Showing papers on "Sol-gel published in 2021"
TL;DR: In this paper, the structure and magnetization of polycrystalline Zn1−xMnxO3 films grown on glass and Si substrates using Sol-Gel technique have been studied.
Abstract: The structure and magnetization of polycrystalline Zn1−xMnxO3 films (
$$0 \le x \le 0.1)$$
grown on glass and Si substrates using Sol–Gel technique have been studied. The average grain sizes of between 20 and 30 nm for nano-sphere structured polycrystalline samples grown on the glass substrate have been obtained in a result of X-ray diffraction analysis. Changes in the structural parameters by the increase in Mn content have been observed. Average grain sizes and porosities of the samples have been obtained from SEM studies. It has been revealed that the films grown on glass substrates did not exhibit ferromagnetic order even after thermal treatment. On the contrary, Zn1−xMnxO3 films with Mn contents of x = 0.05 and 0.10 grown on Si substrate exhibited ferromagnetic properties after thermal annealing. This phenomenon has been interpreted on the base of the existence of carrier mediated magnetic ordering in Zn1−xMnxO3 diluted magnetic semiconductors. In a result, a procedure of thermal treatment is suggested for achieving of the room temperature ferromagnetism in Mn doped ZnO films synthesized on p-type Si substrates for their applications as magnetic semiconductor material in spintronic devices.
34 citations
01 Apr 2021
TL;DR: In this paper, the fabrications of undoped LaCrO3 and Ni2+, Fe3+, Co2+ and Co2 + nano-coated nano-structural properties of the spin coating of the pre-processed nano-composition of the nanostructures were reported by using the sol-gels prepared for these thin film samples.
Abstract: In this study, we are reporting the fabrications of undoped LaCrO3 and Ni2+, Fe3+, Co2+ modified LaCrO3 thin films by spin coating method using the sol-gels prepared for these thin film samples The structural properties of the spin coated LaCrO3 thin films measured by X-ray diffractometer (XRD), which confirms the formation of orthorhombic LaCrO3 nanoparticles The morphological properties of the prepared films were investigated by the ease of scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HR-TEM) where the orthorhombic and crystalline LaCrO3 nanoparticles were observed Energy dispersive x-ray analysis (EDAX) was utilized for the determination of elemental composition The prepared material was found be in perfect elemental composition The surface area and BJH pore distribution was observed by Brunauer-Emmett-Teller (BET) analysis The Ni2+, Fe3+, Co2+modified LaCrO3 thin film found with high surface area of 8632 m2/g Optical properties of both prepared materials investigated by ultraviolet differential reflectance spectroscopy (UV-DRS) to compare band gap energy of prepared sensors It is observed that due to modification of transition metals, band gap energy of modified LaCrO3 sensor is found to be declined The electrical properties were carried out to confirm semiconducting behaviour of LaCrO3 semiconductor The thin films were subjected for gas sensing study of CO, CO2, NO2, LPG, toluene vapours and petrol vapours The modified LaCrO3 sensor found to be highly sensitive for CO2, CO, and NO2 gases with response 8214 (300 °C), 7452 (200 °C) and 6518% (150 °C) respectively The relative humidity from 10 to 90% at 20 Hz found to be efficient for modified LaCrO3 sensor In summary it can stated that transition metal doping successful to tune the band gap energy, porosity and surface area of modified LaCrO3 sensor Due to this the sensor properties such as% response,% selectivity, response recovery, reusability and humidity sensing performance found to enhance for modified LaCrO3 sensor
27 citations
TL;DR: In this paper, the authors demonstrate the synthesis and the investigation of magnetostatic and magnetodynamic properties of epsilon iron oxide (e-Fe2O3) nanoparticles of various sizes.
Abstract: In this study, we demonstrate the synthesis and the investigation of magnetostatic and magnetodynamic properties of epsilon iron oxide (e-Fe2O3) nanoparticles of various sizes. Silica gels were obtained by rapid hydrolysis of tetraethoxysilane in an aqueous–alcoholic solution of iron(III) nitrate and then dried to form xerogels. The annealing of the xerogels at temperatures of 1000–1250 °C led to the formation of e-Fe2O3 particles with average sizes of 7–38 nm, respectively. With an increase in the annealing temperature, the coercivity of the samples increased and reached 21 kOe for 1200 °C, while the frequency of the natural ferromagnetic resonance increased from 161 to 170 GHz followed by narrowing of the absorption lines from 40 to 2 GHz. It was shown for the first time that the parameters of the natural ferromagnetic resonance line of epsilon iron oxide can be varied by controlling the size of e-Fe2O3 particles. It was also demonstrated that the duration of e-Fe2O3 synthesis can be considerably reduced by increasing the rate of tetraethoxysilane hydrolysis, while the magnetic properties of the target material do not degrade.
