Effect of pH on synthesis, characterization and fluorescence behavior of WO3:Eu3 nano powders

2021 ◽  
Vol 11 (10) ◽  
pp. 1716-1722
Author(s):  
Pengfei Wei ◽  
Dong Liang ◽  
Chunxiu Hu ◽  
Xiaojuan Zhang ◽  
Yuanfeng Ye ◽  
...  
Keyword(s):  
Average Particle Size ◽  
Electron Transition ◽  
Emission Peak ◽  
Average Particle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure And Morphology ◽  
Ph Values ◽  
Main Emission Peak ◽  
Fluorescence Spectrometer

WO3:Eu3+ nanoparticles with different pH values were prepared by citric acid method. The structure and morphology of nano-powders were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The luminescence properties of the nano-powders were tested by a fluorescence spectrometer. The results showed that the average particle size of the prepared WO3:Eu3+ nano powders were the smallest and reached 32 nm at pH = 1. Under different excitation wavelengths, the main emission peak of the sample was at 615 nm, corresponding to the 5D0 →7F2 electron transition of Eu3+. The emission intensity of WO3:Eu3+ nanoparticles prepared at pH = 5 was the highest at 615 nm.

One-Pot Synthesis of Environmental Friendly Ni3S2 Quantum Dots

2015 ◽  
Vol 1118 ◽  
pp. 9-13
Author(s):  
Yuan Kun Wang ◽  
Gui Liang Wu ◽  
Zhong Tao Li ◽  
Ming Bo Wu
Keyword(s):  
Quantum Dots ◽  
Average Particle Size ◽  
Fluorescence Emission ◽  
Emission Peak ◽  
Average Particle ◽  
X Ray Diffraction ◽  
One Pot ◽  
X Ray ◽  
Transmission Electron ◽  
Ultraviolet Light Irradiation

A one-pot synthetic method for non-toxic Ni3S2 quantum dots (QDs) was proposed by using commercial available nickel acetate as the precursor. The obtained quantum dots were characterized by photoluminescence spectroscopic, powder X-ray diffraction, and transmission electron microscopy. The maximum fluorescence emission peak of Ni3N2 QDs is at 469 nm under the 365 nm ultraviolet light irradiation in PL Spectra. The TEM data reveals that the predominance of particles with a polyhedron structure and the range of average particle size are between 5 and 11 nm.

scholarly journals Thermal, Structural, and Physical Properties of Freeze Dried Tropical Fruit Powder

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
K. A. Athmaselvi ◽  
C. Kumar ◽  
M. Balasubramanian ◽  
Ishita Roy
Keyword(s):  
Particle Size ◽  
Physical Properties ◽  
Average Particle Size ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Tropical Fruit ◽  
X Ray ◽  
Freeze Dried ◽  
Fruit Powder ◽  
Lcr Meter

This study evaluates the physical properties of freeze dried tropical (guava, sapota, and papaya) fruit powders. Thermal stability and weight loss were evaluated using TGA-DSC and IR, which showed pectin as the main solid constituent. LCR meter measured electrical conductivity, dielectric constant, and dielectric loss factor. Functional groups assessed by FTIR showed presence of chlorides, and O–H and N–H bonds in guava, chloride and C–H bond in papaya, and chlorides, and C=O and C–H bonds in sapota. Particle size and type of starch were evaluated by X-ray diffraction and microstructure through scanning electronic microscopy. A semicrystalline profile and average particle size of the fruit powders were evidenced by X-ray diffraction and lamellar/spherical morphologies by SEM. Presence of A-type starch was observed in all three fruits. Dependence of electric and dielectric properties on frequency and temperature was observed.

Preparation and Magnetic Properties of Carbon Encapsulated Fe-Cu Alloy Nanoparticles

2010 ◽  
Vol 177 ◽  
pp. 673-676 ◽  
Author(s):  
Jun Xue ◽  
Hou Kui Xiang ◽  
Hong Qiao Ding ◽  
Shu Li Pang ◽  
Xue Hua Wang ◽  
...  
Keyword(s):  
Magnetic Measurement ◽  
Average Particle Size ◽  
Soft Magnetic Property ◽  
Copper Nitrate ◽  
Synthesis Process ◽  
Ferric Nitrate ◽  
Average Particle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cu Alloy

