scholarly journals Synthesis of NiFe2O4 nanofibers by joint sol-gel and electrospinning technique

10.30544/387 ◽  
2018 ◽  
Vol 24 (3) ◽  
pp. 173-180
Author(s):  
Aleksandar Grujić ◽  
Vladan Ćosović ◽  
Jasna Stajić-Trošić ◽  
Aleksandar Ćosović ◽  
Mirko Stijepović ◽  
...  
Keyword(s):  
Elevated Temperatures ◽  
Sol Gel ◽  
Morphological Characteristics ◽  
Magnetic Behavior ◽  
Composition Analysis ◽  
X Ray Diffraction ◽  
Electrospinning Technique ◽  
Web Structure ◽  
Crystallite Sizes ◽  
Ft Ir

In this study, electrospinning combined with sol-gel technique is applied in order to produce magnetic nickel ferrite (Ni-ferrite) nanofibers. The prepared Ni-ferrite gel was mixed with poly(vinylpyrrolidone) (PVP) solution which was used as a spinning aid to enable spinnability of the mixture. Structural and morphological characteristics of the as-spun ferrite gel/PVP composite web structure and calcinated Ni-ferrite nanofibers were analyzed using scanning electron microscopy (SEM). Phase composition analysis was carried out by Fourier-transform infrared (FT-IR) spectroscopy, X-Ray diffraction analysis (XRD) and 57Fe Mössbauer spectroscopy (MS). The obtained results suggest that the pure nanocrystalline NiFe2O4 dense mat to the almost coral-like structure of fibers with diameters ranging from hundreds of nanometers to few micrometers was obtained. The results of MS analysis revealed the existence of a crystallite size distribution within the material as well as the existence of a superparamagnetic fraction with very small crystallite sizes (<13nm). Magnetic behavior of the obtained material at elevated temperatures was also scrutinized using thermomagnetic measurements (TM) up to 800 °C.

scholarly journals Effect of Silica Embedding on the Structure, Morphology and Magnetic Behavior of (Zn0.6Mn0.4Fe2O4)δ/(SiO2)(100−δ) Nanoparticles

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2232
Author(s):  
Thomas Dippong ◽  
Iosif Grigore Deac ◽  
Oana Cadar ◽  
Erika Andrea Levei
Keyword(s):  
Crystallite Size ◽  
Sol Gel ◽  
Magnetic Behavior ◽  
Average Crystallite Size ◽  
Chemical Transformations ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Structure Morphology ◽  
Crystallite Sizes ◽  
Ft Ir

The effect of SiO2 embedding on the obtaining of single-phase ferrites, as well as on the structure, morphology and magnetic properties of (Zn0.6Mn0.4Fe2O4)δ(SiO2)100−δ (δ = 0–100%) nanoparticles (NPs) synthesized by sol-gel method was assessed. The phase composition and crystallite size were investigated by X-ray diffraction (XRD), the chemical transformations were monitored by Fourier transform infrared (FT-IR) spectroscopy, while the morphology of the NPs by transmission electron microscopy (TEM). The average crystallite size was 5.3–27.0 nm at 400 °C, 13.7–31.1 nm at 700 °C and 33.4–49.1 nm at 1100 °C. The evolution of the saturation magnetization, coercivity and magnetic anisotropy as a function of the crystallite sizes were studied by vibrating sample magnetometry (VSM) technique. As expected, the SiO2 matrix shows diamagnetic behavior accompanied by the accidentally contribution of a small percent of ferromagnetic impurities. The Zn0.6Mn0.4Fe2O4 embedded in SiO2 exhibits superparamagnetic-like behavior, whereas the unembedded Zn0.6Mn0.4Fe2O4 behaves like a high-quality ferrimagnet. The preparation route has a significant effect on the particle sizes, which strongly influences the magnetic behavior of the NPs.

Structural and Photoluminescence Characteristics of ZnTiO3:Pb2+ Nanofibers Produced by Electrospinning

2013 ◽  
Vol 562-565 ◽  
pp. 908-913 ◽  
Author(s):  
Rong Li Sang ◽  
Ying Chen ◽  
Qing Jun Zhang ◽  
Lin Wang
Keyword(s):  
Sol Gel ◽  
Excitation Wavelength ◽  
X Ray Diffraction ◽  
Electrospinning Technique ◽  
X Ray ◽  
Charge Transfer Transitions ◽  
Ultrathin Fibers ◽  
Ft Ir ◽  
Gel Processing ◽  
Scanning Electron