26 citations
TL;DR: In this paper, a SiC-B4C nano powders were synthesized through sol-gel process in water-solvent-catalyst-dispersant system, where TEM, SEM, DTA/TG, BET, XRD, FTIR and DLS analysis methods were employed.
23 citations
TL;DR: In this article, the effect of Mg dopant on the structural, surface-morphological, and optical properties of ZnO thin films was investigated using sol-gel dip-coating technique.
Abstract: Undoped ZnO and Mg-doped ZnO (MZO) thin films were synthesized by sol–gel dip-coating technique. The effect of Mg dopant on the structural, surface-morphological, and optical properties together wi...
21 citations
TL;DR: The sol-gel method is a simple and low-cost technique that requires low temperature for the reaction process as mentioned in this paper, which has been used in a variety of applications, including corrosion prevention, biomedical applications, and electronic devices.
18 citations
TL;DR: In this article, a two-step Sol-gel reaction with a fast ambient pressure drying process was used to synthesize thermal insulating hydrophobic silica aerogel powder, which exhibits excellent properties, such as low apparent density (0.212 kg/cm3), thermal conductivity ( 0.053 W/mK), high BET surface area (769.86 m2/g), and water contact angle (149.0 °).
Abstract: This paper proposed a timesaving route for preparing silica aerogel powder with TEOS as a precursor. Thermal insulating super hydrophobic silica aerogel powder was synthesized by combining two-step Sol-gel reaction with a fast ambient pressure drying process. Silica Sol-gel was formed after catalytic reaction by oxalic acid and NH4OH, and then turned to be hydrophobic aerogel through further surface modification (only three hours with no solvent exchange process) and drying process. By optimizing every tiny trace of synthetic component, the obtained silica aerogel powder exhibits excellent properties, such as low apparent density (0.212 g/cm3) and thermal conductivity (0.053 W/mK), as well as high BET surface area (769.86 m2/g) and water contact angle (149.0 °). This work presents a timesaving method for synthesizing thermal insulating hydrophobic silica aerogel powder.
18 citations
DOI•
25 Nov 2021
TL;DR: In this article, metal oxide titanium dioxide (TiO2) nanoparticles were synthesized by using a simple and economical sol-gel method and used as catalysts in the oxidation of benzaldehyde.
Abstract: Metal oxide titanium dioxide (TiO2) nanoparticles were synthesized by using a simple and economical sol-gel method. The prepared nanoparticles were used to evaluate methylene blue dye degradation and as catalysts in the oxidation of benzaldehyde. The crystallite size of the titanium dioxide nanoparticle was 18.3 nm, which was confirmed by X-ray diffraction analysis. The spherical morphology was confirmed by scanning electron microscopy (SEM), and the elemental composition of the nanoparticle was found by energy dispersive X-ray (EDAX) analysis. The anatase form of the nanoparticle was confirmed by the bandgap 3.2 eV, which was measured using UV–DRS analysis. The bond between metal and oxygen was confirmed by the peaks at 485 and 606 cm–1 analyzed by Fourier transform infrared analysis (FTIR). The efficiency of the catalyst in dye degradation was 60.08, 68.38, and 80.89% with respect to 50, 75, and 100 mg catalyst weight. The yield % of benzoic acid was 94%, and the reduction efficiency against 4-nitrophenol was 98.44%.
17 citations
TL;DR: In this paper, a facile sol-gel technique was successfully employed to prepare CaCu3-xSexTi4O12 (x ǫ = 0, 0.1, 0.,2, 0, 3, 4) nanoparticles and after subsequent calcination and sintering at 950 and 1050°C respectively, ceramics of these nanoparticles were obtained.
16 citations
TL;DR: In this paper, the optical, structural, morphological, electrochemical and electrochromic properties of the prepared WO3 films were studied, and a five layered EC windows were developed and studied with Li+ and H+ conducting gel electrolytes.