Carbon encapsulated Fe-Cu alloys nanoparticles were synthesized by using ferric nitrate, copper nitrate as metal sources and using sucrose as carbon source. The synthesis process involved a step of hydrazine hydrate reduction in alcohol solution and a step of annealing carbonization. The as-prepared samples were characterized by X-ray diffraction technique, X-ray energy dispersion spectrograph, trans- mission electron microscopy and Raman spectroscopy. The results showed the sample was core / shell structure, the metalic core was crystalline FeCu4 alloy, the shell was amorphous carbon, and the average particle size was about 51nm. The magnetic measurement by using a vibrating sample magnetometer revealed that the sample has ultra-soft magnetic property with the saturation magnetization Ms of 13.01 emu/g, residual magnetization Mr of 0.37 emu/g and coercive forces Hc of 54.43 Oe at room temperature.

Preparation and Luminescence Properties of Sr2CeO4 Doped with Ho3+

2013 ◽  
Vol 591 ◽  
pp. 272-276
Author(s):  
Fang Zhang ◽  
Chao Song ◽  
Ling Li Ma ◽  
Xiao Li Xu ◽  
Zi Fei Peng
Keyword(s):  
Sintering Temperature ◽  
Average Particle Size ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Solid State Method ◽  
X Ray ◽  
Ultraviolet Excitation ◽  
Near Ultraviolet ◽  
State Method ◽  
Photo Luminescent

Sr2CeO4: Ho3+ was prepared by high-temperature solid-state method. The products were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and photo luminescent (PL). The Sr2CeO4:Ho3+ phosphors showed a red emission under the near-ultraviolet excitation (280 nm) and the main emission centered at 475 nm. It has been found that A+ (A+ = Li+, Na+ or K+) codoped Sr2CeO4: Ho3+ phosphors could lead to a remarkable increase of photoluminescence. Luminous intensity was the highest when doping Li+ ions. Investigation indicated that Sr2Ce0.989O4: 0.001Ho3+, 0.01Li+ exhibited the strongest emission. The average particle size was about 6 um. The optimum sintering temperature was 1200 °C and the possible mechanism was also discussed.

scholarly journals Structural Analysis of Platinum Nanoparticles on Carbon Nanotube Surface as Electrocatalyst System

2017 ◽  
Vol 9 (2) ◽  
pp. 60 ◽  
Author(s):  
Sudirman Sudirman ◽  
Indriyati Indriyati ◽  
Wisnu Ari Adi ◽  
Rike Yudianti ◽  
Emil Budianto
Keyword(s):  
Cell Volume ◽  
Unit Cell Volume ◽  
Average Particle Size ◽  
Unit Cell ◽  
Lattice Parameters ◽  
Atomic Density ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Great Opportunity ◽  
X Ray

Synthesis of Pt/CNT composite by using sol gel method has been performed which the composition of CNT on the composite are vary, (x = 20, 40, 60 and 80 wt%). Performance of composite was characterized by Transmission Electron Microscope (TEM) and X-Ray Diffraction (XRD), respectively. In the refinement results of X-ray diffraction pattern, the composite consists of two phases, namely, carbon and platinum phases. Carbon phase has a structure hexagonal (P 63 m c) with lattice parameters a = b = 2.451(2) Å and c = 6.89(1) Å, α = β = 90° and γ = 120°, the unit cell volume of V = 35.8(1) A3, and the atomic density of ρ = 2.224 g.cm-3. While platinum phase has the structure of cubic (F m -3 m) with lattice parameters a = b = c = 3.921(2) Å, α = β = γ = 90°, the unit cell volume of V = 60.3(1) A3, and the atomic density of ρ = 21.487 g.cm-3.According to the image of TEM, the average particle size for Pt nano particle is estimated to range from 4.1-4.3 nm. While the cavity diameter average of CNT is estimated to range from 5.9-7.5 nm. Based on the calculation, the crystallite size of the Pt particle was around 4.31 nm. The optimum value of dispersed Pt into CNT occurred at 60 wt% CNT with the best composition of Pt in the unit cell of cystal structure. We concluded that this study successfully dispersed Pt nanoparticles onto CNT formed Pt/CNT composite. This was a great opportunity that the composite can be applied as electrocatalyst system on fuel cell application.

