LiMn2O4 nanopowders synthesized via gelatin-assisted sol–gel method: Optimization of pH and calcination temperature

2019 ◽  
Vol 33 (08) ◽  
pp. 1950063
Author(s):  
Nasrin Azad ◽  
Hadi Arabi ◽  
Shaban Reza Ghorbani ◽  
Ali Davodi
Keyword(s):  
Calcination Temperature ◽  
Ph Value ◽  
Sol Gel ◽  
Chelating Agent ◽  
The Other ◽  
Effect Of Temperature ◽  
Gel Method ◽  
Sol Gel Method ◽  
The Fourier Transform ◽  
The Stability

In this research, LiMn2O4 nanopowders were synthesized via sol–gel method using gelatin as a novel chelating agent. The effect of temperature and pH on the structure, morphology and particle size of synthesized powders has been investigated by the differential thermal analysis (DTA), the X-ray diffraction (XRD), the Fourier transform infrared (FTIR) and the field-emission scanning electron microscope (FESEM). The crystal structure of LiMn2O4 was completely formed without any impurity phase at a calcination temperature of 750[Formula: see text]C. The peak intensity ratio of I[Formula: see text]/I[Formula: see text], which presents the stability of LiMn2O4 structure, is bigger for the sample with pH[Formula: see text]=[Formula: see text]4 than that of the samples with pH[Formula: see text]=[Formula: see text]7 and 8. The sample with pH[Formula: see text]=[Formula: see text]4 has smaller particles of about 70 nm, with more homogeneity and less agglomeration than that of the other samples. At calcination temperature to 850[Formula: see text]C, the size of the particles has become bigger and the particle surfaces show more clarity in all samples. The effect of the pH value on electrochemical properties was studied by galvanostatic charge/discharge tests. The results show more capacity lost for the sample with pH[Formula: see text]=[Formula: see text]8 with regards to the other samples.

Preparation and Morphological Controlling of Nanophase NaNbO3 by Sol-Gel Method

2008 ◽  
Vol 368-372 ◽  
pp. 140-143 ◽  
Author(s):  
Ying Lin ◽  
Hai Bo Yang ◽  
Fen Wang
Keyword(s):  
Metal Ion ◽  
Ph Value ◽  
Sol Gel ◽  
Chelating Agent ◽  
Gel Method ◽  
Sol Gel Method ◽  
Forming Mechanism ◽  
Water As Solvent ◽  
Rapid Temperature ◽  
The Stability

With citric acid as chelating agent, ethylene alcohol as etherification agent and water as solvent, NaNbO3 nanopowder was synthesized by citrate sol-gel method. The effects of amount of CA and EG, pH value on the stability of the precursor sol were investigated. The evolution of NaNbO3 crystal phase was also investigated by XRD and TG-DTA. The results showed that a homogeneous precursor sol was formed at in the case of n(CA) : n(metal ion)=3:1, n(CA) : n(EG)=1: 2 and 1:3 and pH=7.5. Sintering process largely influences the morphology of the prepared products. Grain-like nanoparticles could be obtained with a rapid temperature rising rate, while nanorods were obtained with a slow rate. The forming mechanism of different morphologies of the prepared nanoparticles was also discussed.

scholarly journals Effect of pH and annealing temperature on the structural and magnetic properties of cerium-substituted yttrium iron garnet powders produced by the sol-gel method

2016 ◽  
Vol 34 (2) ◽  
pp. 362-367 ◽  
Author(s):  
I. Yarici ◽  
M. Erol ◽  
E. Celik ◽  
Y. Ozturk
Keyword(s):  
Magnetic Properties ◽  
Yttrium Iron Garnet ◽  
Annealing Temperature ◽  
Ph Value ◽  
Sol Gel ◽  
Chelating Agent ◽  
Yttrium Iron ◽  
Gel Method ◽  
Sol Gel Method ◽  
Iron Garnet

AbstractCerium substituted yttrium iron garnet (Ce0.2Y2.8Fe5O12; Ce-YIG) nanoparticles were produced via the sol-gel method from solutions of Ce-, Y- and Fe-based precursors, a solvent and a chelating agent. The solutions were dried at 200°C and heat treated at temperatures between 800 °C and 1400°C for 3 h in air. The effects of pH and annealing temperature on the structure, phase formation, magnetic properties and crystallite size were investigated. A cubic YIG phase was obtained for the sample annealed at 1400 °C. The presented results showed that the pH value of the starting solution affects the crystal size and consequently, the saturation magnetization.

