Effect of glycine–starch mixing ratio on the structural characteristics of MgAl2O4 nano-particles synthesized by sol–gel combustion

Motevalian, Arash; Salem, Shiva

doi:10.1016/j.partic.2015.03.005

Cited by 18 publications

(14 citation statements)

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“…18 For this reason, the sol-gel method has been widely used modulating these properties. 6,[18][19][20][21][22][23][24][25][26][27][28] The sol-gel method allows a larger surface area for the obtained solids, in our study the LiCoO 2 powder. In addition, this technique also enables a smaller Li-ion diffusion length due to the reduced LiCoO 2 Freitas et al 2255 Vol.…”

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confidence: 99%

Synthesis and Characterization of LiCoO2 from Different Precursors by Sol‑Gel Method

Freitas

Siqueira

Costa

et al. 2017

J. Braz. Chem. Soc.

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Lithium cobalt oxide, LiCoO 2 , widely used as cathode in lithium ion batteries was synthesized and their structural and electronic properties investigated. The crystalline powders were prepared by the sol-gel method with four complexing agents: citric acid, glycine, starch and gelatin. These syntheses were compared with the blank test (without complexing agent). The X-ray diffraction and vibrational spectroscopy allowed the identification of the rhombohedral phase LiCoO 2 ( ) as the only or principal crystalline component in all samples. A small fraction of a second phase of cubic spinel Co 3 O 4 was observed in the samples of starch, gelatin and the blank test. The Rietveld refinements showed small structural variations, indicating reduced influence of the complexing agents on the synthesis. The theoretical HOMO-LUMO (highest occupied molecular orbital-lowest unoccupied molecular orbital) gap values are in agreement to those estimated by diffuse reflectance spectroscopy (DRS). The scanning electron microscopy (SEM) showed morphological pattern regardless of the complexing agent used, showing an alternative method.Keywords: LiCoO 2 , sol-gel method, XRD, Rietveld refinement, lithium ion batteries, DFT IntroductionLithium cobalt oxide, LiCoO 2 , has been the focus of many studies regarding their structural and electronic properties. [1][2][3][4][5][6][7][8] This system has interesting electrochemical features that allows a wide use as cathodes of lithium ion batteries. 2,4 The investigation of the structural aspects of the material is a crucial issue to better understand the electrochemical properties of the LiCoO 2 compound. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] For example, the nature of the crystal, its size and shape, are directly related with its electrochemical characteristics. 2 The LiCoO 2 synthesized at low temperatures (LT), below 500 °C, presents a cubic spinel structure ( ), while the synthesis at high temperatures (HT) (above 500 °C), generates the rhombohedral structure with stratified layers ( ). Therefore, several authors usually classify these structures as LT-LiCoO 2 and HT-LiCoO 2 , respectively . 1,2,7,8,[18][19][20][21][22][23][24] The rhombohedral phase is characterized by a structure with alternating layers of cobalt and lithium cations intercalated with oxygen anions. 22 The lithium and cobalt(III) ions are arranged in intercalated layers (Figure 1a). The cobalt(III) ion is located at the octahedral sites, forming a strong bond with the neighboring oxygen anion to constitute the Co−O layers (Figure 1b). Finally, the lithium layers are intercalated between the CoO 2 plans. 1,3,4 The octahedral sites of these layers are occupied by lithium and cobalt(III) ions alternately that forms a sequential stacking with oxygen ion layers in a close packing of the ABCABC type ( Figure 1c). 4,5 This specific stacking arrangement leads to an environment equivalent for all ions, allowing the maximum charge delocalization and the minimal system energy. 1,3,4 The degree of crystal orde...

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confidence: 99%

Synthesis and Characterization of LiCoO2 from Different Precursors by Sol‑Gel Method

Freitas

Siqueira

Costa

et al. 2017

J. Braz. Chem. Soc.

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“…which is observable in spectrum of the sample obtained after calcination may be attributed to the vibration of NO 3 groups [19].Hence, the observed and Ag/MgAl 2 O 4 sample at pH=6are shown in Fig. 4a-4f.…”

Section: Preparation Of Catalystsmentioning

confidence: 79%

Ag/MgAl<sub>2</sub>O<sub>4</sub>nanoparticles Prepared by a Modified Hydrothermal for Photocatalytic Degradation of Methylene Blue

