scholarly journals Effects of Variation in Al Content on the Emission of Eu Doped CaAlSiN3 Red Phosphor Synthesized by Combustion Synthesis Method for White LEDs

2021 ◽  
Vol 22 (20) ◽  
pp. 11301
Author(s):  
Shu-Chi Huang ◽  
Shyan-Lung Chung
Keyword(s):  
Combustion Synthesis ◽  
Emission Intensity ◽  
Fine Particles ◽  
Synthesis Method ◽  
Molar Ratio ◽  
X Ray ◽  
White Leds ◽  
Al Content ◽  
Peak Emission Wavelength ◽  
Selected Area Electron Diffraction

Effects of Al content on the formation and the photoluminescence properties of CaAlSiN3:Eu2+ phosphor (CASIN) were investigated by a combustion synthesis method. XRD (X-ray diffraction), combined with PL (photoluminescence), TEM-EDS (transmission electron microscope equipped with an energy-dispersive X-ray spectroscope), and SAED (selected area electron diffraction) measurements, show that the bar-like CASIN gives a stronger emission than the plate-like and agglomerated fine particles. The emission intensity increases as the Al content increased from Al = 0.2 to Al = 0.8, which resulted from the extent of formation of CASIN increases. Then, the emission intensity decreases as the Al content is increased from Al = 0.8 to Al = 1.5, which resulted from the transformation of morphology of CASIN and a large amount formation of AlN. In addition, the extent of formation of CASIN increases with increasing Al from Al = 0.2 to Al = 1.2 and begins to decrease as Al is further increased to 1.5, and thus the peak emission wavelength increases from 647 nm to 658 nm as the Al molar ratio is increased from 0.2 to 1.2 and begins to decrease when further increasing the Al molar ratio to 1.5, which resulted from the large amount of AlN formed.

Low-Temperature Self-Mixing Combustion Synthesis of Spinel LiMn2O4: Effect of Igniting Temperatures

2011 ◽  
Vol 80-81 ◽  
pp. 440-443
Author(s):  
Gui Yang Liu ◽  
Jun Ming Guo ◽  
Bao Sen Wang ◽  
Ying He ◽  
Li Li Zhang
Keyword(s):  
Low Temperature ◽  
Combustion Synthesis ◽  
Reaction Rate ◽  
Raw Materials ◽  
Synthesis Method ◽  
Xrd Analysis ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Higher Temperature

In this paper, a low-temperature self-mixing combustion synthesis method was introduced to prepare spinel LiMn2O4. Low-melting raw materials and fuel (acetate salts as starting materials and urea as fuel) were molten to a homogeneous liquid mixture at ~100°C. The mixture was then ignited and calcined at a higher temperature, final products were obtained. The products were determined by X-ray diffraction (XRD) and scanning electric microscope (SEM). XRD analysis indicated that product with higher purity was obtained at 550°C for 5h when the molar ratio of Li:Mn:urea=1:2:4. The impurity Mn2O3 was appeared in the products when the igniting temperature >600°C, and the content of Mn2O3 increased with the increasing igniting temperatures. SEM investigation indicated that the particles of the products were small and agglomerated. The igniting temperature monitoring indicated that the combustion reaction rate increased with increasing igniting temperature, and this did not favor for the formation of LiMn2O4.

Optimized Preparation of Fe2O3/Al2O3 Composite with Sol-Gel Combustion Synthesis Method Based on Orthogonal Experimental Design

2011 ◽  
Vol 341-342 ◽  
pp. 215-220
Author(s):  
Bao Wen Wang ◽  
Chuan Chang Gao ◽  
Hai Bo Zhao ◽  
Chu Guang Zheng
Keyword(s):  
Experimental Design ◽  
Combustion Synthesis ◽  
Ignition Temperature ◽  
Sintering Temperature ◽  
Sol Gel ◽  
Synthesis Method ◽  
Influential Factor ◽  
Molar Ratio ◽  
Orthogonal Experimental Design ◽  
Gel Combustion

