scholarly journals Effect of Preheating Temperature on Synthesis of Pure BiFeO3 via Sol–Gel Method

Nanopages ◽  
2019 ◽  
pp. 1-11
Author(s):  
G. M. Taha ◽  
M. N. Rashed ◽  
M. S. El-Sadek ◽  
M. A. Moghazy

Abstract BiFeO3 (BFO) nanopowder was synthesized in a pure form via a sol- gel method based on glycol gel reaction. Effect of drying and preheating temperature on preventing other phases was studied. Many parameters were studied as calcination temperature and time & stirring temperature as well. The prepared powder was characterized by X-Ray Diffraction of powder (XRD) and Transmission Electron Microscope (TEM). High pure BiFeO3 was obtained by preheated process at 400 °C for 0.5 h and calcination at 600 °C for 0.5 h without any impurities compared to dry at110 °C.

2016 ◽  
Vol 680 ◽  
pp. 189-192
Author(s):  
Zhao Jun Liu ◽  
Kang Ning Sun ◽  
Ai Min Li ◽  
Xiao Ning Sun ◽  
Shu Pin Zhang

In this study, LiZn ferrites with different content of CNTs (1%-9%) were successfully prepared by a sol-gel method. X-ray diffraction pattern exhibit a relatively high crystallinity of the Li0.25Zn0.5Fe2.25O4/CNTs composite, and the CNTs still exist after acid treatment and subsequent heat treatment. Then the composite was characterized by scanning electron microscope (SEM) and transmission electron microscope (TEM), the results demonstrate that the particles are nearly spherical in shape and agglomerated to some extent. By a sol-gel method and subsequent calcination, the temperature of LiZn ferrites/CNTs temperature control biomaterials gradually increase and maintain at a certain temperature in the alternating magnetic field, so it can be a potential material used for hyperthermia applications.


2014 ◽  
Vol 609-610 ◽  
pp. 281-287
Author(s):  
Ying Chen ◽  
Peng Liu ◽  
Zhi Wu Yu

Tetraethyl orthosilicate (TEOS), butyl titanate [Ti (OBu)4] and aluminium isopropoxide were used as molecular precursor of ternary nanoSiO2-Al2O3-TiO2 materials. The influences of temperature and the dosage of compounds on the characteristic of ternary nanomaterials were investigated. Transmission electron microscopy (TEM), x-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) were employed to investigate the characteristics of the nanomaterials synthesized by the sol-gel method. In addition, the adsorption of nanomaterials for different kinds of surfactants was also studied. Results revealed that the influences of temperature, compounds dosages and water on the size of ternary nanomaterials had a significant impact. With the increase of ammonia dosage, the concentration of the OH- ion became higer, and system showed a faster reaction rate. The higer temperature of the system was, the larger size of the ternary nanomaterials was. Moreover, the higer tempreature woule also lead to divide into layer and precipitate. Optimal parameters can be chosen to prepare monodispersed ternary nanoSiO2-Al2O3-TiO2 materials. Results also showed that the surface characteristic of ternary nanoSiO2-Al2O3-TiO2 particles differed from nanosilica, which manifested in forms of the adsorption dosage of surfactants.


2016 ◽  
Vol 254 ◽  
pp. 200-206 ◽  
Author(s):  
Catalina Nuțescu Duduman ◽  
María Isabel Barrena Pérez ◽  
José Maria Gómez de Salazar ◽  
Ioan Carcea ◽  
Daniela Lucia Chicet ◽  
...  

Nanostructured SnO2 was prepared based on the sol-gel method used in the preparation of crystalline metal oxides. Sol-gel process can be described as a forming network of oxide polycondensation reaction of a molecular precursor in a liquid. Six experiments were carried out. Morphological structures and chemical composition were examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) after calcination. It is noted that TEM images show that the spheres consist from nanocrystals, quantitative EDS analysis of the chemical composition shows an absence of the chlorine, which is a desired fact. For structural characterization of the material we used X-Ray Diffraction (XRD). The X-ray diffraction pattern for all samples indicates peaks which are agreeable with standard diffraction pattern of SnO2. The particle size of all samples was in the range of 28-92 nm calculated according to Scherrer equation.


2018 ◽  
Vol 8 ◽  
pp. 184798041880064 ◽  
Author(s):  
VM Maphiri ◽  
BF Dejene ◽  
TE Motaung ◽  
TT Hlatshwayo ◽  
OM Ndwandwe ◽  
...  