SOL-GEL SYNTHESIS AND CHARACTERIZATION OF COPPER STABILIZED ZIRCONIA NANOPARTICLES

2011 ◽  
Vol 25 (21) ◽  
pp. 2823-2839 ◽  
Author(s):  
Y. VAHIDSHAD ◽  
H. ABDIZADEH ◽  
H. R. BAHARVANDI ◽  
M. AKBARI BASERI
Keyword(s):  
Particle Size ◽  
Hydrogen Production ◽  
Calcination Temperature ◽  
Aging Temperature ◽  
Sol Gel ◽  
Chelating Agent ◽  
Molar Ratio ◽  
Gel Method ◽  
Sol Gel Method ◽  
Sol Gel Synthesis

A sol-gel method is investigated to synthesize CuO – ZrO 2 nanoparticles as catalyst for hydrogen production from methanol. Finer precursor nanoparticles give rise to larger specific areas in catalyst which result in a high hydrogen production. The effects of some critical process parameters on the sol-gel synthesis of CuO – ZrO 2 nanoparticles are studied. These parameters are affected on synthesis of CuO – ZrO 2 when it is prepared with sol-gel method. Particle size and distribution are considered as the results. The parameters including the effect of calcination temperature, aging temperature, nature and concentration of catalyst (acidic or basic conditions), H 2 O /precursor molar ratio, and chelating agent that have been identified as most important, are focused. It is found that the calcination temperature strongly influenced the morphology and interaction between the active species and support, and hence the structure and catalytic performance. Nature and concentration of catalyst ( pH value), chelating agent, ( H 2 O /precursor) molar ratio and also aging temperature have influence on the nanoparticles. Thus, by controlling these factors, it is possible to vary the morphology and properties of the sol-gel-derived inorganic network over wide ranges. Morphology, particle size and distribution, phase evaluation, structure, and chemical analysis of the products are investigated by SEM, TEM, DTA/TG, XRD and EDX respectively.

Effect of Synthesis Conditions on the Preparation of Ag/ZnTiO3 via Sol-Gel Method and its Antibacterial Properties

2020 ◽  
Vol 1007 ◽  
pp. 47-51
Author(s):  
Huynh Tuyet Anh Le ◽  
Tuan Anh Nguyen ◽  
Ky Phuong Ha Huynh
Keyword(s):  
Ethylene Glycol ◽  
Calcination Temperature ◽  
Ph Value ◽  
Sol Gel ◽  
Antibacterial Properties ◽  
Calcination Time ◽  
Gel Method ◽  
Sol Gel Method ◽  
Synthesis Conditions ◽  
Antibacterial Materials

Antibacterial materials based on nanotechnology have been attracted considerable attention by the scientific community. In this study, the sol-gel method was applied to prepare of antibacterial materials from tetra-n-butyl orthotitanate, zinc nitrate and ethylenediamine tetraacetic acid (EDTA) as a complexing agent. The effects of the synthesis conditions on the properties of the Ag/ZnTiO3 samples such as the calcination temperature, the calcination time, pH value and ethylene glycol volume, were investigated. The obtained materials were characterized by powder X-ray diffraction (XRD) and their antibacterial activity against Staphylococcus aureus (S. Aureus) was evaluated. The results showed that the optimum conditions for Ag/ZnTiO3 synthesis were: calcination temperature of 650°C, calcination time of 2 h, pH value of 4.5 and ethylene glycol volume of 4.5 mL.

scholarly journals Bismuth Oxide Prepared by Sol-Gel Method: Variation of Physicochemical Characteristics and Photocatalytic Activity Due to Difference in Calcination Temperature

2020 ◽  
Vol 21 (1) ◽  
pp. 108
Author(s):  
Yayuk Astuti ◽  
Brigita Maria Listyani ◽  
Linda Suyati ◽  
Adi Darmawan
Keyword(s):  
Photocatalytic Activity ◽  
Band Gap ◽  
Calcination Temperature ◽  
Bismuth Oxide ◽  
Sol Gel ◽  
Physicochemical Characteristics ◽  
Band Gap Energy ◽  
Gel Method ◽  
Sol Gel Method ◽  
Body Center Cubic

Research on synthesis of bismuth oxide (Bi2O3) using sol-gel method with varying calcination temperatures at 500, 600, and 700 °C has been done. This study aims to determine the effect of calcination temperature on the characteristics of the obtained products which encompasses crystal structure, surface morphology, band-gap energy, and photocatalytic activity for the decolorization of methyl orange dyes through its kinetic study. Bismuth oxide prepared by sol-gel method was undertaken by dissolving Bi(NO3)3·5H2O and citric acid in HNO3. The mixture was stirred then heated at 100 °C. The gel formed was dried in the oven and then calcined at 500, 600, and 700 °C for 5 h. The obtained products were a pale yellow powder, indicating the formation of bismuth oxide. This is confirmed by the existence of Bi–O and Bi–O–Bi functional groups through FTIR analysis. All three products possess the same mixed crystal structures of α-Bi2O3 (monoclinic) and γ-Bi2O3 (body center cubic), but their morphologies and band gap values are different. The higher the calcination temperature, the larger the particle size and the smaller the band gap value. The accumulative differences in characteristics appoint SG700 to have the highest photocatalytic activity compared to SG600 and SG500 as indicated by its percent degradation value and decolorization rate constant.

