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.

Effect of Flux Boric Acid (H3BO3) on Yttrium Silicate Y2SiO5:Dy3+ (9 mol%) Nanophosphors Its Characterization and Luminescence Studies

2019 ◽  
Vol 17 (11) ◽  
pp. 898-904
Author(s):  
K. Dhanalakshmi ◽  
A. Jagannatha Reddy
Keyword(s):  
Boric Acid ◽  
Solution Combustion Synthesis ◽  
Particle Morphology ◽  
X Ray Diffraction ◽  
Solution Combustion ◽  
X Ray ◽  
Yttrium Silicate ◽  
Auto Ignition ◽  
Dosimetric Peak ◽  
Temperature Solution

Flux Boric acid (H3BO3) doped on Y2SiO5:Dy3+ phosphors were synthesized by auto ignition based low temperature Solution Combustion Synthesis (SCS) using Oxalic acid dihydrate (ODH) as fuel. Powder X-ray diffraction (PXRD) patterns confirm the nano sized particles corresponding to JCPDS card 36-1476. The crystallite size of the samples estimated from Scherer's formula and Williamson-Hall (W-H) plots was found to be in the range ˜21 nm and 26 nm respectively. Scanning electron Microscope (SEM) micrographs infer addition of flux gives the enhanced grain growth and it attains smooth surface improves the crystallinity and particle morphology of the sample. Fourier transform Infrared (FTIR) data reveals the presence of M–O bonds and Y–O bonds and also the bands at 642 cm–1, 655 cm–1, 668 cm–1, 697 cm–1, 719 cm–1 are ascribed due to the B–O–B linkage in the borate network. Addition of flux on Thermoluminescence (TL) glow curves from 0.5 KGy–4 KGy acts as a sensitizer and the peak appearing at 185 °C is quite stable and can be named as "dosimetric peak" to use in TL phosphor. The kinetic parameters estimated by Chen's peak shape method was found to be second order with activation energy 0.82.

scholarly journals Fabrication of La2O3 Uniformly Doped Mo Nanopowders by Solution Combustion Synthesis Followed by Reduction under Hydrogen

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2385 ◽  
Author(s):  
Siyong Gu ◽  
Mingli Qin ◽  
Houan Zhang ◽  
Jidong Ma
Keyword(s):  
Combustion Synthesis ◽  
Hydrogen Reduction ◽  
Synthesis Method ◽  
Reduction Process ◽  
Solution Combustion Synthesis ◽  
Particle Sizes ◽  
X Ray Diffraction ◽  
Solution Combustion ◽  
X Ray ◽  
Transmission Electron

This work reports the preparation of La2O3 uniformly doped Mo nanopowders with the particle sizes of 40–70 nm by solution combustion synthesis and subsequent hydrogen reduction (SCSHR). To reach this aim, the foam-like MoO2 precursors (20–40 nm in size) with different amounts of La2O3 were first synthesized by a solution combustion synthesis method. Next, these precursors were used to prepare La2O3 doped Mo nanopowders through hydrogen reduction. Thus, the content of La2O3 used for doping can be accurately controlled via the SCSHR route to obtain the desired loading degree. The successful doping of La2O3 into Mo nanopowders with uniform distribution were proved by X-ray photon spectroscopy and transmission electron microscopy. The preservation of the original morphology and size of the MoO2 precursor by the La2O3 doped Mo nanopowders was attributed to the pseudomorphic transport mechanism occurring at 600 °C. As shown by X-ray diffraction, the formation of Mo2C impurity, which usually occurs in the direct H2 reduction process, can be avoided by using the Ar calcination-H2 reduction process, when residual carbon is removed by the carbothermal reaction during Ar calcination at 500 °C.