By sol-gel processing and electrospinning technique, ultrathin fibers of PVP/ ZnTiO3:Pb2+ composites were synthesized. After calcined of the fibers at 600°C, the spinel ZnTiO3:Pb2+ nanofibers, with a diameter of 100-200nm, were successfully obtained. The scanning electron microscopy (SEM), fourier transform infrared (FT-IR), X-ray diffraction (XRD) and photoluminescence (PL) were employed in the study. The results displayed that the morphology and crystalline phase of the fibers were greatly affecteded by the calcination temperature. The PL spectra of the samples measured at different excitation wavelength reveal a novel luminescent phenomenon in blue and green region, which can be attributed to the Pb2+-related charge-transfer transitions in ZnTiO3 nanofibers.

scholarly journals Synthesis and characterization of magnetic recyclable Fe-substituted zinc aluminate photocatalysts with enhanced sunlight-driven degradation of industrial dyes

2020 ◽  
Author(s):  
Thanit Tangcharoen ◽  
Jiraroj T-Thienprasert ◽  
Chanapa Kongmark
Keyword(s):  
Organic Dyes ◽  
Magnetic Measurements ◽  
Sol Gel ◽  
Magnetic Behavior ◽  
Bandgap Energy ◽  
Magnetic Photocatalyst ◽  
Auto Combustion ◽  
Crystallite Sizes ◽  
Phase Spinel ◽  
Ft Ir

Abstract Using the sol-gel auto combustion approach with diethanolamine (DEA) as fuel, a sequence of iron-substituted zinc aluminates, ZnFexAl2−xO4 powders, including variable Fe3+ ion concentrations (0 ≤ x ≤ 2) were effectively created. XRD, FT-IR, SEM, EDS, BET, UV-DRS, and VSM were employed to examine the structures, chemical bonds, morphologies, composition, surface area, and optical properties as well as the magnetic behavior of the collected samples. A single-phase spinel structure was gained for the calcined aluminate powders with different interplanar spacing and crystallite sizes, as revealed by the classification results. The bandgap energy (Eg) of adapted aluminates was in the range of 2.08–3.14 eV, identified as being much lower compared to the pure sample (5.60 eV). Thus, Fe3+-substituted ZnAl2O4 samples could be successfully photoexcited using both ultraviolet and visible light, as suggested by the results. Examination of how the four main pollutant types decay when irradiated by sunlight was carried out to assess the samples and establish photocatalytic activity. These contaminants included phenol rhodamine B (RhB), heteropolyaromatic methylene blue (MB), azoic methyl orange (MO) and methyl red (MR). The performance of photocatalytic degradation reached 98% after 150 minutes for all optimal samples of organic dyes. Besides, each of the altered photocatalysts could be recycled and displayed high stability. The S-shaped curve of ferrimagnetism can result from in those samples as found by the magnetic measurements, though pure ZnAl2O4 displays diamagnetic characteristics. The adapted samples show intense improvement in the remanent magnetization (Mr) when compared to pure ZnAl2O4, signifying that magnetic photocatalyst recovery by applying an external magnetic field is easy. Thus, these results offer a convincing sign that ZnAl2O4 powders replaced by Fe3+ could provide the ability to aid in the ecologically-friendly collection of solar energy.

scholarly journals Structural and magnetic studies on Co-Zn nanoferrite synthesized via sol-gel and combustion methods

2019 ◽  
Vol 37 (1) ◽  
pp. 39-54 ◽  
Author(s):  
B.B.V.S. Vara Prasad ◽  
K.V. Ramesh ◽  
A. Srinivas
Keyword(s):  
Citric Acid ◽  
Chelating Agents ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Gel Method ◽  
X Ray ◽  
Sol Gel Method ◽  
Three Samples ◽  
Crystallite Sizes ◽  
Ft Ir

