scholarly journals Preparation and Characterization of a Calcium Carbonate Aerogel

2009 ◽  
Vol 2009 ◽  
pp. 1-3 ◽  
Author(s):  
Johann Plank ◽  
Heinz Hoffmann ◽  
Joachim Schölkopf ◽  
Wolfgang Seidl ◽  
Ingo Zeitler ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Calcium Carbonate ◽  
Sol Gel ◽  
Nitrogen Adsorption ◽  
Average Diameter ◽  
Supercritical Drying ◽  
Adsorption Method ◽  
X Ray ◽  
Sol Gel Process

We report on a facile method for the preparation of a calcium carbonate aerogel consisting of aggregated secondary vaterite particles with an approximate average diameter of 50 nm. It was synthesized via a sol-gel process by reacting calcium oxide with carbon dioxide in methanol and subsequent supercritical drying of the alcogel with carbon dioxide. The resulting monolith was opaque, brittle and had overall dimensions of  cm. It was characterized by X-ray powder diffraction, nitrogen adsorption method (BET), and scanning electron microscopy.

scholarly journals Sol-Gel Template Synthesis and Characterization of Lu2O3:Eu3+ Nanowire Arrays

Micromachines ◽  
2018 ◽  
Vol 9 (11) ◽  
pp. 601
Author(s):  
Yahua Hu ◽  
Mu Gu ◽  
Xiaolin Liu ◽  
Juannan Zhang ◽  
Shiming Huang ◽  
...  
Keyword(s):  
Sol Gel ◽  
Nanowire Arrays ◽  
X Ray Diffraction ◽  
Aao Template ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Sol Gel Process ◽  
Optical Luminescence ◽  
Uniform Diameter

Uniform Lu2O3:Eu3+ nanowire arrays were successfully prepared by the sol-gel process using anodic aluminum oxide (AAO) templates. The as-synthesized nanowires are homogeneous, highly ordered, and dense and have a uniform diameter of ~300 nm defined by the AAO templates. The X-ray diffraction and selected area electron diffraction results show that the Lu2O3:Eu3+ nanowires have a polycrystalline cubic structure, and the crystallite size of the Lu2O3:Eu3+ nanowires is confined by the AAO template. The nanowires within the AAO template showed good photoluminescence and X-ray-excited optical luminescence performances for Lu2O3:Eu3+. The emission peaks were attributed to the 5D0 → 7FJ transitions of Eu3+ (J = 0, 1, 2, 3).

Sol-gel derived Ba(Mg1/3Ta2/3)O3 thin films: Preparation and structure

1997 ◽  
Vol 12 (3) ◽  
pp. 596-599 ◽  
Author(s):  
Ji Zhou ◽  
Qing-Xin Su ◽  
K. M. Moulding ◽  
D. J. Barber
Keyword(s):  
Thin Films ◽  
Annealing Temperature ◽  
Volume Fraction ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Small Grains

Ba(Mg1/3Ta2/3)O3 thin films were prepared by a sol-gel process involving the reaction of barium isopropoxide, tantalum ethoxide, and magnesium acetate in 2-methoxyethanol and subsequently hydrolysis, spin-coating, and heat treatment. Transmission electron microscopy, x-ray diffraction, and Raman spectroscopy were used for the characterization of the thin films. It was shown that the thin films tend to crystallize with small grains sized below 100 nm. Crystalline phase with cubic (disordered) perovskite structure was formed in the samples annealed at a very low temperature (below 500 °C), and well-crystallized thin films were obtained at 700 °C. Although disordered perovskite is dominant in the thin films annealed below 1000 °C, a low volume fraction of 1 : 2 ordering domains was found in the samples and grows with an increase of annealing temperature.

Synthesis and Characterization of Cellular SiO2 Materials by Foaming Sol Gels

1990 ◽  
Vol 207 ◽  
Author(s):  
Josephine Covino ◽  
Allen P. Gehris
Keyword(s):  
Sol Gel ◽  
Optical Characterization ◽  
Viscosity Change ◽  
Density Measurements ◽  
X Ray ◽  
X Ray Crystallography ◽  
Foaming Process ◽  
Sol Gel Process ◽  
Porous Oxides

AbstractA variety of cellular SiO2 materials have been synthesized using a foaming sol-gel process and their properties have been characterized. The process uses the rapid viscosity change during gelation to stabilize the structure of a foamed silica sol. It was found that the properties of these cellular materials are determined by method used. For example, the porosity and strength of these porous oxides depend on method of agitation and addition of Freon during the foaming process.Density measurements, viscosity measurements as a function of pH, optical characterization, x-ray crystallography, ultimate compressive strength, dielectric constant measurements and thermal diffusivity were used to characterize these porous SiO2 materials. This paper will discuss the synthetic processes used to develop the porous silicas and properties of these materials.

scholarly journals Structural and Magneto-Optical Characterization of La, Nd: Y2O3 Powders Obtained via a Modified EDTA Sol–Gel Process and HIP-Treated Ceramics

