scholarly journals A versatile bio-inspired material platform for catalytic applications: micron-sized “buckyball-shaped” TiO2structures

RSC Advances ◽  
2015 ◽  
Vol 5 (58) ◽  
pp. 47174-47182 ◽  
Author(s):  
Deniz Altunoz Erdogan ◽  
Touradj Solouki ◽  
Emrah Ozensoy
Keyword(s):  
Sol Gel ◽  
Synthesis Method ◽  
Lycopodium Clavatum ◽  
Naturally Occurring ◽  
Catalytic Applications ◽  
Sol Gel Synthesis

A simple sol–gel synthesis method is presented for the production of micron-sized buckyball-like TiO2architectures using naturally occurringLycopodium clavatum(LC) spores as biotemplates.

scholarly journals Aqueous Sol-Gel Synthesis of Different Iron Ferrites: From 3D to 2D

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1554
Author(s):  
Justinas Januskevicius ◽  
Zivile Stankeviciute ◽  
Dalis Baltrunas ◽  
Kęstutis Mažeika ◽  
Aldona Beganskiene ◽  
...  
Keyword(s):  
Magnetic Measurements ◽  
Substrate Surface ◽  
Sol Gel ◽  
Synthesis Method ◽  
Xrd Analysis ◽  
Dip Coating ◽  
Yttrium Iron ◽  
Iron Garnet ◽  
Dip Coating Technique ◽  
Sol Gel Synthesis

In this study, an aqueous sol-gel synthesis method and subsequent dip-coating technique were applied for the preparation of yttrium iron garnet (YIG), yttrium iron perovskite (YIP), and terbium iron perovskite (TIP) bulk and thin films. The monophasic highly crystalline different iron ferrite powders have been synthesized using this simple aqueous sol-gel process displaying the suitability of the method. In the next step, the same sol-gel solution was used for the fabrication of coatings on monocrystalline silicon (100) using a dip-coating procedure. This resulted, likely due to substrate surface influence, in all coatings having mixed phases of both garnet and perovskite. Thermogravimetric (TG) analysis of the precursor gels was carried out. All the samples were investigated by X-ray powder diffraction (XRD) analysis. The coatings were also investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM) and Mössbauer spectroscopy. Magnetic measurements were also carried out.

scholarly journals Sol-Gel Synthesis of the Double Perovskite Sr2FeMoO6 by Microwave Technique

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3876
Author(s):  
Jesús Valdés ◽  
Daniel Reséndiz ◽  
Ángeles Cuán ◽  
Rufino Nava ◽  
Bertha Aguilar ◽  
...  
Keyword(s):  
Particle Size ◽  
Hydrothermal Synthesis ◽  
Microwave Radiation ◽  
Structural Characteristics ◽  
Sol Gel ◽  
Synthesis Method ◽  
Double Perovskite ◽  
Synthesis Methods ◽  
X Ray ◽  
Sol Gel Synthesis

The effect of microwave radiation on the hydrothermal synthesis of the double perovskite Sr2FeMoO6 has been studied based on a comparison of the particle size and structural characteristics of products from both methods. A temperature, pressure, and pH condition screening was performed, and the most representative results of these are herein presented and discussed. Radiation of microwaves in the hydrothermal synthesis method led to a decrease in crystallite size, which is an effect from the reaction temperature. The particle size ranged from 378 to 318 nm when pH was 4.5 and pressure was kept under 40 bars. According to X-ray diffraction (XRD) results coupled with the size-strain plot method, the product obtained by both synthesis methods (with and without microwave radiation) have similar crystal purity. The Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS) techniques showed that the morphology and the distribution of metal ions are uniform. The Curie temperature obtained by thermogravimetric analysis indicates that, in the presence of microwaves, the value was higher with respect to traditional synthesis from 335 K to 342.5 K. Consequently, microwave radiation enhances the diffusion and nucleation process of ionic precursors during the synthesis, which promotes a uniform heating in the reaction mixture leading to a reduction in the particle size, but keeping good crystallinity of the double perovskite. Precursor phases and the final purity of the Sr2FeMoO6 powder can be controlled via hydrothermal microwave heating on the first stages of the Sol-Gel method.

Effect of sol–gel synthesis method on the structural, electrical, and ferroelectric properties of lead-free K0.5Na0.5NbO3 ceramic

2019 ◽  
Vol 92 (1) ◽  
pp. 215-223 ◽  
Author(s):  
Shammi Kumar ◽  
Mamta Shandilya ◽  
Shweta Thakur ◽  
Nagesh Thakur ◽  
Gun Anit Kaur
Keyword(s):  
Ferroelectric Properties ◽  
Sol Gel ◽  
Synthesis Method ◽  
Lead Free ◽  
Sol Gel Synthesis

scholarly journals Nanoscale CaF2 doped with Eu3+ and Tb3+ through fluorolytic sol–gel synthesis

2014 ◽  
Vol 2 (40) ◽  
pp. 8607-8613 ◽  
Author(s):  
Benjamin Ritter ◽  
Thoralf Krahl ◽  
Knut Rurack ◽  
Erhard Kemnitz
Keyword(s):  
Room Temperature ◽  
Sol Gel ◽  
Synthesis Method ◽  
One Pot ◽  
One Pot Synthesis ◽  
Sol Gel Synthesis

Easy upscaleable one-pot synthesis method at room temperature for ultra small sized Eu3+- and Tb3+-doped CaF2 nanoparticles.

