Synthesis and Characterization of LiMn2O4 Nanoparticles Using Citric Acid as Chelating Agent

2009 ◽  
Vol 67 ◽  
pp. 227-232 ◽  
Author(s):  
Gurpreet Singh ◽  
Amrish Panwar ◽  
Anjan Sil ◽  
Sudipto Ghosh

Nanocrystalline LiMn2O4 powder was synthesized by sol-gel method using citric acid as a chelating agent. The powders were characterized by X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), Differential scanning calorimetry (DSC), Differential thermal analysis (DTA), Impedance spectroscopy (IS) and Electrochemical measurements. The powder particles having slight agglomeration characteristics were found to have prismatic morphology and a wider size distribution from 50 nm to 200 nm, which provides good packing density of the material. The electrical conductivity of the powder at room temperature is in the order of ~10-5 S/cm. The structural stability of LiMn2O4 cubic spinel over the temperature range of battery operation was assessed. Electrochemical performance of the material shows a discharge capacity of ~130 mAh/gm.

Molecules ◽  
2020 ◽  
Vol 25 (23) ◽  
pp. 5552
Author(s):  
Ryota Kudo ◽  
Masahiro Sonobe ◽  
Yoshiaki Chino ◽  
Yu Kitazawa ◽  
Mutsumi Kimura

The synthesis and characterization of two phthalocyanine (Pc) structural isomers, 1 and 2, in which four 2,6-di(hexyloxy)phenyl units were attached directly to the 1,8,15,22- or 1,4,15,18-positions of the Pc rings, are described. Both Pcs 1 and 2 exhibited low melting points, i.e., 120 and 130 °C respectively, due to the reduction in intermolecular π-π interaction among the Pc rings caused by the steric hindrance of 2,6-dihexyloxybenzene units. The thermal behaviors were investigated with temperature-controlled polarizing optical microscopy, differential scanning calorimetry, powder X-ray diffraction, and absorption spectral analyses. Pc 1, having C4h molecular symmetry, organized into a lamellar structure containing lateral assemblies of Pc rings. In contrast, the other Pc 2 revealed the formation of metastable crystalline phases, including disordered stacks of Pcs due to rapid cooling from a melted liquid.


2017 ◽  
Vol 31 (02) ◽  
pp. 1750006 ◽  
Author(s):  
Mohammad Hossein Ghorbani ◽  
Abdol Mahmood Davarpanah

Manganese oxides are of more interest to researchers because of their ability as catalysts and lithium batteries. In this research, MnO2nanowires with diameter about 45 nm were synthesized by sol–gel method at room temperature (RT). Effect of increasing the annealing temperature from 400[Formula: see text]C to 600[Formula: see text]C on crystalline structure of nanostructure were studied and average crystallite size was estimated about 22 nm. X-ray Diffraction (XRD) method, Energy-Dispersive X-ray Diffraction (EDXD), Scanning Electron Microscopy (SEM) and Vibrating Sample Magnetometer (VSM) were used to characterize the nanowires of MnO2.


2010 ◽  
Vol 44-47 ◽  
pp. 2136-2139
Author(s):  
Dong Zhang

Nano-calcium titanate-based coated aluminum oxide (ACCTO) was successfully prepared by the citrate acid sol-gel method and characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Its application in speciation of Cr(III) and Cr(VI) from water was studied. The conditions of adsorption and elution were investigated. The results show that nanometer calcium titanate could be immobilized on the aluminum oxide firmly, becoming a composite adsorbent. Two forms of chromium showed different adsorption capability at different pH values, Cr (III) selectively retained at pH 8-14, whereas Cr (VI) retained at pH≤2. So separation of the Cr(III) and Cr(VI) is possible. Retained species were eluted with 5mL of 1 mol•L-1 HCl and NaOH. The Cr(III) and Cr(VI) concentration was measured by atomic absorption spectroscopy. The adsorption agent has a promising prospect in removal or enriching and separation of Cr(III) and Cr(VI) in water.


2014 ◽  
Vol 602-603 ◽  
pp. 19-22 ◽  
Author(s):  
Lin Qiang Gao ◽  
Hai Yan Chen ◽  
Zhen Wang ◽  
Xin Zou

Nanoscale LiTaO3 powders with perovskite structure were synthesized using the solvothermal technique with glycol as solvent at 240°C for 12h. The powders were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). XRD was used to elucidate room temperature structures using Rietveld refinement. The powders were pure single pervoskite phase with high crystallinity. FESEM and TEM were used to determine particle size and morphology. The average LiTaO3 grain size was estimated to be < 200nm, and TEM images indicated that LiTaO3 particles had a brick-like morphology. In addition, the effect of the temperature on the LiTaO3 power characterisitics was also detailed studied.


2016 ◽  
Vol 71 (12) ◽  
pp. 1199-1209
Author(s):  
Vera A. Hartdegen ◽  
Maximilian S. Hofmayer ◽  
Konstantin Karaghiosoff ◽  
Thomas M. Klapötke

AbstractOn the basis of 1,2-bis(5-tetrazolo)ethane (BTE) the corresponding twofold vinyl and allyl N-substituted derivatives were synthesized using 1,2-dibromoethane and allyl bromide, respectively. The compounds were obtained as two different constitutional isomers. Both species were analyzed using NMR and IR spectroscopy, elemental analysis, as well as mass spectrometry. In the case of the diallyl bistetrazoles, the two isomers were characterized using 2D NMR spectroscopy. The synthesis of the divinyl compounds gave crystals of the 2,2′-N-substituted isomer, which were analyzed by single-crystal X-ray diffraction. The thermal stability of the compounds was determined using differential scanning calorimetry (DSC) and gave decomposition temperatures around 190°C and 230°C. For the investigation of the inherent energetic potential, sensitivities toward physical stimuli and detonation parameters were determined. The compounds turned out to be insensitive toward friction and impact and possess moderate energetic properties.


