scholarly journals Structure and Properties of Mixed Former Aluminum Borate Glasses Modified With Silver Oxide

2021 ◽  
Author(s):  
Gomaa El-Damrawi ◽  
H Salah
Keyword(s):  
Activation Energy ◽  
Ionic Conduction ◽  
Material Structure ◽  
X Ray Diffraction ◽  
Molar Ratios ◽  
Hardness Number ◽  
Transmission Electron ◽  
Wide Range ◽  
Structured Groups ◽  
Substantial Change

Abstract The current study focuses on glass preparation and characterization in the xAl2O3 (35-x) Ag2O.65B2O3 system (0≤x≤35 mol%), where Ag2O is replaced with Al2O3. To examine a wide range of both structure and morphology of the produced glasses, nuclear magnetic resonance (NMR) of 27Al nuclei, X-ray diffraction (XRD) spectroscopy, and transmission electron microscopy (TEM) are used. Changing the Al2O3 and Ag2O molar ratios reveals a substantial change in material structure. In Al2O3-rich glass, the well-formed AlO6, AlO5, and AlO4 structured groups are the well-formed units. In samples of (20 and 30 mol % Al2O3), tetrahedral AlO4 and traces from AlO6 units may be detected. At lower concentrations of Al2O3 (10 mol%), the dominant unit is only AlO4 groups containing non-bridging oxygen bonds (NBO). The XRD and EDP spectra confirm the amorphous nature of the glasses of Al2O3 ˂ 20 mol%. Glasses of higher Al2O3 concentrations contain crystalline Ag2Al2B2O7 which are formed due to the higher oxygen packaging of the mixed AlO5 and AlO4 compared with that of glasses containing only AlO4 species. The amount of higher coordinated Al species AlO5 and AlO6 are gradually increased in response to an increase in the ratios of Al2O3/Ag2O. The morphology of crystalline units is confirmed from TEM to differ from that of an amorphous composition. The conductivity decreases and the activation energy for ionic conduction increase with increasing Al2O3. The hardness number of the studied glasses is highly increased with increasing Al2O3 content. The increase of activation energy and the hardness number of the glasses led to an increase in the durability of the investigated glasses.

scholarly journals Influence of Nitridation on Structural and Photoluminescence Behaviour of CaZrO3:Eu3+ Nanophosphors

2020 ◽  
Vol 32 (6) ◽  
pp. 1515-1519
Author(s):  
S.G. Prasanna Kumar ◽  
Nagaraju Kottam ◽  
R. Hari Krishna ◽  
M.N. Chandra Prabha ◽  
R. Preetham ◽  
...  
Keyword(s):  
Solution Combustion Synthesis ◽  
Orthorhombic Phase ◽  
X Ray Diffraction ◽  
Solution Combustion ◽  
Sem Images ◽  
Small Shift ◽  
Nitridation Time ◽  
Transmission Electron ◽  
Wide Range ◽  
Temperature Solution

Ca1-xZrO3:xEu3+ (x = 0.05) phosphors have been prepared by using the low temperature solution combustion synthesis. The prepared nano phospors are well characterized by powder X-ray diffraction, scanning electron microscopy, Fourier infrared spectroscopy and transmission electron spectroscopy. PXRD results showed orthorhombic phase and SEM images showed porous agglomerated morphology. Influence of nitridation on structural and photoluminescence properties of the phosphor were investigated for wide range of nitridation time. The photoluminescence (PL) intensity was found to vary with nitridation with small shift in the photoluminescence emission peaks. The probable reasons for the variation of photoluminescence with nitridation are discussed.

Synthesis and Ionic Conductivity of MAlSi3O8 (M = Li, Na, K)

2018 ◽  
Vol 790 ◽  
pp. 9-14
Author(s):  
Shin Ichi Furusawa ◽  
Yohei Minami
Keyword(s):  
Activation Energy ◽  
Ionic Conductivity ◽  
Ionic Radius ◽  
Ionic Conduction ◽  
Solid Phase ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
X Ray Diffraction ◽  
Crystalline Phases ◽  
X Ray

MAlSi3O8 (M = Li, Na, K) was synthesized by solid-phase reaction at 1000 °C using M2CO3 (M = Li, Na, K), Al2O3, and SiO2 as the starting materials, and its ionic conduction was studied in the temperature range 475–800 K. It was confirmed from powder X-ray diffraction profiles that the crystalline phases of the prepared MAlSi3O8 were the same as those of orthoclase. Moreover, the ionic conductivity of NaAlSi3O8 was about 10 times higher than that of LiAlSi3O8 and KAlSi3O8. The activation energies for ionic conduction were estimated to be in the range of 0.70–0.77 eV, with NaAlSi3O8 exhibiting the lowest activation energy. The result suggests that the magnitude of the activation energy cannot be determined only from the ionic radius.

scholarly journals Cypermethrin elimination using Fe-TiO2 nanoparticles supported on coconut palm spathe in a solar flat plate photoreactor