15 citations
TL;DR: In this paper, 8-hydroxyquinoline (8-HQ) intercalated layered double hydroxides (LDH) film as underlayer and sol-gel layer was combined for active corrosion protection of the AM60B magnesium alloy.
Abstract: 8-hydroxyquinoline (8-HQ) intercalated layered double hydroxides (LDH) film as underlayer and sol—gel layer was combined for active corrosion protection of the AM60B magnesium alloy. The LDH, LDH/sol—gel, and LDH@HQ/sol—gel coatings were analyzed using the scanning electron microscopy (SEM), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), atomic force microscopy (AFM), and electrochemical impedance spectroscopy (EIS) methods. The SEM images showed that the surface was entirely coated by the LDH film composed of vertically-grown nanosheets. The same morphology was observed for the LDH/sol—gel and LDH@HQ/sol—gel coatings. Also, almost the same topography was observed for both composite coatings except that the LDH@HQ/sol—gel coating had relatively higher surface roughness. Although the LDH film had the same impedance behavior as the alloy sample in 3.5wt% NaCl solution, its corrosion resistance was much higher, which could be due to its barrier properties as well as to the trapping of the chloride ions. Similar to the LDH film, the corrosion resistance of the LDH/sol—gel composite diminished with increasing the exposure time. However, its values were much higher than that of the LDH film, which was mainly related to the sealing of the solution pathways. The LDH@HQ/sol—gel composite showed much better anti-corrosion properties than the LDH/sol—gel coating due to the adsorption of the 8-HQ on the damaged areas through the complexation.
TL;DR: In this paper, the authors reported the synthesis of copper oxide (CuO) thin films by sol-gel process assisted by spin coating technique at room temperature using a spectrophotometer (UV-vis-NIR) in a range of 300−1100
TL;DR: In this article, a sol-gel method to synthesize and characterize ZnFe2O4 nanoparticles was reported, where the nanoparticles were synthesized by sintering the xerogel following a low-temperature drying method.
TL;DR: In this paper, a hybrid sol-gel super-hydrophobic coatings based on alkyl silane-modified nanosilica were synthesized and studied using the classic Stober process for producing hydrophilic silica nanoparticles.
Abstract: Hybrid sol–gel superhydrophobic coatings based on alkyl silane-modified nanosilica were synthesized and studied. The hybrid coatings were synthesized using the classic Stober process for producing hydrophilic silica nanoparticles (NPs) modified by the in-situ addition of long-chain alkyl silanes co-precursors in addition to the common tetraethyl orthosilicate (TEOS). It was demonstrated that the long-chain alkyl substituent silane induced a steric hindrance effect, slowing the alkylsilane self-condensation and allowing for the condensation of the TEOS to produce the silica NPs. Hence, following the formation of the silica NPs the alkylsilane reacted with the silica’s hydroxyls to yield hybrid alkyl-modified silica NPs having superhydrophobic (SH) attributes. The resulting SH coatings were characterized by contact angle goniometry, demonstrating a more than 150° water contact angle, a water sliding angle of less than 5°, and a transmittance of more than 90%. Confocal microscopy was used to analyze the micro random surface morphology of the SH surface and to indicate the parameters related to superhydrophobicity. It was found that a SH coating could be obtained when the alkyl length exceeded ten carbons, exhibiting a raspberry-like hierarchical morphology.
TL;DR: In this article, a particle size distribution of e-Fe2O3 nanoparticles from 3.5 to 46±0.8 nm was found in an amorphous silica matrix, and three octahedral and one tetrahedral sites were identified for e-phase.
TL;DR: In this article, the authors deal with sol-gel derived SnO2-TiO2 thin films deposited on silicon wafer type Si (1.0) substrate, which are processed by spin coating technique, and the first characterization via XRD identifies the nano-crystalline phase begins to form at 400°C from the long range order and becomes well crystallized into larger size with annealing temperature.
TL;DR: In this paper, nano-nanosized zinc oxide (ZnO) particles modified with different silane coupling agents were synthesized in basic catalysis using the sol-gel method.