Structure and Luminescence of Ce-doped Lu2SiO5 Nanophosphor

2007 ◽  
Vol 1056 ◽  
Author(s):  
Michael Wayne Blair ◽  
Luiz G Jacobsohn ◽  
Bryan L Bennett ◽  
Ross E Muenchausen ◽  
Stephanie C Sitarz ◽  
...  
Keyword(s):  
Stokes Shift ◽  
Emission Spectra ◽  
Solution Combustion Synthesis ◽  
Luminescent Properties ◽  
X Ray Diffraction ◽  
Solution Combustion ◽  
Paramagnetic Resonance ◽  
Transmission Electron ◽  
Electron Energy Loss ◽  
Ce Content

ABSTRACTNanophosphors correspond to nanostructured inorganic insulator materials that emit light under particle or electromagnetic radiation excitation. In this work we investigate the structure and luminescent properties of Ce-doped Lu2SiO5 (LSO) nanophosphors prepared by solution combustion synthesis with the Ce content 0.1 to 12 at. %. Samples were characterized by transmission electron microscopy (TEM), line scan electron energy-loss spectroscopy (EELS), x-ray diffraction (XRD), and electron paramagnetic resonance (EPR) spectroscopy. Photoluminescence excitation and emission spectra are composed of two major bands centered at 360 and 430 nm, respectively. These results reveal a red-shift and enhanced Stokes shift for the nanophosphors when compared to bulk. Ce content was also found to affect photoluminescence emission intensity and fluorescent lifetime. The nanophosphor concentration quenching curve presents a broad maximum centered at 1 at.%. Lifetime measurements show a continuous decrease from 34 to 21 ns as Ce content is increased.

Flameless Solution Combustion Synthesis of Al3+ Doped LiMn2O4

2011 ◽  
Vol 186 ◽  
pp. 7-10 ◽  
Author(s):  
Gui Yang Liu ◽  
Jun Ming Guo ◽  
Bao Sen Wang ◽  
Ying He
Keyword(s):  
Combustion Synthesis ◽  
Synthesis Method ◽  
Solution Combustion Synthesis ◽  
Xrd Analysis ◽  
Cycling Performance ◽  
X Ray Diffraction ◽  
Solution Combustion ◽  
Electrochemical Test ◽  
Micro Morphology ◽  
Better Than

Single phase Al3+ doped LiMn2O4 has been prepared by flameless solution combustion synthesis method at 600oC for 1h. X-ray diffraction (XRD) and scanning electric microscope (SEM) were used to determine the phase composition and micro morphology of the products. XRD analysis indicates that the purities increase and the lattice parameters of the products decrease with increasing Al3+ content. Electrochemical test indicates that the cycling performance of the products with Al3+ doping are better than that of the product without Al3+ doping. The product LiAl0.10Mn1.90O4 gets the best electrochemical performance. At the current density of 30mA/g, the initial discharge capacity of LiAl0.10Mn1.90O4 is 124.8mAh/g, and after 20 cycles, the capacity retention is more than 89%. SEM investigation indicates that the particles of LiAl0.10Mn1.90O4 are sub-micron in size and well dispersed.

Fabrication and Microstructure of Ge-Sb-S-CsCl Chalcogenide Glass Containing β-GeS2 Nanocrystals

2014 ◽  
Vol 665 ◽  
pp. 119-123
Author(s):  
Ji Yan Hao ◽  
Hai Tao Liu
Keyword(s):  
Chalcogenide Glass ◽  
Spherical Shape ◽  
Orthorhombic Phase ◽  
Far Infrared ◽  
X Ray Diffraction ◽  
Base Glass ◽  
X Ray ◽  
Transmission Electron ◽  
Infrared Spectral ◽  
Quenching Method

we report the fabrication and microstructure of Ge-Sb-S-CsCl chalcogenide glass containing β-GeS2 nanocrystals. A Ge-Sb-S-CsCl chalcogenide base glass with the better crystalline ability is first fabricated by melt-quenching method, and a further careful thermal process has led to the formation of β-GeS2 nanocrystals in the glass. Transmission electron microscopy showed that the size of β-GeS2 nanocrystals with nearly monodisperse spherical shape ranges from 30 to 45 nm in the glass. Powder X-ray diffraction results confirm that the β-GeS2 nanocrystals are of high crystallization with orthorhombic phase. Energy dispersive spectroscopy is employed for the information of nanocrystals glass composition. It is worthwhile to note that the obtained Ge-Sb-S-CsCl chalcogenide glass containing β-GeS2 nanocrystals still keeps higher transmittance in mid- and far- infrared spectral region.

