

2021 ◽  
Author(s):  
Abubakar Hamisu ◽  
Umar Ibrahim Gaya ◽  
Abdul Halim Abdullah
Keyword(s):  
Electron Microscopy ◽  
Uv Light ◽  
Sol Gel ◽  
Band Gap Energy ◽  
Hexadecyltrimethylammonium Bromide ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Sol Gel Synthesis ◽  
Adsorption Desorption

Sol-gel mesoporous titanium dioxide powders have been synthesized from chitosan and/or hexadecyltrimethylammonium bromide (HDTMA) and characterized using x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet-visible (UV-vis) spectroscopy, thermogravimetric analysis (TGA), differential thermal analysis (DTA) and N2 adsorption-desorption measurements. The photocatalytic performance of the synthesized meso-TiO2 powders was optimized based on the central composite design (CCD) of methyl orange (MO) degradation under UV light irradiation. The maximum MO degradation was 62.3% over a period of 60 min. Oxides produced using the binary chitosan and HDTMA template (C,H-TiO2) exhibited the relatively higher surface area (99.5 m2/g), smaller crystal size (12.78 nm), narrower band-gap energy (2.92 eV) and higher photocatalytic rate constant (0.0112 min–1) than as those from chitosan (C/TiO2) or HDTMA (H/TiO2) as the template.

Sub-Micrometer SiO2@ZnMoO4:Tb3+ Core-Shell Phosphors: Sol-Gel Synthesis and Characterization

2013 ◽  
Vol 800 ◽  
pp. 436-439
Author(s):  
Hu Yang ◽  
Xiao Bo Zhang ◽  
Juan Li ◽  
Yu Jun Lu
Keyword(s):  
Electron Microscopy ◽  
Sol Gel ◽  
Emission Spectra ◽  
Green Emission ◽  
Core Shell ◽  
Uniform Size ◽  
Tem Analysis ◽  
Transmission Electron ◽  
Shell Particles ◽  
Sol Gel Synthesis

ZnMoO4:Tb3+ phosphor layers were grown on monodisperse SiO2 particles through a simple sol-gel method, resulting in the formation of core-shell structured SiO2@ZnMoO4:Tb3+ sub-microspheres. The resulting SiO2@ZnMoO4:Tb3+ core-shell particles were characterized by powder X-ray diffraction(XRD), field emission scanning electron microscopy(FESEM), transmission electron microscopy(TEM) and photoluminescence(PL). SEM and TEM analysis indicates that the obtained sub-microspheres have a uniform size distribution and obvious core-shell structure. SiO2@ZnMoO4:Tb3+ sub-microspheres show strong green emission under ultraviolet(275nm) illumination and the emission spectra are dominated by a 5D4→7F5 transition of Tb3+(543nm,green) from the ZnMoO4:Tb3+ shells. The optimum concentration for Tb3+ was determined to be 5 mol% of Zn2+ in ZnMoO4 host shells.

Blue Emitting BaAl2O4:Ce3+ Nanophosphors with High Color Purity and Brightness for White LEDs

2019 ◽  
Vol 25 (6) ◽  
pp. 1466-1470 ◽  
Author(s):  
Rituparna Chatterjee ◽  
Subhajit Saha ◽  
Karamjyoti Panigrahi ◽  
Uttam Kumar Ghorai ◽  
Gopes Chandra Das ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Field Emission ◽  
Sol Gel ◽  
Blue Emission ◽  
Diffraction Field ◽  
White Leds ◽  
Display Devices ◽  
Transmission Electron ◽  
Structure Morphology ◽  
The Impact

AbstractIn this work, strongly blue emitting Ce3+-activated BaAl2O4 nanophosphors were successfully synthesized by a sol–gel technique. The crystal structure, morphology, and microstructure of the nanophosphors have been studied by X-ray powder diffraction, field emission scanning electron microscopy, and high-resolution transmission electron microscopy. The photoluminescence spectra show the impact of concentration variation of Ce3+ on the photoluminescence emission of the phosphor. These nanophosphors display intense blue emission peaking at 422 nm generated by the Ce3+ 5d → 4f transition under 350 nm excitation. Our results reveal that this nanophosphor has the capability to take part in the emergent domain of solid-state lighting and field-emission display devices.

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