Abstract: Nanosized zinc oxide (ZnO) particles modified with different silane coupling agents (octyltriethoxysilane (OTES), octadecyltriethoxysilane (ODTES) and (3-glycidyloxypropyl)trimethoxysilane (GPTMS)) were synthesized in basic catalysis using the sol-gel method. The structure and morphology were characterized by dynamic light scattering (DLS), environmental scanning electron microscopy (ESEM) and Fourier transform infrared spectroscopy (FTIR) for bonding characteristics. The final hybrid materials were deposited on three types of metallic substrates (aluminum (Al), copper (Cu) and zinc (Zn)) in order to obtain coatings with ultrahydrophobic and anti-corrosion properties. Water wettability was studied revealing a contact angle of 145° for the surface covered with ZnO material modified with ODTES. The water contact angle increased with the length of the alkyl chain supplied by the silica precursor. The anti-corrosive behavior of ZnO/silane coupling agents particles deposited on metallic substrates was studied by the linear polarization technique in neutral medium.
TL;DR: In this article, the authors reported the application of sol-gel method for the preparation of a new type of highly active Al2O3-2SiO2 geopolymer precursor powder, which was characterized by SEM, XRD, TG, FTIR and MAS NMR.
TL;DR: In this paper, a novel high-k hybrid material synthesized at low temperature using a simple sol-gel derived method compatible with organic large-area application is reported, where the homogeneous cross-linked organic-inorganic dielectric film is achieved by solution process and densified at 100 °C.
TL;DR: In this article, the authors reported highly uniform copper (Cu) and zinc oxide (ZnO) anchored SiO2 synthesized by facile sol-gel method, which showed high specific capacitance of 423 F g−g−1 and 227.5 f g−1 for SiO 2 −Cu and SiO 1 −Zn O at 4
TL;DR: In this paper, the characterization of ZrO2 thin films synthesized by the sol-gel method, using two different routes, is presented, where thin films were deposited by dip-coating on glass and Zircaloy-4 (Zry-4) substrates, and heat treated at 500°C under atmospheric air.
TL;DR: In this article, a thin film of Zn3(PO4)2/CNT composite thin film was fabricated on glass substrate by the simple sol-gel drop coating method, and the crystal structure, particle size, morphology and optical properties were characterized by X-ray Diffraction, Field Emission Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy (FT-IR) and Ultraviolet-visible Spectrograph.
TL;DR: In this article, an eco-friendly process for producing TiO2 via colloidal aqueous sol-gel synthesis, resulting in crystalline materials without a calcination step, is presented.
Abstract: This work reviews an eco-friendly process for producing TiO2 via colloidal aqueous sol–gel synthesis, resulting in crystalline materials without a calcination step. Three types of colloidal aqueous TiO2 are reviewed: the as-synthesized type obtained directly after synthesis, without any specific treatment; the calcined, obtained after a subsequent calcination step; and the hydrothermal, obtained after a specific autoclave treatment. This eco-friendly process is based on the hydrolysis of a Ti precursor in excess of water, followed by the peptization of the precipitated TiO2. Compared to classical TiO2 synthesis, this method results in crystalline TiO2 nanoparticles without any thermal treatment and uses only small amounts of organic chemicals. Depending on the synthesis parameters, the three crystalline phases of TiO2 (anatase, brookite, and rutile) can be obtained. The morphology of the nanoparticles can also be tailored by the synthesis parameters. The most important parameter is the peptizing agent. Indeed, depending on its acidic or basic character and also on its amount, it can modulate the crystallinity and morphology of TiO2. Colloidal aqueous TiO2 photocatalysts are mainly being used in various photocatalytic reactions for organic pollutant degradation. The as-synthesized materials seem to have equivalent photocatalytic efficiency to the photocatalysts post-treated with thermal treatments and the commercial Evonik Aeroxide P25, which is produced by a high-temperature process. Indeed, as-prepared, the TiO2 photocatalysts present a high specific surface area and crystalline phases. Emerging applications are also referenced, such as elaborating catalysts for fuel cells, nanocomposite drug delivery systems, or the inkjet printing of microstructures. Only a few works have explored these new properties, giving a lot of potential avenues for studying this eco-friendly TiO2 synthesis method for innovative implementations.
TL;DR: In this paper, high transparent thin films of aluminium doped ZnO along with specific silver co-doping are deposited by sol-gel spin coating, which show preferred single orientation along (100) plane.
Abstract: Highly transparent thin films of aluminium doped ZnO along with specific silver co-doping are deposited by sol-gel spin coating, which show preferred single orientation along (100) plane. Presence ...
TL;DR: In this article, a facile sol-gel type process involving composite amorphous precursor powders was used to obtain recrystallized CZO NPs from the precursors.