AbstractCo–Zn nanocrystalline ferrites with chemical composition Co0:5Zn0:5Fe2O4 were synthesized by sol-gel and combustion methods. The sol-gel method was carried out in two ways, i.e. based on chelating agents PVA and PEG of high and low molecular weights. In auto-combustion method, the ratio of citric acid to metal nitrate was taken as 1:1, while in sol-gel method the chelating agents were taken based on oxygen balance. All the three samples were studied by thermogravimetric and differential thermal analysis for the identification of phase formation and ferritization temperature. The synthesized samples were characterized by powder X-ray diffraction and FT-IR spectroscopy without any thermal treatment. The measured lattice constants and observed characteristic IR absorption bands of the three samples are in good agreement with the reported values showing the formation of a cubic spinel structure. The crystallite sizes of all samples were determined using high intensity peaks and W-H plot. Size-Strain Plot method was also implemented since two of the samples showed low crystallite sizes. The least crystallite size (5.5 nm) was observed for the sample CZVP while the highest (23.8 nm) was observed for the sample CZCA. Cation distribution was proposed based on calculated and observed intensity ratios of selected planes from X ray diffraction data. All structural parameters were presented using experimental lattice constant and oxygen positional parameter, and they correlated with FT-IR results. Magnetic measurements were carried out using vibrating sample magnetometer at room temperature to obtain the characteristic parameters such as saturation magnetization, coercivity, remanence, squareness ratio and Bohr magnetons. Among all, the sample synthesized via citric acid autocombustion method displayed a remarkably higher magnetization of 53 emu/g and the remaining two samples displayed low magnetization values owing to their smaller crystallite sizes.

Fabrication of ZnTiO3 Nanofibers by Electrospinning

2013 ◽  
Vol 562-565 ◽  
pp. 57-61
Author(s):  
Rong Li Sang ◽  
Jun Shao ◽  
Lin Wang
Keyword(s):  
Electron Microscopy ◽  
Chemical Sensors ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Electrospinning Technique ◽  
X Ray ◽  
Ultrathin Fibers ◽  
Ft Ir ◽  
Gel Processing ◽  
Scanning Electron

Ultrathin fibers of PVP/ZnTiO3 composite were prepared through sol-gel processing and electrospinning technique. After calcined of the above precursor fibers at 600°C, the spinel ZnTiO3 nanofibers, with a diameter of 50-150nm, were successfully obtained. The fibers were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and fourier transform infrared (FT-IR), respectively. The results displayeded that the morphology and crystalline phase of the fibers were largely influenced by the calcination temperature. The reported strategy will be useful for fabricating one-by-one continuous nanofibers, which are suitable for applications in catalysis, chemical sensors, nanoelectrodes, and nanodevices.

scholarly journals Synthesis and characterization of nanocrystalline barium strontium titanate powder by a modified sol-gel processing

2016 ◽  
Vol 34 (1) ◽  
pp. 63-68 ◽  
Author(s):  
M.E. Azim Araghi ◽  
N. Shaban ◽  
M. Bahar
Keyword(s):  
Sol Gel ◽  
Research Work ◽  
Titanium Isopropoxide ◽  
Barium Acetate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sol Gel Process ◽  
Crystallite Sizes ◽  
Ft Ir ◽  
Strontium Acetate

AbstractIn this research work, nanocrystalline BST (Ba0.6Sr0.4TiO3) powders were synthesized through a modified sol-gel process, using barium acetate, strontium acetate and titanium isopropoxide as the precursors. In this process, stoichiometric proportions of barium acetate and strontium acetate were dissolved in acetic acid and titanium (IV) isopropoxide was added to form BST gel. The as-formed gel was dried at 200 °C and then calcined in the temperature range of 600 to 850 °C for crystallization. The samples were characterized by infrared spectroscopy method (FT-IR), X-ray diffraction technique (XRD) and field emission scanning electron microscope (FESEM) and energy dispersive X-ray spectroscopy. EDS analysis of these samples confirmed the formation of the final phase with the special stoichiometry. The formation of a cubic perovskite crystalline phase with nanoscale dimension was detected using the mentioned techniques. The results showed that the obtained crystallite sizes were 33 and 37 nm for BST powder calcined at 750 and 850 °C, respectively.

Luminescent Properties of Zn2SiO4:Eu3+,Dy3+ Phosphors via Sol-Gel Process

2012 ◽  
Vol 217-219 ◽  
pp. 733-736
Author(s):  
Xiu Mei Han ◽  
Shu Ai Hao ◽  
Ying Ling Wang ◽  
Gui Fang Sun ◽  
Xi Wei Qi
Keyword(s):  
Thermal Analysis ◽  
Ir Spectra ◽  
Sol Gel ◽  
Luminescent Properties ◽  
Photoluminescence Spectra ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sol Gel Process ◽  
Ft Ir

Zn2SiO4:Eu3+, Dy3+ phosphors have been prepared through the sol-gel process. X-ray diffraction (XRD), thermogravimetric and ddifferential thermal analysis (TG-DTA), FT-IR spectra and photoluminescence spectra were used to characterize the resulting phosphors. The results of XRD indicated that the phosphors crystallized completely at 1000oC. In Zn2SiO4:Eu3+,Dy3+ phosphors, the Eu3+ and Dy3+ show their characteristic red(613nm, 5D0-7F2), blue (481nm, 4F9/2–6H15/2) and yellow (577nm, 4F9/2–6H13/2) emissions.