Mg1.5Al2O4.5: x% Eu3+ (0 ≤ x ≤ 2) nanopowders were successfully synthesized via sol–gel method. The X-ray diffraction (XRD) spectrum revealed that the Mg1.5Al2O4.5: x% Eu3+ matches the single phase of face-centred cubic MgAl2O4. The estimated average crystallite sizes calculated using the XRD spectra were found to be in the order of 4 nm. The estimated crystal size was confirmed by the high-resolution transmission electron microscopy. The energy dispersive X-ray spectroscopy confirmed the presence of all expected elementary composition (Mg, Al, O and Eu). The field emission gun scanning electron microscope showed that varying the Eu3+ concentration influence the morphology of the prepared nanophosphor. The photoluminescence results showed that the host emits the violet colour at around 382 nm, which was attributed to the defects within the band gap ( Eg) of host material. The Eu3+-doped samples showed the emission at around 560, 580, 593, 618, 655 and 704 nm which are, respectively, attributed to the 5D1 → 7F3, 5D0 → 7F0, 5D0 → 7F1, 5D0 → 7F2, 5D0 → 7F3 and 5D0 → 7F4 characteristic transitions in Eu3+. The International Commission on Illumination colour chromaticity showed that the Eu3+ doping influences the emission colour.


2012 ◽  
Vol 599 ◽  
pp. 104-107
Author(s):  
Fang Zhao ◽  
Ya Qiong Zhao ◽  
Yuan Yuan Li ◽  
Gang Ni

This study investigated the effect of cationic, anionic, and nonionic surfactants on the formation, morphology, and surface properties of TiO2 nanoparticles synthesized by modified sol-gel method. The crystalline structures and morphologies of the powder have been characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The XRD results showed TiO2 nanoparticles synthesized with different surfactants only include anatase phase. The TEM analysis revealed the surfactants can enhance dispersion of TiO2 nanoparticles. In contrast, the anionic surfactants showed hightly effects. The photocatalytic activity of samples was tested for degradation of methyl orange (MO) solutions. The results showed photocatalytic activity of the catalyst with surfactants was higher than pure TiO2 under ultraviolet.


2007 ◽  
Vol 336-338 ◽  
pp. 2275-2277 ◽  
Author(s):  
Yan Xiang Peng ◽  
Min Qiang Wang

Transparent bulk CdSe/SiO2 nanocomposites, containing semiconductor CdSe nanocrystals well dispersed in silica glass matrix, were obtained by using sol-gel method and in-situ growth technique. The nanocomposites were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-VIS absorption spectra and X-ray Photoelectron Spectroscopy (XPS). X-ray diffraction and transmission electron microscope measurements confirmed a cubic crystallographic structure of the nanoparticles, with mean diameter smaller than 10 nm. UV-VIS absorption spectra displayed a marked blue shift of the absorption band edge that was attributed to quantum confinement effects. XPS together with XRD proved that silica matrix plays an important role in enhancing the NCs’ stability.


2021 ◽  
Author(s):  
Yan Chen ◽  
Yuemei Lan ◽  
Dong Wang ◽  
Guoxing Zhang ◽  
Wenlong Peng ◽  
...  

A series of Gd2-xMoO6:xEu3+(x=0.18-0.38) nanophosphors were synthesized by the solvothermal method. The properties of this nanophosphor were characterized by x-ray diffraction (XRD), transmission electron microscope (TEM), fluorescence spectra and diffuse...


2021 ◽  
Vol 3 (7) ◽  
Author(s):  
Alexandre Pancotti ◽  
Dener Pereira Santos ◽  
Dielly Oliveira Morais ◽  
Mauro Vinícius de Barros Souza ◽  
Débora R. Lima ◽  
...  

AbstractIn this study, we report the synthesis and characterization of NiFe2O4 and CoFe2O4 nanoparticles (NPs) which are widely used in the biomedical area. There is still limited knowledge how the properties of these materials are influenced by different chemical routes. In this work, we investigated the effect of heat treatment over cytotoxicity of cobalt and niquel ferrites NPs synthesized by sol-gel method. Then the samples were studied using transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometer (VSM), Fourier Transform Infrared Spectroscopy Analysis (FTIR), and X-ray fluorescence (XRF). The average crystallite sizes of the particles were found to be in the range of 20–35 nm. The hemocompatibility (erythrocytes and leukocytes) was checked. Cytotoxicity results were similar to those of the control test sample, therefore suggesting hemocompatibility of the tested materials.


2011 ◽  
Vol 80-81 ◽  
pp. 217-220 ◽  
Author(s):  
Xue Qing Yue ◽  
Hai Jun Fu ◽  
Da Jun Li

Graphite encapsulated nickel nanoparticles were prepared by ball milling andsubsequently annealing a mixture of expanded graphite with nickel powders. The products were characterized by transmission electron microscope and X-ray diffraction. The formation mechanism of the products was discussed. Results show that the products have a size range of 20-150 nm. The graphite and nickel in the products all exhibit a high crystallinity.


2012 ◽  
Vol 545 ◽  
pp. 275-278 ◽  
Author(s):  
Lili Widarti Zainuddin ◽  
Norlida Kamarulzaman

A ceramics sample of LiTaO3 was prepared using a sol-gel method. The sample is annealed at 750 °C for 48 hours. X-ray diffraction analysis indicate the formation of single phase, rhombohedral structure. An ac impedance study was used to analyse the conductivity of LiTaO3 at room temperature and at various temperatures.


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