DIELECTRIC PROPERTIES OF ULTRAFINE Zn-DOPED CaCu3Ti4O12 CERAMIC

2012 ◽  
Vol 02 (01) ◽  
pp. 1250007 ◽  
Author(s):  
LAXMAN SINGH ◽  
U. S. RAI ◽  
K. D. MANDAL ◽  
MADHU YASHPAL
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Room Temperature ◽  
Single Phase ◽  
Average Particle Size ◽  
Average Particle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Sintered Powder

Ultrafine powder of CaCu2.80Zn0.20Ti4O12 ceramic was prepared using a novel semi-wet method. DTA/TG analysis of dry powder gives pre-information about formation of final product around 800°C. The formation of single phase was confirmed by X-ray diffraction analysis. The average particle size of sintered powder of the ceramic obtained from XRD and Transmission electron microscopy was found 59 nm and 102 nm, respectively. Energy Dispersive X-ray studies confirm the stoichiometry of the synthesized ceramic. Dielectric constant of the ceramic was found to be 2617 at room temperature at 1 kHz.

Effect of Concentration of Iron Oxide on Crystallization Behavior in Leadless Iron Oxide Crystalline Glaze

2012 ◽  
Vol 554-556 ◽  
pp. 18-22
Author(s):  
Supakorn Silakate ◽  
Anucha Wannagon ◽  
Apinon Nuntiya
Keyword(s):  
Iron Oxide ◽  
Nepheline Syenite ◽  
Crystallization Behavior ◽  
Raw Materials ◽  
Average Particle Size ◽  
Average Particle ◽  
Oxide Content ◽  
Iron Oxide Content ◽  
X Ray Diffraction ◽  
X Ray

The objectives of this study were to prepare leadless crystalline glazes from iron oxide by using low temperature firing (1,100°C) and to study the effect of concentration of iron oxide on the phase composition of the glaze raw materials on phase transformation in leadless iron oxide crystalline glaze. The crystalline phases were investigated by using the DTA, X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The composition of the glaze raw materials compose of nepheline syenite, colemanite, pottery stone, bentonite, ZnO, Li2CO3, SiOSubscript text2 and 10, 15 and 20%(w/w) iron oxide (Fe2O3). The glaze raw materials were ground for homogeneous mixtures by ball milling for 24h. The average particle size of the mixture was 3.86 µm. The glaze bodies were carried to firing at 1,100°C at the heating rate of 2°C/min and soaking for 0.5h. Then, the glaze bodies were cooled at the cooling rate of 1°C/min and maintained at 1,080°C for 3h and then maintained at 980°C for 1h, respectively. From the experiment results, it was found that the crystallization temperatures (Tc) of franklinite (ZnFe2O4) and anorthite (CaAl2Si2O8) depend on the concentration of iron oxide content.

scholarly journals Biosintesis Nanopartikel Perak Menggunakan Ekstrak Metanol Daun Kemangi (Ocimum Citriodorum)

2017 ◽  
Author(s):  
Yusnita Rifai
Keyword(s):  
Silver Nanoparticles ◽  
Reduction Method ◽  
Average Particle Size ◽  
Mechanical Effect ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Cubic Crystal ◽  
X Ray ◽  
Speed Up ◽  
And Storage

AbstrakNanopartikel perak telah disintesis menggunakan metode reduksi. Dalam penelitian ini, ekstrak metanol daun Kemangi (Ocimum citriodorum) digunakan sebagai agen pereduksi untuk prekursor AgNO3. Sintesis nanopartikel perak dilakukan dengan mencampurkan laru- tan AgNO3 1mM dengan filtrat ekstrak daun kemangi. Hasil karakterisasi UV-Vis menun- jukkan bahwa nilai absorbansi meningkat dengan meningkatnya waktu kontak reaksi. Pun- cak absorbansi spektrum UV-Vis dari sampel biosintesis nanopartikel perak berkisar pada 427-439 nm selama 1 hari dengan pengadukan dan penyimpanan. Ukuran nanopartikel perak ditentukan menggunakan Pengukur Ukuran Partikel (PSA) dengan rata-rata distribusi uku- ran partikel sebesar 57,38 nm. Efek mekanik dalam proses biosintesis nanopartikel perak cenderung mempercepat pembentukan nanopartikel perak. Hasil karakterisasi menggunakan Difraksi Sinar-X (XRD) diketahui kristalit yang terbentuk memiliki intensitas terbesar pada sudut 38° dengan nilai FWHM 0,66310 (ukuran 0,3 nm) dalam sistem kristal kubik.Kata kunci: Biosintesis, Nanopartikel Perak, Ocimum citriodorum, Karakterisasi AbstractSynthesis of silver nanoparticles by using the reduction method with methanol extract basil (Ocimum citriodorum) leaves, which acted as a reducing agent for AgNO3 precursor have been conducted. Synthesis nanoparticles was carried out by mixing the solution of AgNO3 1mM with filtrate extract of Ocimum leaves. The results of characterization showed that absorbance values increased with the increase in reaction time. Peak of UV-Vis absorption spectrum of biosynthesis sample of silver nanoparticles with stirring and storage each at a wavelength 427-439 nm for 1 day. Silver nanoparticles size was determined by using PSA (Particles Size Analyzer) with an average particle size distribution of 57,38 nm. Mechanical effect in biosynthesis process of silver nanoparticles tends to speed up the formation of silver nanoparticles. The result of characterization by using X-Ray Diffraction (XRD) described that the formed crystal had the angle of 38° with the value of FWHM 0,66310 (sixe 0.3 nm) in cubic crystal system.Key word: Biosynthesis, Silver Nanoparticles, Ocimum citriodorum, Characterization.