TL;DR: In this paper, the effects of MoO3 amount on the phase composition, microstructure, physical properties such as firing shrinkage, open porosity, bending strength, water absorption and bulk density of porous mullite ceramics were investigated.
TL;DR: In this paper, the incorporation of therapeutic elements in these materials, such as boron (B) and calcium (Ca), was considered as an approach to develop biomaterials capable of stimulating bone regeneration.
Abstract: Poly(dimethylsiloxane) (PDMS)-SiO2-CaO-based hybrid materials prepared by sol-gel have proved to be very promising materials for tissue engineering applications and drug-delivery systems. These hybrids are biocompatible and present osteogenic and bioactive properties supporting osteoblast attachment and bone growth. The incorporation of therapeutic elements in these materials, such as boron (B) and calcium (Ca), was considered in this study as an approach to develop biomaterials capable of stimulating bone regeneration. The main purpose of this work was thus to produce, by sol-gel, bioactive and biocompatible hybrid materials of the PDMS-SiO2-B2O3-CaO system, capable of a controlled Ca and B release. Different compositions with different boron amounts were prepared using the same precursors resulting in different monolithic materials, with distinct structures and microstructures. Structural features were assessed by Fourier transform infrared (FT-IR) spectrometry and solid-state nuclear magnetic resonance (NMR) techniques, which confirmed the presence of hybrid bonds (Si-O-Si) between organic (PDMS) and inorganic phase (tetraethyl orthosilicate (TEOS)), as well as borosiloxane bonds (B-O-Si). From the 11B NMR results, it was found that Ca changes the boron coordination, from trigonal (BO3) to tetrahedral (BO4). Scanning electron microscopy (SEM) micrographs and N2 isotherms showed that the incorporation of boron modifies the material's microstructure by increasing the macroporosity and decreasing the specific surface area (SSA). In vitro tests in simulated body fluid (SBF) showed the precipitation of a calcium phosphate layer on the material surface and the controlled release of therapeutic ions. The cytocompatibility of the prepared hybrids was studied with bone marrow stromal cells (ST-2 cell line) by analyzing the cell viability and cell density. The results demonstrated that increasing the dilution rate of extraction medium from the hybrids leads to improved cell behavior. The relationship between the in vitro response and the structural and microstructural features of the materials was explored. It was shown that the release of calcium and boron ions, determined by the hybrid structure was crucial for the observed cells behavior. Although not completely understood, the encouraging results obtained constitute an incentive for further studies on this topic.
TL;DR: In this paper, a low-cost sol-gel spin-coating technique is used for the simple synthesis of eco-friendly ZnO multilayer films deposited on (100)-oriented silicon substrates ranging from 150 to 600 nm.
Abstract: Zinc oxide (ZnO) is a II–VI group semiconductor with a wide direct bandgap and is an important material for various fields of industry and high-technological applications. The effects of thickness, annealing process in N2 and air, optical properties, and morphology of ZnO thin-films are studied. A low-cost sol–gel spin-coating technique is used in this study for the simple synthesis of eco-friendly ZnO multilayer films deposited on (100)-oriented silicon substrates ranging from 150 to 600 nm by adjusting the spin coating rate. The ZnO sol–gel thin-films using precursor solutions of molarity 0.75 M exhibit an average optical transparency above 98%, with an optical band gap energy of 3.42 eV. The c-axis (002) orientation of the ZnO thin-films annealed at 400 °C were mainly influenced by the thickness of the multilayer, which is of interest for piezoelectric applications. These results demonstrate that a low-temperature method can be used to produce an eco-friendly, cost-effective ZnO sol–gel that is compatible with a complementary metal-oxide-semiconductor (CMOS) and integrated-circuits (IC).
TL;DR: In this paper, a nanocrystalline TiO2 glass coating was developed by sintering sol-gel derived thin film at 450°C. FTIR spectroscopy confirmed the absence of hydroxide gel and unreacted precursor as well as the p...
Abstract: A nanocrystalline TiO2 glass coating was developed by sintering sol–gel derived thin film at 450°C. FTIR spectroscopy confirmed the absence of hydroxide gel and unreacted precursor as well as the p...
TL;DR: In this article, the thermochromism of m-BiVO4 films prepared by a modified citrate-route of simple sol-gel spin coating method, for the first time, is reported.