2020 ◽  
Vol 29 ◽  
pp. 2633366X2090616
Author(s):  
Ricardo Andrés Solano Pizarro ◽  
Adriana Patricia Herrera Barros
Keyword(s):  
Electron Microscopy ◽  
Flat Plate ◽  
Diffuse Reflectance Spectroscopy ◽  
Cocos Nucifera ◽  
Operating Costs ◽  
Bet Surface Area ◽  
Gas Chromatography Mass Spectrometry ◽  
X Ray Diffraction ◽  
Molar Ratios ◽  
Transmission Electron

In this research, the photocatalytic degradation of cypermethrin using iron-titanium dioxide (Fe-TiO2) nanoparticles supported in a biomaterial was evaluated. The nanoparticles of TiO2 were synthesized by the green chemistry method assisted by ultrasound and doped by chemical impregnation using Fe+3:Ti molar ratios of 0, 0.05, 0.075 and 0.1 to make efficient use of direct sunlight ( λ > 310 nm). All nanoparticles were immobilized on the surface of coconut spathe ( Cocos nucifera). The degradation was carried out at room temperature and natural pH in a flat plate solar reactor, on which the composite material was subjected. The concentration of cypermethrin was determined after 12,000 J m−2 of accumulated radiation from gas chromatography–mass spectrometry and the resulting material was characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, ultraviolet–visible diffuse reflectance spectroscopy, and Brunauer-Emmett-Teller (BET) surface area. The best results were achieved with the use of Evonik TiO2 P-25, Fe:Ti = 0 and Fe:Ti = 0.05 in suspension, with percentages of degradation of cypermethrin of 99.84%, 99.62%, and 100%, respectively. However, the materials supported on the biomaterial of coconut allowed to reach degradation percentages higher than 80%, with the advantage that it minimizes operating costs, as they are not necessarily filtering or centrifuging processes to separate the catalyst.

Preparation and Property of Al87Ce3Ni8.5Mn1.5 Nanophase Amorphous Composites

2011 ◽  
Vol 412 ◽  
pp. 263-266
Author(s):  
Hong Wei Zhang ◽  
Li Li Zhang ◽  
Feng Rui Zhai ◽  
Jia Jin Tian ◽  
Can Bang Zhang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Single Phase ◽  
Volume Fraction ◽  
Material Structure ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Transmission Electron ◽  
Different Temperatures

The higher mechanical strength of Al87Ce3Ni8.5Mn1.5 nanophase amorphous composites has been obtained with two methods. The first nanophase amorphous composites are directly produced by the single roller spin quenching technology. The method taken for the second nanophase amorphous composites is at first to obtain amorphous single-phase alloy, followed by annealed at different temperatures .The formative condition, the microstructure, the particle size, the volume fraction of α-Al phase and microhardness of nanophase amorphous composites etc have been investigated and compared by X-ray diffraction (XRD) and transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). The microstructure of composites produced by the second method is higher than the former, the fabricated material structure of the system is more uniform and the process is easier to control.

Synthesis of Fe2O3/CNTs for the Fast Removal of Tetracycline from Aqueous Solutions

2014 ◽  
Vol 915-916 ◽  
pp. 933-941 ◽  
Author(s):  
Zhong Jie Zhang ◽  
Chang Yu Lu ◽  
Wei Huang ◽  
Wei Sheng Guan ◽  
Yue Xin Peng
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Magnetic Measurements ◽  
Ferrite Nanoparticles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Wide Range ◽  
Fast Removal ◽  
Scanning Electron

The effective remove to tetracycline still remains a big challenge for scientists. In this work, we used a new method for preparing functional magnetic CNTS with ferrite nanoparticles. A wide range of techniques, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and magnetic measurements were applied to characterize the obtained Fe2O3/CNTs. Moreover, we have also studied the properties of adsorbent to tetracycline. In addition, we have found that the Fe2O3/CNTs are better reusable adsorbent than other traditional adsorbents by magnetic separation recycling method.

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.

Structural Characterization of Heteroepitaxial 3C-SiC

2012 ◽  
Vol 711 ◽  
pp. 27-30 ◽  
Author(s):  
Andrea Severino ◽  
Ruggero Anzalone ◽  
Massimo Camarda ◽  
Nicolò Piluso ◽  
Francesco La Via
Keyword(s):  
Growth Rate ◽  
Film Structure ◽  
Material Structure ◽  
X Ray Diffraction ◽  
Si Substrates ◽  
Transmission Electron ◽  
Crystallographic Defects ◽  
Sic Film ◽  
Sic Films