One-pot sol-gel synthesis of sulfated ZrO2-SiO2 catalysts for alcohol dehydration

2001 ◽  
Vol 79 (8) ◽  
pp. 1220-1223 ◽  
Author(s):  
Quan Zhuang ◽  
Jack M Miller
Keyword(s):  
Ammonium Sulfate ◽  
Sulfated Zirconia ◽  
Sol Gel ◽  
Synthesis Method ◽  
Acid Catalyst ◽  
Alcohol Dehydration ◽  
One Pot ◽  
Zirconium Propoxide ◽  
The One ◽  
Sol Gel Synthesis

Sulfated ZrO2–SiO2 catalysts were synthesized by one-pot sol-gel method using ammonium sulfate, zirconium propoxide, and tetraethyl orthosilicate as precursors. The catalysts were characterized by N2 adsorption and DRIFTS. On calcining the gel at elevated temperature, the ammonium sulfate decomposed, giving a sulfated zirconia–silica catalyst. By adding ammonium sulfate to the sol-gel synthesis system, the surface area, pore size, and pore volume of the resultant catalyst were increased. The one-pot sol-gel synthesized catalyst with an optimum loading of SO42– 14 mol% showed significantly higher catalytic activity, with a selectivity of 100%, for isopropanol dehydration when compared to the impregnated catalyst. The one-pot sol-gel synthesis method is an effective way to prepare sulfated zirconia catalyst.Key words: sulfated zirconia, sol-gel synthesis, acid catalyst, alcohol dehydration, N2 adsorption, DRIFT.

scholarly journals Effect of the Gallium and Vanadium on the Dibenzothiophene Hydrodesulfurization and Naphthalene Hydrogenation Activities Using Sulfided NiMo-V2O5/Al2O3-Ga2O3

Catalysts ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 894 ◽  
Author(s):  
Esneyder Puello-Polo ◽  
Yina Pájaro ◽  
Edgar Márquez
Keyword(s):  
Elemental Analysis ◽  
Rate Constants ◽  
Active Sites ◽  
Sol Gel ◽  
Synthesis Method ◽  
Textural Properties ◽  
Elemental Mapping ◽  
Sulfided Catalysts ◽  
Nimo Catalysts ◽  
Sol Gel Synthesis

The effect of Ga and V as support-modifier and promoter of NiMoV/Al2O3-Ga2O3 catalyst on hydrogenation (HYD) and hydrodesulfurization (HDS) activities was studied. The catalysts were characterized by elemental analysis, textural properties, XRD, XPS, EDS elemental mapping and High-resolution transmission electron microscopy (HRTEM). The chemical analyses by X-ray Fluorescence (XRF) and CHNS-O elemental analysis showed results for all compounds in agreement, within experimental accuracy, according to stoichiometric values proposed to Mo/Ni = 6 and (V+Ni)/(V+Ni+Mo) = 0.35. The sol-gel synthesis method increased the surface area by incorporation of Ga3+ ions into the Al2O3 forming Ga-O-Al bonding; whereas the impregnation synthesis method leads to decrease by blocking of alumina pores, as follows NiMoV/Al-Ga(1%-I) < NiMoV/Al-Ga(1%-SG) < NiMo/Al2O3 < Al2O3-Ga2O3(1%-I) < Al2O3-Ga2O3(1%-SG) < Al2O3, propitiating Dp-BJH between 6.18 and 7.89 nm. XRD confirmed a bulk structure typical of (NH4)4[NiMo6O24H6]•5H2O and XPS the presence at the surface of Mo4+, Mo6+, NixSy, Ni2+, Ga3+ and V5+ species, respectively. The EDS elemental mapping confirmed that Ni, Mo, Al, Ga, V and S are well-distributed on Al2O3-Ga2O3(1%-SG) support. The HRTEM analysis shows that the length and stacking distribution of MoS2 crystallites varied from 5.07 to 5.94 nm and 2.74 to 3.58 with synthesis method (SG to I). The results of the characterization sulfided catalysts showed that the synthesis method via impregnation induced largest presence of gallium on the surface influencing the dispersion V5+ species, this effect improves the dispersion of the MoS2 phase and increasing the number of active sites, which correlates well with the dibenzothiophene HDS and naphthalene HYD activities. The dibenzothiophene HDS activities with overall pseudo-first-order rate constants’ values (kHDS) from 1.65 to 7.07 L/(h·mol·m2) follow the order: NiMoV-S/Al-Ga(1%-I) < NiMo-S/Al2O3 < NiMoV-S/Al-Ga(1%-SG), whereas the rate constants’ values (k) of naphthalene HYD from 0.022 to 2.23 L/(h·mol·m2) as follow: NiMoV-S/Al-Ga(1%-SG) < NiMo-S/Al2O3 < NiMoV-S/Al-Ga(1%-I). We consider that Ga and V act as structural promoters in the NiMo catalysts supported on Al2O3 that allows the largest generation of BRIM sites for HYD and CUS sites for DDS.

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.

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