scholarly journals Oxide-Clay Mineral as Photoactive Material for Dye Discoloration

Minerals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 132
Author(s):  
Maicon O. Miranda ◽  
Bartolomeu Cruz Viana ◽  
Luzia Maria Honório ◽  
Pollyana Trigueiro ◽  
Maria Gardênnia Fonseca ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Clay Mineral ◽  
Uv Light ◽  
High Photocatalytic Activity ◽  
X Ray Diffraction ◽  
Sem Images ◽  
Zirconium Oxides ◽  
Transmission Electron ◽  
Palygorskite Clay

Titanium and zirconium oxides (TiO2 and ZrO2, respectively) were obtained from alkoxides hydrolyses, and then deposited into palygorskite clay mineral (Pal) to obtain new materials for photocatalytic applications. The obtained materials were characterized by structural, morphological, and textural techniques. X-ray diffraction (XRD) results confirmed the characteristic peaks of oxides and clay transmission electron microscopy (TEM) and scanning electron microscopy (SEM) images of the modified palygorskite with both oxides showed that the clay was successfully modified by the proposed method. The increase in the specific surface area of the clay occurred when TiO2 and ZrO2 were deposited on the surface. The photocatalytic activity of these materials was investigated using the Remazol Blue anion dye under UV light. The evaluated systems presented high photocatalytic activity, reaching approximately 98% of dye discoloration under light. Thus, TiO2–Pal and ZrO2–TiO2–Pal are promising clay mineral-based photocatalysts.

scholarly journals Study of Green and Chemical Methods for Synthesis of Nano Spinel MgFe2O4 and its Study on Degradation of Rose Bengal Dye

2020 ◽  
Vol 32 (3) ◽  
pp. 501-507
Author(s):  
Krushitha Shetty ◽  
B.S. Prathibha ◽  
Dinesh Rangappa ◽  
K.S. Anantharaju ◽  
H.P. Nagaswarupa ◽  
...  
Keyword(s):  
Combustion Synthesis ◽  
Rose Bengal ◽  
Sol Gel ◽  
Solution Combustion Synthesis ◽  
X Ray Diffraction ◽  
Solution Combustion ◽  
Chemical Methods ◽  
Transfer Resistance ◽  
X Ray ◽  
Rose Bengal Dye

MgFe2O4 nanoferrites were synthesized by sol-gel and solution combustion synthesis (SCS) methods through green and chemical methods. Green and chemical methods for sol-gel were processed with use of lemon extract and citric acid, respectively. A green and chemical method for solution combustion synthesis was followed by using Phyllanthus acidus leaf extract and urea, respectively. The influence of synthesis approach on the behaviour of prepared nanoferrites were studied using powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and UV visible spectroscopy, vast variation in particle size, crystallinity, electrochemical and photocatalytic activity of the nanoferrites synthesized by various methods were witnessed. Powder X-ray diffraction (PXRD) result of prepared nanoferrites acquired by green and chemical approaches clarified phase structure as spinel and the crystalline size found to be around 11-24 nm. The spinel surface morphology was witnessed for the synthesized nanoferrites. The tetrahedral and octahedral sites of the prepared nanoferrites were confirmed by FTIR spectra. MgFe2O4 nanoferrites synthesized by green sol-gel approach exposed superior electrochemical activity by possessing very less charge transfer resistance. The results of EIS were correlated with the photocatalytic degradation of Rose Bengal dye. Photocatalytic property of the prepared nanoferrites was examined for photodegradation of Rose Bengal dye under UV-light.