Characterization of SrBi2Nb2O9 Thin Films Prepared by Sol Gel Technique

1996 ◽  
Vol 459 ◽  
Author(s):  
E. Ching-Prado ◽  
W. Pérez ◽  
A. Reynés-Figueroa ◽  
R. S. Katiyar ◽  
D. Ravichandran ◽  
...  
Keyword(s):  
Thin Films ◽  
Raman Band ◽  
Sol Gel ◽  
Orthorhombic Symmetry ◽  
X Ray Diffraction ◽  
Ft Ir ◽  
Gel Technique ◽  
High Degree ◽  
First Time

ABSTRACTThin films of SrBi2Nb2O9 (SBN) with thicknesses of 0.1, 0.2, and 0.4 μ were grown by Sol-gel technique on silicon, and annealed at 650°C. The SBN films were investigated by Raman scatering for the first time. Raman spectra in some of the samples present bands around 60, 167, 196, 222, 302, 451, 560, 771, 837, and 863 cm−1, which correspond to the SBN formation. The study indicates that the films are inhomogeneous, and only in samples with thicknesses 0.4 μ the SBN material was found in some places. The prominent Raman band around 870 cm−1, which is the A1g mode of the orthorhombic symmetry, is assigned to the symmetric stretching of the NbO6 octahedrals. The frequency of this band is found to shift in different places in the same sample, as well as from sample to sample. The frequency shifts and the width of the Raman bands are discussed in term of ions in non-equilibrium positions. FT-IR spectra reveal a sharp peak at 1260 cm−1, and two broad bands around 995 and 772 cm−1. The bandwidths of the latter two bands are believed to be associated with the presence of a high degree of defects in the films. The experimental results of the SBN films are compared with those obtained in SBT (T=Ta) films. X-ray diffraction and SEM techniques are also used for the structural characterization.

Effect of Synthesis Temperature on Particles Size and Morphology of Zirconium Oxide Nanoparticle

2017 ◽  
Vol 50 ◽  
pp. 18-31 ◽  
Author(s):  
Rudzani Sigwadi ◽  
Simon Dhlamini ◽  
Touhami Mokrani ◽  
Patrick Nonjola
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Zirconium Oxide ◽  
Thermo Gravimetric Analysis ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Crystallite Sizes ◽  
Ft Ir

The paper presents the synthesis and investigation of zirconium oxide (ZrO2) nanoparticles that were synthesised by precipitation method with the effects of the temperatures of reaction on the particles size, morphology, crystallite sizes and stability at high temperature. The reaction temperature effect on the particle size, morphology, crystallite sizes and stabilized a higher temperature (tetragonal and cubic) phases was studied. Thermal decomposition, band structure and functional groups were analyzed by Brunauer-Emmett-Teller (BET), Scanning Electron Microscopy (SEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD), Thermo-gravimetric analysis (TGA) and Fourier transform infrared (FT-IR). The crystal structure was determined using X-ray diffraction. The morphology and the particle size were studied using (SEM) and (TEM). The shaped particles were confirmed through the SEM analysis. The transmission electron microscopic analysis confirmed the formation of the nanoparticles with the particle size. The FT-IR spectra showed the strong presence of ZrO2 nanoparticles.

Preparation and Photocatalytic Properties of Rod-Shaped TiO2 Based on Salix Fiber

2014 ◽  
Vol 609-610 ◽  
pp. 250-254
Author(s):  
Ya Bin Li ◽  
Jin Tian Huang ◽  
Yan Fei Pan
Keyword(s):  
Photocatalytic Performance ◽  
Sol Gel ◽  
Average Diameter ◽  
X Ray Diffraction ◽  
Nanocomposite Structure ◽  
X Ray ◽  
Infrared Spectrometer ◽  
Ft Ir ◽  
Degradation Of Methyl Orange ◽  
Scanning Electron

In the paper, the TiO2nanomaterials adopted the microcrystalline cellulose as the template by the template method and sol-gel method was prepared. Through the infrared spectrometer (FT-IR), scanning electron microscope (SEM), X-ray diffraction (XRD), the surface morphology, composition and the type of the samples were characterized respectively. The influence of the macro morphology of TiO2photocatalytic performance to use the reaction of decolorization and degradation of methyl orange as model was analyzed. The results showed that TiO2which was produced by the template of sallix fiber was Rod-shaped and the average diameter size of nanocomposite structure was 20.592 nm, which can provide a new method of producing other morphology of TiO2.

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