Impedance Analysis and Modulus Spectroscopy of Fe (III) Containing Strontium Stannate Nanoparticles

2016 ◽  
Vol 860 ◽  
pp. 3-6 ◽  
Author(s):  
Ashok Kumar ◽  
Astakala Anil Kumar ◽  
Jitender Kumar Quamara
Keyword(s):  
Sol Gel ◽  
Orthorhombic Phase ◽  
Impedance Analysis ◽  
Ammonium Bromide ◽  
Fe Content ◽  
Modulus Spectroscopy ◽  
Strontium Stannate ◽  
Different Temperatures ◽  
Cetyl Trimethyl Ammonium ◽  
Sol Gel Synthesis

We report the sol-gel synthesis of pristine and Fe containing perovskite structured strontium stannate nanoparticles, stabilized by cetyl trimethyl ammonium bromide (CTAB). The X-ray diffraction data of pristine and Fe doped strontium stannate nanoparticles reveals the formation of orthorhombic phase with Pbnm space symmetry. Raman spectra of pristine and Fe doped SrSnO3 nanoparticles depicts peaks at 220, 256 and 561 corresponding to Sn-O-Sn, O-Sn-O and Sn-O band stretching, respectively. The dc resistivity of pristine and Fe doped SrSnO3 is found to decrease with increase in Fe content. The variation of impedance (Zʹ and Z′′) and electric modulus (Mʹ and M′′) of pristine and Fe doped strontium stannate nanoparticles as a function of frequency (20 Hz to 2 MHz) at different temperatures (310-410 K) has been studied.

scholarly journals Urea-Assisted Synthesis of Mesoporous TiO2 Photocatalysts for the Efficient Removal of Clofibric Acid from Water

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6035
Author(s):  
Lidia Favier ◽  
Amalia Maria Sescu ◽  
Elaziouti Abdelkader ◽  
Laurence Oughebbi Berthou ◽  
Doina Lutic
Keyword(s):  
Sol Gel ◽  
Mesoporous Tio2 ◽  
Clofibric Acid ◽  
Water Remediation ◽  
Ammonium Bromide ◽  
Tio2 Photocatalysts ◽  
Different Temperatures ◽  
Cetyl Trimethyl Ammonium ◽  
Catalyst Reusability ◽  
High Yields

Mesoporous TiO2 photocatalysts intended for the advanced removal of clofibric acid (CA) from water were synthesized by the sol-gel method in a medium containing cetyl-trimethyl-ammonium bromide (CTAB) and urea, using either ethanol or isopropanol to dilute the TiO2 precursor. The activation of the samples was undertaken at 550, 650 and 750 °C. The XRD revealed that the nature of the solvent resulted in significant differences in the anatase-to-rutile ratios obtained at different temperatures. The specific surface area values were situated between 9 and 43 m2g−1 and the band gap values were similar for all the samples. The photocatalytic activity of the prepared samples was examined for the degradation of CA, an emergent water contaminant. The photocatalytic tests performed under UV-A irradiation revealed that the photo-reactivity of these materials depends on the calcination temperature. The best results were obtained for the samples calcined at 750 °C, which showed high yields of CA elimination, as well as almost complete mineralization (over 95%) after 180 min of reaction. Good results in terms of catalyst reusability in the reaction were found for the catalyst showing the highest photo-reactivity. Therefore, the samples can be considered good candidates for future water remediation applications.

Structure and Reactivity of the La2-xSrXMnO4±δ (0.7≤ X ≤1.0) Solid Solutions in Oxidizing Condition

2014 ◽  
Vol 617 ◽  
pp. 98-101
Author(s):  
Thibault Broux ◽  
M. Briand ◽  
C. Prestipino ◽  
Olivier Hernandez ◽  
Mona Bahout
Keyword(s):  
Solid Solutions ◽  
Single Phase ◽  
Sol Gel ◽  
Structural Response ◽  
Orthorhombic Phase ◽  
Structure Type ◽  
Maximum Amount ◽  
Iodometric Titration ◽  
Different Temperatures ◽  
Sol Gel Synthesis

Single phase La2xSrxMnO4±δ (0.7 x 1.0) solid solutions were prepared via sol-gel synthesis. For all the compositions the structure turns out to be tetragonal I4/mmm. Samples were then heated for 12 h at different temperatures in O2 to investigate the structural response to oxygen uptake. On increasing the La/Sr ratio the maximum amount of oxygen inserted (δ) reaches for x = 0.7 an unprecedented value of δ ~ 0.47 in K2NiF4-structure type oxides, as evidenced from iodometric titration and thermogravimetric analysis. For the x 0.8 compositions the oxidation resulted in an intermediate orthorhombic phase.