Low temperature synthesis of ultrafine LiTaO3 powders

1991 ◽  
Vol 6 (7) ◽  
pp. 1567-1573 ◽  
Author(s):  
Pradeep P. Phulé ◽  
Thomas A. Deis ◽  
David G. Dindiger
Keyword(s):  
Acetic Acid ◽  
Structural Modification ◽  
Glacial Acetic Acid ◽  
Single Phase ◽  
Average Particle Size ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Low Temperature Synthesis ◽  
X Ray ◽  
Gel Network

Controlled chemical polymerization of tantalum ethoxide in the presence of glacial acetic acid (HOAc/Alk. = 16) and solubilized lithium acetate (Li/Ta = 1.00, H2O/Alk. = 55.55) was used for the preparation of an amorphous gel precursor to LiTaO3. Although additional investigations are required, the results suggest that successful formation of amorphous gel network, as opposed to that of colloidal tantalum (hydrous) oxide, may be due to the generation of a new organotantalum precursor via a structural modification reaction between the tantalum ethoxide and glacial acetic acid. The evolution of LiTaO3 ceramics from pre-ceramic gels was investigated using thermal analysis, electron microscopy, and x-ray diffraction. The results indicate that after the completion of gel pyrolysis (200–400 °C) and crystallization (Tc = 590 °C), ultrafine (average particle size 100–300 nm), single phase, crystalline (a = 5.243, c = 13.812 Å) LiTaO3 powders can be prepared at low processing temperatures.

scholarly journals Dielectric properties of BNT-xBT prepared by hydrothermal process

2017 ◽  
Vol 07 (03) ◽  
pp. 1750019 ◽  
Author(s):  
Natheer B. Mahmood ◽  
Emad K. Al-Shakarchi
Keyword(s):  
Strong Dependence ◽  
Average Particle Size ◽  
Hydrothermal Process ◽  
Industrial Applications ◽  
Rhombohedral Structure ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Depolarization Temperature ◽  
X Ray ◽  
Ceramic Disc

The BNT ceramic sample might be a good replacement for PZT piezoelectric in industrial applications, especially in energy harvesting from crystal vibrations. In order to enhance the performance of BNT ceramic, the solid solution was chosen by substitution with Ba[Formula: see text] at Morphtropic Phase Boundary (MPB). The BNT-[Formula: see text]BT powders with [Formula: see text], 0.07, 0.06 and 0 were prepared by the hydrothermal method with average particle size (65–150[Formula: see text]nm) at (90[Formula: see text]C/72[Formula: see text]h). The ceramic disc was sintered at (1150[Formula: see text]C/4[Formula: see text]h) and showed excellent relative density of about 96%. The results of X-ray diffraction (XRD) confirmed the MPB for [Formula: see text] and 0.07, while the BNT had a rhombohedral structure and BT had a tetragonal structure. The dielectric measurements showed that BNT, BNT-7BT, BNT-6BT behave as the relaxator ferroelectric and showed a strong dependence on frequency, especially in the MPB region while BT behaves as a normal ferroelectric. Both the Curie temperature and depolarization temperature decrease at the MPB region and showed strong dependency on frequency.

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