Fe2O3/Al2O3 composite at the mass ratio of 3:2 was prepared by sol-gel combustion synthesis using urea as fuel. The optimized preparation parameters were determined by the robust orthogonal experimental design (OED) method. Standard L9(34) orthogonal array was adopted, and the four factors were determined as the molar ratio of oxidizer nitrates to fuel urea Ф, relative amount of the deionized water added Rw, ignition temperature and sintering temperature. Range analysis of the relative importance of those four factors on the mean weight loss rate for the reduction of synthesized Fe2O3/Al2O3 with 50 vol% H2 indicated that the most influential factor was Ф, sintering temperature, Rw and ignition temperature in the descending order. And the optimized preparation parameters for Fe2O3/Al2O3 composite were Ф=1, Rw=7.5, ignition and sintering temperatures stabilized as 600°C and 950°C,respectively. Finally, the reaction characteristics of Fe2O3/Al2O3 prepared by SGCS and the other two reference methods (including sol-gel method and mechanical mixing method) were compared and the results verified that the optimized SGCS was the best option to synthesize Fe2O3/Al2O3 composite with good reaction performance.

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.

LiAl0.1Mn1.9O4 Prepared by a Solution Combustion Synthesis Using Acetate as Raw Materials and Acetic Acid as Fuel: Effect of Further Calcination Time

2012 ◽  
Vol 485 ◽  
pp. 473-477
Author(s):  
Gui Yang Liu ◽  
Jun Ming Guo ◽  
Li Li Zhang ◽  
Jing Wang ◽  
Bao Sen Wang ◽  
...  
Keyword(s):  
Combustion Synthesis ◽  
Raw Materials ◽  
Synthesis Method ◽  
Solution Combustion Synthesis ◽  
Metal Foil ◽  
X Ray Diffraction ◽  
Calcination Time ◽  
Solution Combustion ◽  
X Ray ◽  
Discharge Capacities

LiAl0.1Mn1.9O4 materials were prepared by a solution combustion synthesis method. In order to improve the purity of the products, the effect of further calcination time was investigated. 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 main phase of the products was LiAl0.1Mn1.9O4, and there was a trace amount Mn2O3 impurity in some of the products. The purity, crystallinity and grain size of the LiAl0.1Mn1.9O4 were increased with increasing further calcination time. Electrochemical experiments demonstrate that the initial discharge capacities of the products with further calcination time of 0, 6, 12 and 24h were 93.7, 105.7, 114.0 and 120.6mAh/g, and about 89.8, 89.5, 89.2 and 88.3% of the initial capacities were retained after 25 cycles, respectively. Further calcination time can enhance the initial capacity, but is not favorable for the cycle ability of the products.

Ni Doped LiMn2O4 Prepared by a Flameless Combustion Synthesis

2012 ◽  
Vol 625 ◽  
pp. 251-254 ◽  
Author(s):  
Gui Yang Liu ◽  
Bao Sen Wang ◽  
Ying He ◽  
Jun Ming Guo
Keyword(s):  
Combustion Synthesis ◽  
Raw Materials ◽  
Synthesis Method ◽  
Solution Combustion Synthesis ◽  
Electrochemical Performances ◽  
X Ray Diffraction ◽  
Galvanostatic Charge ◽  
Solution Combustion ◽  
Limn2o4 Spinel ◽  
X Ray

In this paper, LiNixMn2−xO4 materials were prepared by solution combustion synthesis method using acetic salts as raw materials and acetic acid as fuel. The phase structures are characterized by X-ray diffraction (XRD). Electrochemical performances of the materials are investigated by galvanostatic charge/discharge methods. XRD results revealed that the main phase of the products with increasing Ni3+ content is LiMn2O4, and there is a trace amount of Mn3O4 found in the product with Ni3+ content of 0.05. Electrochemical experiments showed that the capacity and the cyclability of the LiNixMn2−xO4 materials decrease with increasing Ni3+ content. Ni3+ doping has no significantly improvement for the capacity and the cyclability of the LiMn2O4 spinel.

scholarly journals ONE-STEP SYNTHESIS OF POLYMETALLIC NANOPARTICLES IN AIR INVIRONMENT

2018 ◽  
Vol 61 (9-10) ◽  
pp. 42-47 ◽  
Author(s):  
Valentin I. Romanovsky ◽  
Alexander A. Hort ◽  
Kirill B. Podbolotov ◽  
Nikolay Yu. Sdobnyakov ◽  
Vladimir S. Myasnichenko ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Metal Oxide ◽  
Combustion Synthesis ◽  
Synthesis Method ◽  
Solution Combustion Synthesis ◽  
Solution Combustion ◽  
X Ray ◽  
Transmission Electron ◽  
One Step