Mobility of DR1 Molecules Embedded in Nanostructured PMMA Films

2009 ◽  
Vol 5 ◽  
pp. 135-142
Author(s):  
Jorge A. García-Macedo ◽  
A. Franco ◽  
Guadalupe Valverde-Aguilar ◽  
M.A. Ríos-Enríquez
Keyword(s):  
Second Harmonic ◽  
Sodium Dodecyl ◽  
Orientation Distribution ◽  
Decay Rates ◽  
Ammonium Bromide ◽  
X Ray Diffraction ◽  
Poling Field ◽  
Different Temperatures ◽  
Cetyl Trimethyl Ammonium ◽  
Kinetics Of

The kinetics of the orientation of Disperse Red 1 (DR1) molecules embedded in nanostructured Polymethylmetacrylate (PMMA) films was studied under the effect of an intense constant electric poling field. The changes in the orientation distribution of the DR1 molecules were followed by Second Harmonic Generation (SHG) measurements. The SHG signal was recorded as function of time at three different temperatures. We focused on both, the signal increases under the presence of the poling field and the signal decays without the poling field. The studied PMMA films were nanostructured by the incorporation of ionic surfactants as the Sodium Dodecyl Sulfate (SDS) and the Cetyl Trimethyl Ammonium Bromide (CTAB) during their preparation. The kinds of nanostructures obtained in the films were determined by means of X-ray diffraction (XRD) measurements. Substantial differences in signal intensity and in growth and decay rates between amorphous and nanostructured films were found.

Experimental and Theoretical Studies of Thermophysical Properties of MgO-Water Nanofluid

2020 ◽  
Vol 1008 ◽  
pp. 47-52
Author(s):  
Abdallah Yousef Mohammed Ali ◽  
Ahmed Hassan El-Shazly ◽  
Marwa Farouk El-Kady ◽  
Hesham Ibrahim Elqady ◽  
Kholoud Madih ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermophysical Properties ◽  
Volume Fraction ◽  
Sol Gel ◽  
Solid Volume Fraction ◽  
Ammonium Bromide ◽  
Distilled Water ◽  
Step Method ◽  
Mgo Nanoparticles ◽  
Cetyl Trimethyl Ammonium

Magnesium oxide (MgO) nanoparticles were synthesized using the sol-gel technique then characterized. Cetyl Trimethyl Ammonium Bromide (CTAB) surfactant was added to reduce Van der Waal forces among MgO nanoparticles and distilled water forming a stable nanofluid using two-step method with aid of ultrasound sonication. Pure distilled water and nanofluids with different volume fractions of 0.25, 0.5, 0.75, and 1% are used as working fluids. Thermophysical properties of prepared nanofluids were measured experimentally and determined theoretically. Effect of solid volume fraction on the thermophysical properties; including thermal conductivity, heat capacity, viscosity, and density of MgO-water nanofluids are discussed. Moreover, experimental results have been compared with the suitable correlations for MgO-water nanofluid. The findings show that thermal conductivity, viscosity, and density of nanofluid increases with increasing solid volume fraction.

Study of Pseudoboehmite Synthesis by Sol-Gel Process

2006 ◽  
Vol 45 ◽  
pp. 260-265 ◽  
Author(s):  
Antônio Hortêncio Munhoz Jr. ◽  
Leila Figueiredo de Miranda ◽  
G.N. Uehara
Keyword(s):  
Sol Gel ◽  
Thermo Gravimetric Analysis ◽  
Ammonium Hydroxide ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Sol Gel Process ◽  
Different Temperatures ◽  
Sol Gel Synthesis

A pseudoboehmite was obtained by sol-gel synthesis using aluminum nitrate as precursor. It was used a 2n full factorial design for studying the effect of the temperature of synthesis, the concentration of ammonium hydroxide, and the radiation dose in the product of sol-gel synthesis. The product of the synthesis was analyzed by scanning electron microscopy, x-ray diffraction of the product (after firing the pseudoboehmite at different temperatures), and it was also analyzed the temperature of endothermic and exothermic transformations using the thermo gravimetric analysis (TG) and differential scanning calorimetry (DSC). The X-ray diffraction data show that α-alumina was obtained at 1100o C.