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4928
Author(s):  
Andrzej Kruk
Keyword(s):  
Sol Gel ◽  
Hot Isostatic Pressing ◽  
Rare Earth Ions ◽  
X Ray Diffraction ◽  
Thermal Dependence ◽  
Nanosized Powders ◽  
Verdet Constant ◽  
X Ray ◽  
Sol Gel Process

In this study, pure Y2O3, La0.1Y1.9O3 and La0.1Nd0.12Y1.78O3 nanosized powders were successfully synthesized by a modified sol–gel method. Pure and rare-earth ions doped yttria powders were characterized by X-ray diffraction, scanning electron microscopy and Brunauer–Emmett–Teller methods. The powders were sintered by the hot isostatic pressing process. The highest in-line transmittance of 56% was obtained at 800 nm and increased in the IR region. The influence of the lanthanum and neodymium ions on the physicochemical properties of yttria were discussed. The La-Nd-doped material exhibited a Verdet constant over 4000 deg/T·m at 400 nm and low thermal dependence. An interesting evolution of the Verdet constant across the absorption band with high resolution was studied. A study of the optical and magneto-optical properties of yttria doped with Nd3+ and La3+ is discussed in this paper.

Effect of Mixed-Phase TiO2/PVA Nanofibers on the Degradation on Methyl Orange

2015 ◽  
Vol 1107 ◽  
pp. 353-358
Author(s):  
Norizan Mohammed Lot ◽  
S. Nafisah Md. Rashid ◽  
Umi Sarah Jais ◽  
M. Kamil Abd Rahman
Keyword(s):  
Methyl Orange ◽  
Reaction Rate ◽  
Sol Gel ◽  
Average Diameter ◽  
Mixed Phase ◽  
Electrospinning Technique ◽  
X Ray ◽  
First Order ◽  
Reaction Rate Constants ◽  
Sol Gel Process

We report on the synthesis of nanostructured TiO2for various structural phases and observed the rate of degradation of methyl orange (MO) upon UV irradiation. Mixed phase nanocrystalline TiO2at temperature of 800°C shows higher rate of degradation of MO with the rate of 0.0203/min compared to other phases. This rate corresponds to the percentage of MO degradation of 58.85%, 71.69%, 86.25% and 91.82% for duration of 30, 60, 90 and 120 min of UV irradiations, respectively. The TiO2powder was prepared using titanium (IV) butoxide as the precursor via sol gel process. The samples were characterized using X-ray diffractometer (XRD) and field emission scanning electron microscopy (FESEM). The rate of degradation of MO after UV exposure was measured using UV-Vis spectrophotometer. The first order reaction rate constants (kapp) of anatase; mixed-phase; and rutile phases were 0.0130, 0.0203 and 0.0029, respectively, which shows that mixed-phase TiO2has higherkappvalue indicating higher rate of degradation. The PVA/TiO2nanofibers were produced via electrospinning technique and similar tests on the nanofibers were conducted.Energy dispersive X-ray spectroscopy (EDX) indicates significant presence of TiO2is in nanofibers and the average diameter of the nanofibers was 600 nm.

ELABORATION AND CHARACTERIZATION OF La4Ni3O10 CATHODE MATERIAL (SOFC) BY SOL-GEL PROCESS

2011 ◽  
Vol 1326 ◽  
Author(s):  
Rene Fabian Cienfuegos ◽  
Leonardo Chávez Guerrero ◽  
Sugeheidy Carranza ◽  
Laurie Jouanin ◽  
Guillaume Marie ◽  
...  
Keyword(s):  
Cathode Material ◽  
Sol Gel ◽  
Synthesis Method ◽  
Solid Material ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Metallic Salts ◽  
Sol Gel Process

ABSTRACTThe goal in this study was to synthesize a lanthanum - nickel phase (Ruddlesden-Popper phases) La4Ni3O10. This material was prepared using a polymeric route. An easy synthesis method is presented in order to obtain an economical cathode material, which can be used in Solid Oxide Fuel Cells (SOFC). The polymeric precursors were prepared following the Castillo method. The originality of this work was to optimize the ratio HMTA/ metallic salts from 1 to 6. The obtained powders were characterized by thermal analysis; Differential Scanning Calorimetry (DSC Q10 Instrument TA), Thermogravimetric Analysis (TGA - Q50 Instrument TA-) and X-ray diffractometer (Bruker, D8 Advance diffractometer), in order to determine the crystallized phase. Experiments 5 and 6 did not present coagulation but after few days, solution 5 was transformed into a gel. Gels 2 to 5 were heated in order to obtain a solid material. These powders are characterized by thermogravimetric and thermo-differential methods. The powders obtained at 800, 900 and 1000°C were analyzed by X-ray diffraction and it was found that the temperature to get to the La4Ni3O10 phase was 1000ºC.