The Research on ODS Iron Powder by Sol-Gel Method

2012 ◽  
Vol 476-478 ◽  
pp. 1146-1149 ◽  
Author(s):  
Xiao Yu ◽  
Zhi Meng Guo ◽  
Jun Jie Hao ◽  
Wei Wei Yang
Keyword(s):  
Mechanical Alloying ◽  
Iron Powder ◽  
Ferritic Steel ◽  
Ph Value ◽  
Sol Gel ◽  
Oxide Dispersion Strengthened ◽  
Steel Powder ◽  
Raw Material ◽  
Gel Method ◽  
Sol Gel Method

Oxide dispersion strengthened (ODS) ferritic steel which contains Y2O3 dispersion is one of the most promising candidates for fast neutron reactor cladding materials due to its excellent swelling resistance to neutron and superior creep resistance in high temperature. There are many ways to prepare ODS ferritic steel and the most commonly used method is mechanical alloying. However, ODS ferritic steel produced by the method of mechanical alloying is poor in the plasticity and impact property. Moreover, the anisotropies of structure and properties are obvious in the follow-up processing. In this paper, in order to reduce the cost, iron powder is used as raw material instead of ferritic steel powder. The complexing sol-gel method is adopted to prepare ODS iron-powder. There are many advantages of the sol-gel method such as the small size of disperse phase and the high uniformity. Besides, it is easy to control the conditions of reaction such as the water content, the bath temperature and the PH value. The gel-coated iron powder can be prepared under the appropriate environmental conditions. Then, we can obtain iron powder with Y2O3 dispersion after heating and reducing the gel-coated iron powder. By the spark plasma sintering(SPS), the ODS iron powder can be densified and we can observe the microstructure and test the performance. The results reveal the Y2O3 dispersion of ODS iron-powder by sol-gel method is uniform and the mechanical property is excellent.

Fabrication of Bi-2223 Powders Using Sol-Gel Method

2011 ◽  
Vol 412 ◽  
pp. 125-128 ◽  
Author(s):  
Ming Ya Li ◽  
Xiao Yan Wang ◽  
Cheng Li Ye ◽  
Feng Lin Xue
Keyword(s):  
Heat Treatment ◽  
Sol Gel ◽  
Chelating Agent ◽  
Experimental Results ◽  
Main Phase ◽  
Gel Method ◽  
Sol Gel Method ◽  
Dwelling Time ◽  
Metal Nitrates ◽  
Gel Technique

The Bi-2223 powders were fabricated by the sol-gel technique. Metal nitrates were used as starting materials, and ethylenediamineteracetic acid was used as chelating agent. The solution was heated until it turns to gel. Then the organic was removed at a temperature of 240°C, and the nitrite was removed at 500°C. The powder was calcined at different temperature, varying the dwelling time. Experimental results show that the main phase of samples after heat treatment is Bi-2212 phase.

DIFFERENT MORPHOLOGIES OFTiO2NANOSTRUCTURES IN ACIDIC AND BASIC SOL–GEL METHOD

NANO ◽  
2010 ◽  
Vol 05 (05) ◽  
pp. 279-285 ◽  
Author(s):  
M. H. IMANIEH ◽  
Y. VAHIDSHAD ◽  
P. NOURPOUR ◽  
S. SHAKESI ◽  
K. SHABANI
Keyword(s):  
Ph Value ◽  
Sol Gel ◽  
Simple Method ◽  
Gel Method ◽  
Sol Gel Method ◽  
New Process ◽  
Nanocrystalline Titanium ◽  
Acidic Conditions ◽  
Nanocrystalline Titanium Dioxide ◽  
First Time

In this research, nanocrystalline titanium dioxide (TiO2) particles were prepared by a modified alkoxide technique under basic and acidic conditions at room temperatures. A simple method for preparing different morphology of TiO2has been developed. The reaction condition was used to control the crystalline size, phase and morphology of the TiO2nanostructures. In this process by adjusting the Rw(water to precursor ratio) and pH value the hydrolysis and condensation reactions were controlled. This led to the development of a new process to produce TiO2nanorod (for the first time by sol–gel method) at high pH value (basic) while the water content was sufficient whereas at low pH value (acidic) nanosphere TiO2were obtained. The powders were characterized by DTA, XRD, FE-SEM and UV–vis techniques and their physical properties were compared.

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