AP40 Bioactive Glass Ceramic by Sol-Gel Synthesis: In Vitro Dissolution and Cell-Mediated Bioresorption

2013 ◽  
Vol 541 ◽  
pp. 41-50 ◽  
Author(s):  
Ilaria Cacciotti ◽  
Giorgia Lehmann ◽  
Antonella Camaioni ◽  
Alessandra Bianco
Keyword(s):  
Bioactive Glass ◽  
Human Peripheral Blood ◽  
Sol Gel ◽  
Blood Monocytes ◽  
X Ray Diffraction ◽  
Degradation Behaviour ◽  
Dissolution Tests ◽  
Different Temperatures ◽  
Sol Gel Synthesis

In this work, the sol-gel synthesis of AP40 bioactive glass system was reported. The obtained powder was fully characterised in terms of microstructure, composition and thermal behaviour by X-ray diffraction (XRD) measurements, Fourier transform infrared (FT-IR) spectroscopy, thermogravimetry and differential thermal analysis (TG-DTA).In vitrodissolution tests were performed in order to assess the degradation behaviour of sol-gel derived AP40 samples thermally treated at different temperatures. Finally, preliminary results on cytocompatibility are reported, based on bioresorption activity of human peripheral blood monocytes differentiated into osteoclasts on sintered disks.

scholarly journals Preparation and photocatalytic activity analysis of nanometer TiO2 modified by surfactant

2018 ◽  
Vol 8 ◽  
pp. 184798041878197 ◽  
Author(s):  
Wenzheng Wu ◽  
Longjian Zhang ◽  
Xiaojie Zhai ◽  
Ce Liang ◽  
Kaifeng Yu
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Anatase Phase ◽  
Sol Gel ◽  
Sodium Dodecyl ◽  
Sodium Dodecyl Benzene Sulfonate ◽  
Ammonium Bromide ◽  
Transmission Electron ◽  
Cetyl Trimethyl Ammonium ◽  
Nano Titanium Dioxide

Combining the advantages of the sol–gel method and solvothermal method, the single anatase phase of nano-titanium dioxide (TiO2) with high crystallinity had been prepared by means of the sol–solvent thermal improved process, in which butyl titanate was used as titanium source; anhydrous ethanol as solvent; concentrated nitric acid as inhibitor; and cationic surfactant cetyl trimethyl ammonium bromide (CTAB), anionic surfactant sodium dodecyl benzene sulfonate (SDBS), and nonionic surfactant polyethylene glycol (PEG) as dispersants. The analysis results of Brunauer–Emmett–Teller, scanning electron microscopy, and transmission electron microscopy characterizations indicated that CTAB-modified TiO2 with the optimum ratio had the most apparent dispersibility and the highest specific surface area compared with unmodified TiO2, SDBS-modified TiO2, and PEG-modified TiO2. At the same time, the photocatalytic degradation rate of methyl orange could be improved to 99.16%. It indicated that the modification effect of CTAB was significantly better than those of SDBS and PEG, which made the nanoparticles uniformly dispersed, resulting in higher photocatalytic activity.

scholarly journals Sol-gel synthesis of zinc oxide nanoparticle at three different temperatures and its characterization via XRD, IR and EPR

DYNA ◽  
2016 ◽  
Vol 83 (195) ◽  
pp. 224-228 ◽  
Author(s):  
Manuel Fernando Acosta Humánez ◽  
Luis Alfredo Montes Vides ◽  
Ovidio Amado Almanza-Montero
Keyword(s):  
Zinc Oxide ◽  
Crystallite Size ◽  
Rietveld Method ◽  
Sol Gel ◽  
Oxide Phase ◽  
Cell Types ◽  
Paramagnetic Resonance ◽  
Calcination Temperatures ◽  
Different Temperatures ◽  
Sol Gel Synthesis