Characterization of Medium-range Order in Self-Assembled Organic-inorganic Hybrid by Fluctuation X-ray Microscopy

2006 ◽  
Vol 960 ◽  
Author(s):  
Lixin Fan ◽  
David Paterson ◽  
Ian McNulty ◽  
M. M. J. Treacy ◽  
Dushyant Kumar ◽  
...  
Keyword(s):  
Self Assembly ◽  
Sol Gel ◽  
Range Order ◽  
Inorganic Materials ◽  
Medium Range Order ◽  
X Ray ◽  
Sol Gel Process ◽  
Medium Range ◽  
Self Assembled

ABSTRACTThe control of formation and ordering of self assembled nanostructures, with medium- to long-range order, is a challenge that limits advances in many fields of nanotechnology. We have developed a technique, which we call fluctuation x-ray microscopy, that offers quantitative insight into medium-range correlations in disordered materials at nanometer- and larger-length scales. We examined the influence of sol-gel process variables on medium range order in PI-b-PEO/ aluminosilicate bulk using this technique. The nano-structuring of inorganic materials was directed by polymer self-assembly. The medium range correlation between the nanostructures in two hybrids was quantitatively examined and compared.

Preparation and Characterization of Pr2Ti2O7 by Sol-Gel Process

2017 ◽  
Vol 748 ◽  
pp. 413-417
Author(s):  
Chun Yu Long ◽  
Fang Fang Peng ◽  
Min Min Jin ◽  
Pei Song Tang ◽  
Hai Feng Chen
Keyword(s):  
Methyl Orange ◽  
Single Phase ◽  
Raw Materials ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Illumination Time ◽  
X Ray ◽  
Sol Gel Process ◽  
Ft Ir

Using Pr (NO3)3, butyl titanate, ethylene glycol and citric acid as main raw materials, praseodymium titanate (Pr2Ti2O7) was prepared by the sol-gel process. The samples were characterized by means of X-ray diffraction (XRD), scanning electron microscope (SEM), thermal gravity-differential thermal analysis (TG-DTA), diffuse-reflection spectra (DRS) and Fourier transform infrared (FT-IR). The effect of different calcination temperature and illumination time on the photocatalytic properties of Pr2Ti2O7 was investigated. It was found that the single phase Pr2Ti2O7 could be obtained through sol-gel process and calcination at 1000 °C. The Pr2Ti2O7 samples calcination at 1000 °C were uniform , and the resulting product had a particle size of 200 nm and an optical band gap of 3.26 eV. Under ultraviolet light, the degradation of methyl orange arrived to 80.11% after 180 min of photocatalytic reaction. The Pr2Ti2O7 samples showed good photocatalytic activity for decomposition of methyl orange.

Preparation and Characterization of Sol-Gel Derived Heteroepitaxial LiNbO3 and LiTaO3 Thin Films

1993 ◽  
Vol 310 ◽  
Author(s):  
Keiichi Nashimoto
Keyword(s):  
Thin Films ◽  
Sol Gel ◽  
Metal Alkoxide ◽  
Bulk Single Crystal ◽  
Rocking Curve ◽  
X Ray ◽  
Sapphire Substrates ◽  
Sol Gel Process ◽  
Alkoxide Precursors

AbstractDense epitaxial LiNbO3 thin films without any misoriented plane on sapphire substrates were obtained with a sol-gel process utilizing 2-methoxyethanol based metal alkoxide precursors without pre-hydrolysis and rapid thermal annealing. Epitaxial LiNbO3 films annealed at 700°C were transparent and showed refractive indices close to bulk single crystal values. Epitaxial and transparent LiTaO3 films crystallized successfully on sapphire substrates with single orientations with the present process. X-ray rocking curve full widths at half maximum of epitaxial LiNbO3 and LiTaO3 films on sapphire (110) substrates and annealed at 700°C were less than 0.4 degree.

SYNTHESIS AND CHARACTERIZATION OF Y2SiO5:Ce3+ PHOSPHOR MATERIALS BY SOL–GEL PROCESS

2010 ◽  
Vol 17 (01) ◽  
pp. 59-62 ◽  
Author(s):  
YOUNG-JAE KO ◽  
JONG KYU LEE ◽  
MIN-CHEOL CHU ◽  
DONG-SIK BAE
Keyword(s):  
Electron Microscopy ◽  
Sol Gel ◽  
Synthesis And Characterization ◽  
Luminescence Spectra ◽  
Photoluminescence Spectra ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sol Gel Process ◽  
Scanning Electron

Y 2 SiO 5: Ce 3+ particles was synthesized by sol–gel process. In all samples treated at 1100°C, monoclinic X 1 phase for all cerium concentration. Luminescence spectra shows broad Ce 3+ luminescence in Y 2 SiO 5 host, which picks around 450 nm. The synthesized and calcined powders were characterized by thermogravimetry-differential scanning calorimeter (TG-DSC), X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and photoluminescence spectra (PL).

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