Microwave-Assisted Solution Combustion Synthesis and Characterization of Thermoelectric Ca3Co2O6 Powders

2013 ◽  
Vol 802 ◽  
pp. 84-88
Author(s):  
Sagulthai Kahatta ◽  
Nopsiri Chaiyo ◽  
Chesta Ruttanapun ◽  
Wicharn Techitdheera ◽  
Wisanu Pecharapa ◽  
...  
Keyword(s):  
Combustion Synthesis ◽  
Solution Combustion Synthesis ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Solution Combustion ◽  
X Ray ◽  
Microwave Assisted ◽  
Product Characterization ◽  
Rhombohedral Crystal Structure ◽  
Rhombohedral Crystal

The microwave-assisted solution combustion synthesis was applied to the initial synthesizing of Ca3Co2O6powder using glycine as a fuel and nitrate as an oxidant. The as-synthesized powders were calcined at 700-1,000ºC for 4h. Product characterization was performed using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and Scanning electron microscope (SEM). The fuel-to-oxidizer molar ratio was found to affect the combustion reaction and character of the powder obtained. The phase composition of powder after calcination at various temperatures has shown that the formation of Ca3Co2O6occurs directly. The calcined powder possesses a rhombohedral crystal structure with an X-ray diffraction pattern that could be matched with the Ca3Co2O6JCPDS: 89-0629. This method is a simple way of synthesizing fine Ca3Co2O6powder with a low calcination temperature.

Shape control of silver selenide nanoparticles using green capping molecules

2017 ◽  
Vol 6 (2) ◽  
Author(s):  
Nokwethemba Precious Sibiya ◽  
Makwena Justice Moloto
Keyword(s):  
Shape Control ◽  
Orthorhombic Phase ◽  
Silver Selenide ◽  
Capping Agent ◽  
X Ray Diffraction ◽  
Synthesis Of Nanoparticles ◽  
Size And Shape ◽  
Transmission Electron ◽  
Different Shapes ◽  
Average Size

AbstractEmploying a capping agent during the synthesis of nanoparticles has been reported to play a role in controlling size and shape of the nanoparticles. Due to this reason, this study reports the synthesis of silver selenide nanoparticles using different environmentally friendly capping agents (green tea, glucose, ascorbic acid and chitosan) in order to investigate their effect on the size and shape of the nanoparticles. Transmission electron microscopy (TEM) results showed that the nanoparticles have different shapes (rods, spheres and cubes) with an average size of 8–96 nm depending on the capping agent used. Fourier transformer infrared (FTIR) spectroscopy confirmed that the capping of nanoparticles was successful, while X-ray diffraction (XRD) showed that the nanoparticles have an orthorhombic phase.

Temperature Dependence of LiMn2O4 Prepared by a Solution Combustion Synthesis in the System of Acetate Salts and Acetic Acid

2012 ◽  
Vol 485 ◽  
pp. 465-468
Author(s):  
Li Li Zhang ◽  
Gui Yang Liu ◽  
Jun Ming Guo ◽  
Bao Sen Wang ◽  
Ying He
Keyword(s):  
Acetic Acid ◽  
Combustion Synthesis ◽  
Raw Materials ◽  
Synthesis Method ◽  
Solution Combustion Synthesis ◽  
Electrochemical Performances ◽  
Metal Foil ◽  
X Ray Diffraction ◽  
Solution Combustion ◽  
Acid Ratio

Spinel LiMn2O4 have been prepared by the solution combustion synthesis method using acetate salts as raw materials and acetic acid as fuel. The phase compositions of the as-prepared products were determined by X-ray diffraction (XRD). The electrochemical performance of the products was tested by using a coin-type half battery versus lithium metal foil as anode material. XRD results suggested that the purities of the products prepared at 500oC are higher than these of the products prepared at 600oC. For the products prepared at 500oC, the purities of the products increase with increasing acetic acid ratios. But for the products prepared at 600oC, the purities of the products decrease with increasing acetic acid ratios. The performance tests indicated that the electrochemical performances of the products prepared at 500oC are better than these of the products prepared at 600oC. The product prepared at 500oC with the acetic acid ratio of 1.0 gets the best performance. The initial capacity of it reaches to 124.8mAh/g at the current density of 75mA/g, and after 50 cycles, the capacity retention is 93.7%.

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