In this work, we focus our attention on the characterization of 3C-SiC films, grown within a CVD reactor, on Si substrates. It will be shown how the growth procedures influence the SiC film structure and quality with the growth rate used during the growth used as example. Evaluation of crystal structure has been conducted by X-Ray Diffraction (XRD), Raman microscopy and Transmission Electron Microscopy (TEM). Overall film quality increases if films are grown under low growth rate conditions, thanks also to an important reduction in the density of micro-twins. The trend of the full widths at half maximum (FWHMs) of SiC rocking curves, considered good ‘quality indicator’ as their broadenings are affected by crystallographic defects, as a function of 3C-SiC thickness shows a saturated regime for very thick films, due to the saturation of stacking fault density after 50 μm of growth. This work wants to suggest a reasonable path for the characterization of the material structure that can be useful, anywhere and in any time, to assess if the morphology and microstructure of our films are satisfactory and to drive towards the desired improvement.

scholarly journals Liquid petroleum gas sensing performance enhanced by CuO modification of nanocrystalline ZnO-TiO2

2016 ◽  
Vol 34 (3) ◽  
pp. 571-581
Author(s):  
R.B. Pedhekar ◽  
F.C. Raghuwanshi ◽  
V.D. Kapse
Keyword(s):  
Thick Film ◽  
Gas Sensing ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Molar Ratios ◽  
Transmission Electron ◽  
Liquid Petroleum Gas ◽  
Synthesized Materials ◽  
Sensing Characteristics

AbstractNanocrystalline ZnO-TiO2 (with molar ratios 9:1, 7:3, 1:1, 3:7 and 1:9) were successfully synthesized by hydrothermal method. Synthesized materials were examined with the help of X-ray diffraction and transmission electron microscope. Liquid petroleum gas sensing characteristics of the ZnO-TiO2 films were investigated at different operating temperatures. The ZnO-TiO2 thick film (with 1:1 molar ratio) exhibited good response toward liquid petroleum gas as compared to other investigated compositions. Further, liquid petroleum gas sensing characteristics of CuO modified ZnO-TiO2 thick films were investigated. 0.2 M CuO modified ZnO-TiO2 thick film exhibited excellent liquid petroleum gas sensing characteristics such as higher response (~ 1637.49 at 185 °C) with quick response time (~30 s), low recovery time (~70 s), excellent repeatability and stability at low operating temperature.

Effect of nanomaterials in platinum-decorated carbon nanotube paste-based electrodes for amperometric glucose detection

2008 ◽  
Vol 23 (5) ◽  
pp. 1457-1465 ◽  
Author(s):  
Jining Xie ◽  
Shouyan Wang ◽  
L. Aryasomayajula ◽  
V.K. Varadan
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Electrochemical Impedance ◽  
Glucose Sensing ◽  
Electrochemical Characteristics ◽  
Current Response ◽  
X Ray Diffraction ◽  
Multiwalled Carbon ◽  
Transmission Electron ◽  
Wide Range

The effect of nanomaterials in platinum-decorated, multiwalled, carbon nanotube-based electrodes for amperometric glucose sensing was investigated by a comparative study with other carbon material-based electrodes such as graphite, glassy carbon, and multiwalled carbon nanotubes. Scanning and transmission electron microscopy and x-ray diffraction were used to investigate their morphologies and crystallinities. Electrochemical impedance spectroscopy was conducted to compare the electrochemical characteristics of these electrodes. The glucose-sensing results from the chronoamperometric measurements indicated that carbon nanotubes improve the linearity of the current response to glucose concentrations over a wide range, and that platinum decoration of the carbon nanotubes produces improved electrochemical performance with a higher sensitivity.

scholarly journals Формирование кремниевых нанокластеров при диспропорционировании моноокиси кремния

2021 ◽  
Vol 55 (4) ◽  
pp. 373
Author(s):  
Д.А. Ложкина ◽  
Е.В. Астрова ◽  
Р.В. Соколов ◽  
Д.А. Кириленко ◽  
А.А. Левин ◽  
...  
Keyword(s):  
Activation Energy ◽  
Solid Phase ◽  
Silicon Monoxide ◽  
Nanocrystalline Silicon ◽  
X Ray Diffraction ◽  
Isochronous Annealing ◽  
Transmission Electron ◽  
Amorphous Medium ◽  
The Difference ◽  
First Time

In this work, the processes of disproportionation of solid-phase silicon monoxide, accompanied by the formation of nanocrystalline silicon precipitates in the medium of amorphous SiOx suboxide (initial composition SiO0.9), have been studied. Based on the data of X-ray diffraction analysis and transmission electron microscopy, the dynamics of changes in the amount, concentration and size of phase precipitates of silicon with an increase in the temperature of isochronous annealing from 800 °C to 1200 °C is traced. It was found that with a monotonic increase in the total mass of the precipitated silicon, the number of its crystallization centers per unit volume nonmonotonically depends on temperature. The activation energy of diffusion of silicon atoms in the SiOx matrix was determined to be Ea1= 1.64 eV, and the activation energy of their transfer from the formed precipitates to the growth medium of SiOx was Ea2 = 2.38 eV. Anisotropic deformation of silicon crystallites precipitated during the disproportionation of SiO has been revealed for the first time. This phenomenon is associated with the difference in the specific volumes of the separated phases and the anisotropy of the growth rate of silicon precipitates formed in a solid amorphous medium.

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