In this work, nanoparticles of zinc oxide were synthesized; they were formed using the sol-gel method (citrate route) at calcination temperatures (Tc) of 500, 550 and 600 °C. For all samples studied, IR spectroscopy showed the presence of the bands associated with water molecules present in the zinc oxide and carbon dioxide adsorbed on its surface. The formation of zinc oxide phase was confirmed by XRD, which showed that from 500 ºC it had this type of Wurtzite structure. However, samples calcinated at 600 ºC have higher crystallinity. Crystallite size was calculated using the Scherrer equation. The Rietveld method was used to obtain lattice parameters a and c for Wurtzite cell types as well as cell volume and the ratio c/a of each sample. These parameters do not show significant changes when they are compared with values obtained from samples with different calcination temperatures. Electron paramagnetic resonance showed the presence of defects in the zinc oxide. Three signals with g values of 1.96, 2.00 and 2.04 were associated with oxygen and zinc vacancies. Defects in the structure disappear when the calcination temperature is increased. The sample that was highlighted with the highest concentration of vacancies has a mean crystallite size greater than 30 nm, and this may also be responsible for this feature.

Preparation, Characterization and Catalytic Activity of Sulfated Zirconia by Varied Sol-Gel Method

2015 ◽  
Vol 1123 ◽  
pp. 96-99
Author(s):  
Is Fatimah ◽  
Zulfa Zuhrufa
Keyword(s):  
Catalytic Activity ◽  
Surface Area ◽  
Sulfated Zirconia ◽  
Sol Gel ◽  
Acid Catalyst ◽  
Bet Surface Area ◽  
Ammonium Bromide ◽  
Templating Method ◽  
Prepared Material ◽  
Sol Gel Synthesis

The sulfated zirconia catalysts were was prepared by sol–gel processes consist of varied templating method. Both preparations consist of sol-gel synthesis of zirconium dioxide followed by sulfatation process by using NH4SO4solid reaction method. Two different templating agent; urea and cetyltrimetyl ammonium bromide was used in sol-gel processes. The prepared material was characterized using scanning electron microscope (SEM), x-ray diffraction (XRD) and Brunauer–Emmett–Teller (BET) measurements. From the XRD measurement it can be concluded that both materials consist of ZrO2in combined phases while from BET surface area analysis it can be noted that material prepared by urea template has higher specific surface area compared to that use CTAB template. Both materials exhibit the activity as acid catalyst in microwave assisted conversion of citronellal. It is also confirmed that the higher the surface area the higher total conversion of citronellal obtained. Study on the correlation between physicochemical properties of materials with the catalytic activity was discussed in this paper.

scholarly journals Effect of the Microstructure of the Semiconductor Support on the Photocatalytic Performance of the Pt-PtOx/TiO2 Catalyst System

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 943
Author(s):  
Katalin Majrik ◽  
Zoltán Pászti ◽  
László Korecz ◽  
Judith Mihály ◽  
Zoltán May ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Photocatalytic Performance ◽  
Sol Gel ◽  
Catalyst System ◽  
Structural Features ◽  
H2 Production ◽  
X Ray ◽  
Preparation Conditions ◽  
Different Temperatures ◽  
Sol Gel Synthesis

The influence of the semiconductor microstructure on the photocatalytic behavior of Pt-PtOx/TiO2 catalysts was studied by comparing the methanol-reforming performance of systems based on commercial P25 or TiO2 from sol–gel synthesis calcined at different temperatures. The Pt co-catalyst was deposited by incipient wetness and formed either by calcination or high-temperature H2 treatment. Structural features of the photocatalysts were established by X-ray powder diffraction (XRD), electron spin resonance (ESR), X-ray photoelectron spectroscopy (XPS), optical absorption, Raman spectroscopy and TEM measurements. In situ reduction of Pt during the photocatalytic reaction was generally observed. The P25-based samples showed the best H2 production, while the activity of all sol–gel-based samples was similar in spite of the varying microstructures resulting from the different preparation conditions. Accordingly, the sol–gel-based TiO2 has a fundamental structural feature interfering with its photocatalytic performance, which could not be improved by annealing in the 400–500 °C range even by scarifying specific surface area at higher temperatures.

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