In this work, we studied possibility to obtain bimetallic nanopowders by our modified solution combustion synthesis method using citric acid as a fuel. Stoichiometric amounts of metal nitrates with metal to metal ratios 1:1 and 1:2 and fuels with final oxidizer to fuel ratio of 1.75 were used as initial components to prepare aqueous solutions. The almost complete absence of metal oxide phases was confirmed by energy-dispersive X-ray spectroscopy. The X-ray diffraction analysis of obtained materials showed that all samples are pure bimetallic nanopowders with distorted cubic crystal structure of each metal. According to high resolution transmission electron microscopy the mean diameter of metallic particles are about 10 nm for all nanopowders. The calculated interplanar distances of crystals of metal particles as well as detailed scanning transmission electron microscopy studying showed uniform distribution of different metal spices into nanoparticles. Thus, we can conclude the nanopowders are bimetallic particles with co-integrated crystal structures of different metalic spices. We suppose, the possibility of solution combustion synthesis of bimetallic nanopowder in the air environment is due to a combination of type and amount of the fuels as well as technological conditions of the synthesis. These lead to rapid combustion process at low temperature. In addition, protective inert atmosphere appears above freshly synthesized metal nanopowders during thermal decompositions of the fuels that eventually prevent metal oxidation. Modified SCS method could be successfully used for one-step synthesis of complex oxide-oxide and metal-oxide core-shell nanostructures. For citation: Romanovskii V.I., Khort A.A., Podbolotov K.B., Sdobnyakov N.Y., Myasnichenko V.S., Sokolov D.N. One-step synthesis of polymetallic nanoparticles in air invironment. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 9-10. P. 42-47

scholarly journals Oxalic Acid-Assisted Hydrothermal Synthesis and Luminescent of Hexagonal NaYF4:Ln3+ (Ln = Sm, Eu, Yb/Er) Micro/Nanoplates

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Feng Tao ◽  
Zhishun Shen ◽  
Zhijun Wang ◽  
Da Shu ◽  
Qi Liu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Oxalic Acid ◽  
Molar Ratio ◽  
Photoluminescence Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ph Values ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Display Systems

Hexagonal NaYF4:Ln3+ micro/nanoplates were successfully synthesized via a hydrothermal method using oxalic acid as a shape modifier. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and selected area electron diffraction (SAED) have been used to study the morphologies and crystal structure of the products. The effects of the pH values and the molar ratio of oxalic acid to NaOH on the crystal growth have been investigated in detail. The time-dependent experiments have been conducted to investigate the morphology evolution process, and based on the results, a possible growth mechanism was proposed. The photoluminescence properties of 5 mol% Eu3+ and 3 mol% Sm3+ doped NaYF4 and 20 mol% Yb3+/2 mol% Er3+ codoped NaYF4 micro/nanoplates were investigated. The experimental results showed that NaYF4:Ln3+ micro/nanoplates have excellent luminescence and can be potential application in the field of light display systems, lasers, and optoelectronic devices.

Interfacial Synthesis of SiO2 Doped by Polyaniline and its Electrorheological Behavior

2011 ◽  
Vol 179-180 ◽  
pp. 249-252
Author(s):  
Qing Ming Jia ◽  
Shao Yun Shan ◽  
Li Hong Jiang ◽  
Ya Ming Wang
Keyword(s):  
Silicone Oil ◽  
Synthesis Method ◽  
Tetraethyl Orthosilicate ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
One Pot ◽  
X Ray ◽  
Sem Image ◽  
Interfacial Synthesis ◽  
Er Fluid

SiO2 doped by polyaniline for application in electrorheological (ER) fluid was prepared by using a simple one-pot interfacial synthesis method. Scanning electron microscopy (SEM) image shows that the morphologies of SiO2 may be changed from spherical to fibroid structure by changing the molar ratio of tetraethyl orthosilicate(TEOS) and aniline. X-ray diffraction (XRD) proves that polyaniline does not change the crystallinity of SiO2. The ER behaviors of SiO2 doped by polyaniline in silicone oil are investigated with different doping degrees under different shear rate, and the results show that properly doping polyaniline improves electrorheological behavior of SiO2.