2015 ◽  
Vol 15 (1) ◽  
pp. 36-42 ◽  
Author(s):  
Posman Manurung ◽  
Rudy Situmeang ◽  
Ediman Ginting ◽  
Indra Pardede

This article describes the synthesis of titania-silica composites by a sol-gel method using a mixture of silica of rice husk and titanium butoxide sols. Microstructures were examined at calcination temperature in the range of 500 to 700 °C, with temperatures interval of 50 °C. The sintered catalysts were subsequently tested for photodegradation of methylene blue (MB) under ultraviolet and sunlight rays. Physical characteristics were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM)/energy dispersive X-ray spectroscopy (EDS), and Brunauer-Emmett-Teller (BET). The XRD results did not show the presence of silica crystal phase in each sample. The results showed that the highest BET surface area of samples was obtained at the temperature of 650 °C. In sample calcined 500 °C, the activity of the catalyst on MB was relatively similar in both sunlight and ultraviolet rays.


Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1955 ◽  
Author(s):  
Karina del Ángel-Sánchez ◽  
César I. Borbolla-Torres ◽  
Luis M. Palacios-Pineda ◽  
Nicolás A. Ulloa-Castillo ◽  
Alex Elías-Zúñiga

This paper focuses on developing, fabricating, and characterizing composite polycaprolactone (PCL) membranes reinforced with titanium dioxide nanoparticles (NPs) elaborated by using two solvents; acetic acid and a mixture of chloroform and N,N-dimethylformamide (DMF). The resulting physical, chemical, and mechanical properties of the composite materials are studied by using experimental characterization techniques such as scanning electron microscopy (SEM), differential scanning calorimetry (DSC), X-ray diffraction (XRD), Fourier-transform infrared (FTIR) analysis, contact angle (CA), uniaxial and biaxial tensile tests, and surface roughness measurements. Experimental results show that the composite material synthesized by sol-gel and chloroform-DMF has a better performance than the one obtained by using acetic acid as a solvent.


2020 ◽  
Vol 10 (2) ◽  
pp. 123-126
Author(s):  
Debasish Aich ◽  
Pijus Kanti Samanta ◽  
Satyajit Saha ◽  
Tapanendu Kamilya

Background: Iron oxide (γ-Fe2O3) nanoparticles have been prepared by a simplified coprecipitation method. Methods: X-ray diffraction peaks of the prepared nanoparticles match well with the characteristic peaks of crystalline g-Fe2O3 as per JCPDS data (JCPDS Card No. 39-1346) and absorption peak at 369 nm along with band gap 2.10 eV suggesting the formation of (γ-Fe2O3) nanoparticles. Results: The γ-Fe2O3 nanoparticles are spherical in nature with a diameter around ~10 nm. Conclusion: The crystalline g-Fe2O3 nanoparticles exhibit excellent super-paramagnetic behavior not only at room temperature (300K) but also at a temperature as low as 100K.


2018 ◽  
Vol 273 ◽  
pp. 140-145 ◽  
Author(s):  
Dewi Suriyani Che Halin ◽  
Norsuria Mahmed ◽  
Mohd Arif Anuar Mohd Salleh ◽  
A.N. Mohd Sakeri ◽  
Kamrosni Abdul Razak

Ag/TiO2thin films were prepared via sol-gel spin coating method. Structural, surface morphology and optical properties were investigated with the addition of two different amount of silver (Ag). X-ray diffraction pattern shows the sample with pure TiO2, the only phase presence was brookite TiO2. When the Ag content added into the solution, the phase existed for the samples with TiO2doped 0.5g Ag and TiO2doped 1.0g Ag were anatase TiO2with no peak corresponds to Ag phase. The surface morphology of film was characterized by scanning electron microscopy (SEM). The films were annealed at 450 °C and it shows non-uniform films. The films have a large flaky and cracks film which was attributed to surface tension between the film and the air during the drying process. When the solution of sol was added with Ag content, it shows the porous structure with flaky-crack films. With the increasing of the Ag content from 0.5g to 1.0g, the structure is more porous and it is good for the photocatalytic activity. The UV-Vis spectra shows that the film exhibits a low absorbance which was due to the substrate is inhomogeneously covered by the flaky-crack films.


2008 ◽  
Vol 47-50 ◽  
pp. 1063-1066 ◽  
Author(s):  
Costel Birsan ◽  
Cristina Ghitulica ◽  
Ecaterina Andronescu ◽  
Cristina Ionita ◽  
Mihaela Birsan

The aim of the study was the synthesis and characterization of bioactive osteoinductive glasses, in the SiO2 – CaO – P2O5 system. In order to maintain the bioactive character of bioglasses, for SiO2 contents higher than 60%, the sol – gel method was used for preparation. On the obtained powders, thermal, grain size and X - ray diffraction analysis were performed. The X - ray diffraction emphasized the formation of phosphate phases, whose proportion decreases as the silica content is increased. Later, the powders were thermally treated at temperatures between 1000 and 14000C, the phase composition evolution being monitored through XRD analysis. On the powder suspensions in physiological serum, the evolution of pH was investigated, in order to establish the chemical stability. The behavior of the obtained powders in physiological medium was studied, by immersing samples in simulated body fluid and excerpted after different periods of time.


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