STUDY ON SYNTHESIS AND EVOLUTION OF NANOCRYSTALLINE Mg4Ta2O9 BY AQUEOUS SOL–GEL PROCESS

2012 ◽  
Vol 19 (03) ◽  
pp. 1250024 ◽  
Author(s):  
H. T. WU ◽  
C. H. YANG ◽  
W. B. WU ◽  
Y. L. YUE
Keyword(s):  
Electron Microscopy ◽  
Solid State ◽  
Sol Gel ◽  
Phase Evolution ◽  
Solid State Method ◽  
Conventional Solid State Method ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
State Method ◽  
Size And Morphology

Nanosized and highly reactive Mg4Ta2O9 were successfully synthesized by aqueous sol–gel method compared with conventional solid-state method. Ta-Mg-citric acid solution was first formed and then evaporated resulting in a dry gel for calcination in the temperature ranging from 600°C to 800°C for crystallization in oxygen atmosphere. The crystallization process from the gel to crystalline Mg4Ta2O9 was identified by thermal analysis and phase evolution of powders was studied using X-ray diffraction (XRD) technique during calcinations. Particle size and morphology were examined by transmission electron microscopy (TEM) and high resolution scanning electron microscopy (HR-SEM). The results revealed that sol–gel process showed great advantages over conventional solid-state method and Mg4Ta2O9 nanopowders with the size of 20–30 nm were obtained at 800°C.

scholarly journals A Study and Comparison of the Preparation of Gadolinium Aluminate Nanoparticles Using γ-Irradiated and Unirradiated Precursors

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Tehani I. Al-Muhimeed ◽  
Abdullah A. Al-Kahtani ◽  
Refaat M. Mahfouz ◽  
Mujeeb Khan ◽  
M. Rafiq H. Siddiqui
Keyword(s):  
Electron Microscopy ◽  
Solid State ◽  
Sol Gel ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
Sintered Pellet ◽  
X Ray Diffraction ◽  
Gadolinium Nitrate ◽  
Transmission Electron ◽  
Sol Gel Process

The effects of γ-irradiation and the application of different precursors on the formation of gadolinium aluminate (GdAlO3) nanoparticles (NPs) have been studied in detail. GdAlO3 NPs were prepared by using different gadolinium-based precursors including gadolinium acetate (Gd(CH3COO)3·4H2O) and gadolinium nitrate (Gd(NO3)3·6H2O), while Al2O3 and Al(NO3)3·9H2O were used as the source of Al3+. The preparation of GdAlO3 was carried out by two different methods, solid-state reaction and sol-gel process. To study the effect of γ-irradiation, both irradiated and unirradiated Gd(CH3COO)3·4H2O have been tested for the preparation of gadolinium aluminate (GdAlO3). Notably, Gd(CH3COO)3·4H2O did not produce GdAlO3 in both solid-state and sol-gel processes even after optimizing various parameters, including the application of γ-irradiation. However, single-phase nanocrystalline GdAlO3 NPs were successfully obtained from the reaction of gadolinium nitrate Gd(NO3)3·6H2O and Al(NO3)3·9H2O by a sol-gel process. The formation of NPs has been confirmed by X-ray diffraction analysis (XRD) and Fourier-transform infrared (FT-IR) spectroscopy. The results indicate towards the formation of an orthorhombic perovskite structure of GdAO3 in the Pbnm space group. Transmission electron microscopy (TEM) has been employed for the particle-size analysis, which revealed the formation of spherical-shaped nanoparticles with the size range of 50–70 nm. Surface morphology of the sintered pellet was obtained from high-resolution scanning electron microscopy (HR-SEM). Besides, the effect of irradiation with γ-rays on the quality of resultant NPs has also been studied.

scholarly journals Synthesis, structure and magnetic properties of (Eu1−xMnx)MnO3−δ

RSC Advances ◽  
2017 ◽  
Vol 7 (4) ◽  
pp. 2019-2024 ◽  
Author(s):  
Jianming Deng ◽  
Aimei Yang ◽  
M. A. Farid ◽  
Hao Zhang ◽  
Jian Li ◽  
...  
Keyword(s):  
Solid Solution ◽  
Magnetic Properties ◽  
Solid State ◽  
Solid State Method ◽  
Conventional Solid State Method ◽  
State Method

The solid solution (Eu1−xMnx)MnO3−δ (0 ≤ x ≤ 0.126) has been synthesized using a conventional solid-state method.