Zhu

Zhang

2017

Preprint

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“…Among organic fuels, glycine is an amino acid that facilitates the formation of metal ion complex in the solution owing to its carboxylic acid and amino groups at opposite ends of the molecule [22]. BFO has been synthesized by glycine fuel thru microwave-assisted solution combustion with some portion of impurity phases such as Bi 2 Fe 4 O 9 and Bi 24 Fe 2 O 39 [23].…”

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confidence: 99%

Photocatalytic properties of BiFeO 3 powders synthesized by mixture of CTAB and Glycine

Asefi

Hasheminiasari

Masoudpanah

2020

Preprint

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Highly pure BiFeO3 (BFO) powders were prepared by solution combustion synthesis method using cetyltrimethylammonium bromide (CTAB) and glycine as fuels at various fuel to oxidant (φ) ratios.Microstructural characteristics, morphology, optical properties, and thermal analysis were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS), and differential thermal/thermogravimetry (DTA/TGA), respectively. The combusted powders prepared at different fuel content contained some impurity phases such as Bi24Fe2O39 and Bi2Fe4O9. During the calcination of BFO powders at 600 °C for 1 hour, nearly pure BFO phase was produced. About 80% of methylene blue dye was photodegraded by combusted powders at φ=2 through 90 minutes of visible light irradiation.Developing simple, environmentally safe, and energy-efficient methods are of great interest to synthesize a pure BFO powder. Solution combustion synthesis (SCS) is a simple, relatively cheap, and fast chemical process to produce various nanomaterials [21]. A self-propagating exothermic reaction takes place between the mixture of metal nitrates and different organic fuels (e.g., glycine, citric acid, urea, etc.), releasing an enormous amount of gaseous products [20].Among organic fuels, glycine is an amino acid that facilitates the formation of metal ion complex in the solution owing to its carboxylic acid and amino groups at opposite ends of the molecule [22]. BFO has been synthesized by glycine fuel thru microwave-assisted solution combustion with some portion of impurity phases such as Bi 2 Fe 4 O 9 and Bi 24 Fe 2 O 39 [23]. Likewise, Cetyltrimethylammonium bromide (CTAB) is a cationic surfactant with high decomposition temperature that is extensively used to control particle shapes, size, and microstructure via minimizing the precursor's surface tension [24].Nevertheless, combining different fuels might be more effectual than that of individual fuels via improved control over the reaction temperature, the type, and the amount of gaseous products released. Therefore, in this project, glycine and CTAB were mixed in the uni-molar ratio to synthesize nearly pure and single-phase BFO. Experimental Procedure Synthesis RouteAnalytical grades Fe(NO 3 ) 3 .9H 2 O, Bi(NO 3 ) 2 .5H 2 O, CTAB [(C 16 H 33 )N(CH 3 ) 3 ]Br (> 99%), glycine (C 2 H 5 NO 2 ), were purchased from Merk Co. without any further purification. Whereby HNO 3 (68 wt %) was added to dissolve bismuth nitrate.The required amount of Bi(NO 3 ).5H 2 O and Fe(NO 3 ).9H 2 O, cetyltrimethylammonium bromide ([(C 16 H 33 )N(CH 3 ) 3 ]Br), and glycine (C 2 H 5 NO 2 ) were prepared by dissolving 15 mL of 3 mol L -1 of HNO 3 in various fuel to oxidant ratios of (φ = 0.5, 0.75, 1 and 2). H 2 O, CO 2 , Br 2 , and N 2 are assumed to be the gaseous products of combustion reaction where the type of gaseous products and adiabatic temperature are controlled by the fuel to oxidant ratio (φ).

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Effect of glycine–starch mixing ratio on the structural characteristics of MgAl2O4 nano-particles synthesized by sol–gel combustion

Cited by 18 publications

References 20 publications

Synthesis and Characterization of LiCoO2 from Different Precursors by Sol‑Gel Method

Synthesis and Characterization of LiCoO2 from Different Precursors by Sol‑Gel Method

Ag/MgAl<sub>2</sub>O<sub>4</sub>nanoparticles Prepared by a Modified Hydrothermal for Photocatalytic Degradation of Methylene Blue

Photocatalytic properties of BiFeO 3 powders synthesized by mixture of CTAB and Glycine

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