scholarly journals Effect of Calcination Temperature and Li / TFA Molar Ratio on Morphology and Phase of Lithium Fluoride Nanoparticles Produced by Fluorolytic Sol-Gel Method

2019 ◽  
Vol 38 (03) ◽  
2011 ◽  
Vol 412 ◽  
pp. 223-226 ◽  
Author(s):  
Wei Hui Jiang ◽  
Yan Hui Yang ◽  
Qing Xia Zhu ◽  
Jian Min Liu

ron-zircon pigment has been synthesized by non-hydrolytic sol-gel method using zirconium chloride and tetraethoxysilane as precursors, anhydrous ferric chloride as colorant, lithium fluoride as mineralizer and anhydrous ethanol as solvent. Iron-zircon pigment has been characterized by means of DTA-TG, XRD, Colorimeter and TEM. The results show that only a small fraction of iron is incorporated in the zircon crystal structure while the remaining iron cations are trapped within the zircon matrix. The iron-zircon with the red value (a*) of 20.64 can be synthesized at 700°C with the optimum Fe/Zr molar ratio of 0.2.


2011 ◽  
Vol 25 (21) ◽  
pp. 2823-2839 ◽  
Author(s):  
Y. VAHIDSHAD ◽  
H. ABDIZADEH ◽  
H. R. BAHARVANDI ◽  
M. AKBARI BASERI

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.


2014 ◽  
Vol 875-877 ◽  
pp. 251-256 ◽  
Author(s):  
Lin Sun ◽  
Rong Shao ◽  
Lan Qin Tang ◽  
Zhi Dong Chen

Ag/ZnO nanocomposite photocatalysts with high photocatalytic performance were successfully synthesized via a facile sol-gel method. The prepared Ag/ZnO products were characterized by XRD, SEM, EDS, FT-IR, BET surface area, TG and DSC. Photodegradation experiments of the samples were carried out by choosing Methylene Blue (MB) as a model target under UV irradiation with homemade photocatalytic apparatus. Among these products, when the molar ratio of Ag to ZnO was fixed at 0.07 and the calcination temperature was around 450 °C, the obtained samples exhibited the highest photocatalytic activity.


2020 ◽  
Vol 21 (1) ◽  
pp. 108
Author(s):  
Yayuk Astuti ◽  
Brigita Maria Listyani ◽  
Linda Suyati ◽  
Adi Darmawan

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.


2002 ◽  
Vol 17 (3) ◽  
pp. 590-596 ◽  
Author(s):  
G. Ennas ◽  
M. F. Casula ◽  
G. Piccaluga ◽  
S. Solinas ◽  
M. P. Morales ◽  
...  

γ–Fe2O3/SiO2 and Fe/SiO2 nanocomposites, with a Fe/Si molar ratio of 0.25, were prepared by the sol-gel method starting from ethanolic solutions of tetraethoxysilane and iron (III) nitrate. After gelation the xerogels were oxidated or reduced. Samples were investigated by transmission electron microscopy, x-ray diffraction, differential scanning calorimetry, and thermogravimetry. Magnetic properties of the samples were investigated at room temperature (RT) and at 77 K. Nanometric particles supported in the silica matrix were obtained in all cases. Bigger particles (10 nm) were obtained in the case of Fe/SiO2 nanocomposites with respect to the γ–Fe2O3/SiO2 samples (5–8 nm). A slight effect of sol dilution on particle size was observed only in the case of γ–Fe2O3/SiO2 nanocomposites. A superparamagnetic behavior was shown at RT only by γ–Fe2O3/SiO2 nanocomposites. Iron-based composites exhibited coercivity values higher than 700 Oe at RT.


2011 ◽  
Vol 393-395 ◽  
pp. 1287-1290
Author(s):  
Min Wang ◽  
Qiong Liu ◽  
Qi Xing

The N-doped Cu11O2 (VO4)6 photocatalyst was prepared using the sol-gel method. Techniques of X-ray diffraction (XRD), scanning electron microscope (SEM) have been employed to characterize the as-synthesized materials. During liquid phase photocatalytic degradation of Methy lorange(MO) under the UV-light, the as-prepared N-doped Cu11O2 (VO4)6 exhibits higher activity than the pure Cu11O2 (VO4)6 without doped N. It found that the N-doped Cu11O2 (VO4)6 prepared with the molar ratio of citric acid to metal inons be 2:1, N/Cu molar ratio of 12%, pH=7 and calcinated under 500°C for 4 hours was pure triclinic phase. In this conditions, the sample had highest photocatalytic activity with the photodegradation rate was about 94.42% or so in 60min under 20W ultraviolet lamp.


2014 ◽  
Vol 977 ◽  
pp. 59-62 ◽  
Author(s):  
Jun Qing Tian ◽  
Hai Ying Shi ◽  
Wei Zheng

Fluorine-doped tin dioxide (FTO) nanocrystals were prepared with sol–gel method using SnCl4·5H2O and NH4F as precursor material. The FTO was characterized with X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Differential Thermal Analysis and Thermal Grativity (DTA-TG) and Infrared Radiation (IR) respectively. The electrical property was measured with Hall Effect Sensor. The result of XRD and SEM shows that FTO nanocrystal size is about 20 nm and the dimension of the grain is about 300 nm. IR spectrum analysis proves fluorine doping. The crystal phase transformation was discussed with DTA-TG curve. When the sintering temperature is 450°C, the sintering time is 60 min, and the molar ratio of F to Sn is 2:10, the sheet resistance of FTO film is 107Ω/□.


2010 ◽  
Vol 8 (1) ◽  
pp. 47-53
Author(s):  
Haryo Satriya Oktaviano ◽  
Wega Trisunaryanti

Cobalt and nickel based catalysts for ethanol steam reforming have been prepared. Preparation of Na-Ni-Mo/C, Na-Co-Mo/C, K-Ni-Mo/C and K-Co-Mo/C have been carried out using sol-gel method by applying citric acid as complexion agent and source for support formation. Prepared catalyst via sol gel showed tailored morphological properties signed by tailored pore size distribution. The acidity of catalyst showed that all catalysts contain only Lewis acid site. The catalyst activity test was conducted by using semi flow method with molar ratio of ethanol : water = 0.33 at 400 oC   Keywords: sol-gel method, steam reforming, ethanol


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