Characterization and optical limiting behavior of BaSnO3 powder prepared by the conventional solid state method

2020 ◽  
Vol 29 ◽  
pp. 1091-1097
Author(s):  
Jibi John ◽  
S.R. Chalana ◽  
V.P. Mahadevan Pillai ◽  
Jaison Joseph ◽  
S. Muthunatesan ◽  
...  
Keyword(s):  
Solid State ◽  
Optical Limiting ◽  
Solid State Method ◽  
Limiting Behavior ◽  
Conventional Solid State Method ◽  
State Method

Characterization of Nanostructured Silica as Carrier for Insecticides Deltamethrin, Pyriproxyfen, and Chlorpyrifos and Testing the Insecticidal Efficacy Against Trogoderma granarium (Coleoptera: Dermestidae) Larvae

2019 ◽  
Vol 113 (1) ◽  
pp. 511-517
Author(s):  
Masumeh Ziaee ◽  
Asgar Babamir-Satehi
Keyword(s):  
Electron Microscopy ◽  
Silica Nanoparticles ◽  
Sol Gel ◽  
Sem Analysis ◽  
Efficient Treatment ◽  
Trogoderma Granarium ◽  
Transmission Electron ◽  
Insecticidal Efficacy ◽  
Sol Gel Process ◽  
Nanostructured Silica

Abstract Nanostructured silica can be used as a carrier of pesticides to enhance stability and controlled release of agrochemicals with an effective concentration on target pests. Silica nanoparticles (SNPs) were synthesized by sol–gel process and employed as a carrier of three different insecticides including deltamethrin, pyriproxyfen, and chlorpyrifos. The SNPs were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis and the insecticides-loaded in SNPs were characterized by transmission electron microscopy (TEM). The toxicity of insecticides alone and loaded in SNPs was evaluated against small and large larvae of Trogoderma granarium Everts on concrete surfaces. The immediate mortality was counted after 1, 3, and 7 d of exposure, and then surviving individuals were transferred to untreated surfaces for seven more days, with delayed mortality was recorded. Small larvae were more susceptible than large ones on all insecticide treatments. In addition, insecticides loaded in silica nanoparticles were more effective when compared with application of the insecticides alone. For immediate mortality, deltamethrin loaded in SNPs was the most efficient treatment causing 70.5% mortality on small and 55.5% mortality on large larvae after 7 d of exposure to the highest concentration. Pyriproxyfen loaded in SNPs caused low immediate mortality, but the mortality increased in delayed count indicated that the insecticide could control the larvae even after they have been removed from treated surfaces. It can be concluded that loading insecticides in SNPs could significantly increase their insecticidal efficiency, but this increase was compound-dependent.

Synthesis and Characterization of SiO2@Y2MoO6:Eu3+ Core–Shell Structured Spherical Phosphors by Sol–Gel Process

2016 ◽  
Vol 16 (4) ◽  
pp. 3914-3920 ◽  
Author(s):  
G. Z Li ◽  
F. H Liu ◽  
Z. S Chu ◽  
D. M Wu ◽  
L. B Yang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Annealing Temperature ◽  
Uv Light ◽  
Sol Gel ◽  
Spherical Shape ◽  
Core Shell ◽  
X Ray ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Average Size

SiO2@Y2MoO6:Eu3+ core–shell phosphors were prepared by the sol–gel process. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectra (EDS), transmission electron microscopy (TEM), photoluminescence (PL) spectra as well as kinetic decays were used to characterize the resulting SiO2@Y2MoO6:Eu3+ core–shell phosphors. The XRD results demonstrated that the Y2MoO6:Eu3+ layers on the SiO2 spheres crystallized after being annealed at 700 °C and the crystallinity increased with raising the annealing temperature. The obtained core–shell phosphors have spherical shape with narrow size distribution (average size ca. 640 nm), non-agglomeration, and smooth surface. The thickness of the Y2MoO6:Eu3+ shells on the SiO2 cores could be easily tailored by varying the number of deposition cycles (70 nm for four deposition cycles). The Eu3+ shows a strong PL emission (dominated by 5D0–7F2 red emission at 614 nm) under the excitation of 347 nm UV light. The PL intensity of Eu3+ increases with increasing the annealing temperature and the number of coating cycles.

scholarly journals Fabrication of TiO2Nanotanks Embedded in a Nanoporous Alumina Template

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
C. Massard ◽  
S. Pairis ◽  
V. Raspal ◽  
Y. Sibaud ◽  
K. O. Awitor
Keyword(s):  
Electron Microscopy ◽  
Sol Gel ◽  
Thermal Treatments ◽  
X Ray Diffraction ◽  
Alumina Template ◽  
Nanoporous Alumina ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Sol Gel Process

The feasibility of surface nanopatterning with TiO2nanotanks embedded in a nanoporous alumina template was investigated. Self-assembled anodized aluminium oxide (AAO) template, in conjunction with sol gel process, was used to fabricate this nanocomposite object. Through hydrolysis and condensation of the titanium alkoxide, an inorganic TiO2gel was moulded within the nanopore cavities of the alumina template. The nanocomposite object underwent two thermal treatments to stabilize and crystallize the TiO2. The morphology of the nanocomposite object was characterized by Field Emission Scanning Electron Microscopy (FESEM). The TiO2nanotanks obtained have cylindrical shapes and are approximately 69 nm in diameter with a tank-to-tank distance of 26 nm. X-ray diffraction analyses performed by Transmission Electron Microscopy (TEM) with selected area electron diffraction (SAED) were used to investigate the TiO2structure. The optical properties were studied using UV-Vis spectroscopy.