Nitrogen Doped and Functionalized Carbon Materials as Supports for Catalysts in Electro-Oxidation of Methanol

2014 ◽  
Vol 93 ◽  
pp. 41-49 ◽  
Author(s):  
M.J. Lázaro ◽  
C. Alegre ◽  
M.J. Nieto-Monge ◽  
D. Sebastián ◽  
M.E. Gálvez ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Carbon Materials ◽  
Synthesis Method ◽  
Electrochemical Analysis ◽  
Molar Ratio ◽  
Synthesis Process ◽  
X Ray ◽  
Nitrogen Doped ◽  
Oxidation Of Methanol ◽  
Electro Oxidation

The objective of this work is to study the behavior of Nitrogen-doped carbons as supports of catalysts for the electro-oxidation of methanol. Two carbon materials have been considered: a) carbon xerogels (CXG), highly mesoporous, whose porosity and pore size distribution are easily performed during the synthesis method; b) carbon nanofibers (CNF), which have a high electrical conductivity, good behavior in high temperature conditions and resistance to acid/basic media. Meanwhile, a commercial carbon black (Vulcan XC72R) which is commonly used in manufacturing of electrocatalysts fuel cells was used for comparison. Nitrogen was introduced into the CXG during the synthesis process, what is commonly referred as doping, by including melamine as a reactant. In contrast, N-groups were created over CNF by post-treatment with: ammonia (25%), urea (98%), melamine (99%) and ethylenediamine (99.5%), with a carbon: nitrogen molar ratio 1:0.6. N-containing carbon materials were characterized by elemental analysis, nitrogen adsorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), SEM-EDX and TEM to determinate the amount and forms of nitrogen introduced. Pt-catalysts were prepared by the microemulsion method. The influence of the nitrogen doping and functionalization on the catalytic behavior in the electrochemical oxidation of methanol was evaluated by different physicochemical and electrochemical analysis.

scholarly journals A Physical Chemistry Study of Black Powder Materials by Solution Combustion Synthesis Method

2021 ◽  
Vol 10 (2) ◽  
pp. 93-103
Author(s):  
Fitria Hidayanti ◽  
Kiki R. Lestari ◽  
Nano Sujani ◽  
Jarot Raharjo
Keyword(s):  
Combustion Synthesis ◽  
Lanthanum Oxide ◽  
Synthesis Method ◽  
Solution Combustion Synthesis ◽  
Synthesis Temperature ◽  
Powder Sample ◽  
Synthesis Process ◽  
Solution Combustion ◽  
Black Powder ◽  
X Ray

A study on the synthesis of black powder (La2NiO4) material using the solution combustion synthesis method at a variation of synthesis temperature of 60, 70, and 80°C was carried out. It produces a mass of black powder of 2 grams by four times of synthesis process. Then, material characterization was performed on the black powder samples obtained by using X-ray Diffraction (XRD) to determine the phases formed, Scanning Electron Microscopy - Energy Dispersive X-ray Spectroscopy (SEM-EDS) to determine the morphology and analyze the composition elemental on the microscale and Fourier Transform Infra-Red (FTIR) to determine chemical bonds. From the whole black powder sample, XRD analysis showed the phases of Dilantanum Nickel Tetraoxide (La2NiO4), Nickel Oxide (NiO), Lanthanum Oxide (La2O3), and Lanthanum Oxide Ht x-form (La2O3 Ht (x-form)). In addition, it was seen from the visible compositions of the phases that the NiO phase looks more dominant and the variation of the synthesis temperature shows that the La2O3 phase was increasing. This was supported by the EDS analysis, which showed that the EDS spectrum contains elements La, Ni, and O where the element O indicates that oxidation occurs in the elements Ni and La. On the other hand, the SEM analysis results confirm that the black powder sample contains the elements La and Ni, based on the high and low electron images contained in the morphology of the black powder sample. In addition, it was also known that the particles in the black powder sample were micron size and had porous morphology. This occurs due to rapid thermal decomposition events and excessive gas development. In addition, FTIR analysis showed that the O-H bond had been reduced and there are still C-O and C-H bonds indicating the presence of organic elements possessed by glycine.

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