Microstructural characteristics and photoluminescence performance of nanograined thermally treated CeO2-TiO2 xerogels

2007 ◽  
Vol 22 (5) ◽  
pp. 1182-1187
Author(s):  
Amita Verma ◽  
A.K. Srivastava ◽  
N. Karar ◽  
Harish Chander ◽  
S.A. Agnihotry
Keyword(s):  
Electron Microscopy ◽  
Crystallite Size ◽  
Sol Gel ◽  
Structural Features ◽  
X Ray Diffraction ◽  
Molar Ratios ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Crystallite Sizes ◽  
Thermally Treated

Nanostructured thermally treated xerogels have been synthesized using a sol-gel process involving cerium (Ce) chloride heptahydrate and titanium (Ti) propoxide mixed in different Ce:Ti molar ratios. Structural features of the xerogels have been correlated with their photoluminescence (PL) response. The crystallite sizes in the samples lie in the nanorange. The x-ray diffraction and transmission electron microscopy results have confirmed the coexistence of CeO2 and TiO2 nanocrystallites in these xerogels. In general, a decrease in the CeO2 crystallite size and an increase in the TiO2 crystallite size are observed in the xerogels as a function of Ti content. Scanning electron microscopy results have evidenced the evolution of ordered structure in the xerogels as a function of TiO2 content. Although both of the phases (CeO2 and TiO2) have exhibited PL in ultraviolet and visible regions, the major luminescence contribution has been made by the CeO2 phase. The largest sized CeO2 crystallites in 1:1 thermally treated xerogel have led to its highest PL response. PL emission in the xerogels is assigned to their nanocrystalline nature and oxygen vacancy-related defects.

Effects of Compounding Addition of Sintering Aids on DC Bias Superposition Characteristic of NiCuZn Ferrites

2013 ◽  
Vol 668 ◽  
pp. 21-24
Author(s):  
Li Dong ◽  
Ze Kun Feng ◽  
Shuo Qing Yan
Keyword(s):  
Grain Size ◽  
Solid State ◽  
Significant Relationship ◽  
Sintering Aids ◽  
Solid State Method ◽  
Conventional Solid State Method ◽  
Dc Bias ◽  
State Method

NiCuZn ferrites were prepared through conventional solid-state method. The effects of the sintering aids such as Bi2O3 and glass on the DC bias superposition characteristic of NiCuZn Ferrites were investigated. It was apparently discovered that when the glass and the Bi2O3 were doped together, the grain size was distributed consistently and the DC bias superposition characteristic reached an achievement comparing to the situation when the Bi2O3 and glass were doped alone. Additionally, it was also observed that the DC bias superposition characteristic had a significant relationship with Hc and △B.

TEM Study of Rutile-Phase TiO2 Nanosheets

2013 ◽  
Vol 850-851 ◽  
pp. 156-159
Author(s):  
Xin Yan Wu ◽  
Wei Xiong
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Photocatalytic Activity ◽  
Energy Dispersive Spectrometer ◽  
Sol Gel ◽  
Rutile Phase ◽  
High Photocatalytic Activity ◽  
X Ray ◽  
Transmission Electron ◽  
Sol Gel Process

TiO2 nanosheets have been successfully synthesized via a simple sol-gel process. These nanostructures were characterized by transmission electron microscopy (TEM) and x-ray energy dispersive spectrometer (EDS). The sheet-shaped single-crystalline nanostructures are pure rutile-phase structure, with landscape dimension of 10-45 nm. EDS investigation confirms that the TiO2 nanosheets are only composed of Ti and O, and the atomic ration of Ti and O is close to 1:2. High photocatalytic activity might be expected for those TiO2 nanosheets due to their large surface area.

scholarly journals Structural, optical and dielectric properties of tellurium-based double perovskite Sr2Ni1−xZnxTeO6

RSC Advances ◽  
2021 ◽  
Vol 11 (50) ◽  
pp. 31631-31640
Author(s):  
Fatasya Izreen Hanim Alias ◽  
Rozilah Rajmi ◽  
Mohd Fauzi Maulud ◽  
Zakiah Mohamed
Keyword(s):  
Dielectric Properties ◽  
Solid State ◽  
Double Perovskite ◽  
Solid State Method ◽  
Conventional Solid State Method ◽  
State Method

In this paper, Sr2Ni1−xZnxTeO6 (x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) double perovskite compounds were synthesised by the conventional solid-state method, and the structural, optical and dielectric properties were investigated.

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