SrTiO3 preparation through coprecipitation methods

Zorel, H. E.; Guinesi, Luciana Simionatto; Ribeiro, Clóvis Augusto; Crespi, Marisa Spirandeli

doi:10.1016/s0167-577x(99)00152-4

Cited by 11 publications

(6 citation statements)

References 9 publications

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“…The huge difference in chemical reactivity between Sr 2+ and Ti 3+ ions is an impediment to the preparation of Perovskite-type SrTiO 3 nanoparticles, as it may reduce drastically the homogeneity of the precursors [8,11]. As observed in the experiments, the hydrolysis and condensation rate of Ti 3+ alone in aqueous solution was rather fast, forming a gel within 1 min after the addition of PPO.…”

Section: Discussionmentioning

confidence: 98%

“…Usually, solution chemistry routes offer good control over the properties of the precursor and the final materials, allowing the large-scale synthesis of nanoparticles. However, the huge difference in chemical reactivity between Ti and Sr source precursors usually produces Sr-Ti oxide precursors with low homogeneity, when prepared by traditional methods such as coprecipitation [11]. This, results in the formation of impurity phases and in the increase of the particle size of the final product, due to the high temperature required to obtain the target phase.…”

Section: Introductionmentioning

confidence: 99%

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Controlled homogeneity of the precursor gel in the synthesis of SrTiO3 nanoparticles by an epoxide assisted sol–gel route

Cui

Zayat

Lévy

2007

Journal of Non-Crystalline Solids

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Section: Discussionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Controlled homogeneity of the precursor gel in the synthesis of SrTiO3 nanoparticles by an epoxide assisted sol–gel route

Cui

Zayat

Lévy

2007

Journal of Non-Crystalline Solids

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“…(4)(5)(6) However, these characteristics are dependent on particle size, morphology, crystalline structural defects, and surface properties, which are defined by the conditions used in the synthesis method. The typical methods used to prepare either BSTO or STO involve high temperature via solid-state reaction, (7) combustion,(4) molten salt,(8-10) and pyrolysis; (11) however, recently, low-temperature soft chemical methods (1)(2)(3)12) such as sol-gel, (13,14) chemical coprecipitation, (15) and liquid-solid reactions, are being used, because of their simplicity, low cost, and environmentally friendly nature.…”

Section: Introductionmentioning

confidence: 99%

“…The STO is an indirect band gap semiconductor with a band gap of 3.4 eV and has high thermal and chemical stability and a low thermal expansion coefficient, which are attractive features for a broad range of applications, including catalysts, , electronics, and optoelectronics. − However, these characteristics are dependent on particle size, morphology, crystalline structural defects, and surface properties, which are defined by the conditions used in the synthesis method. The typical methods used to prepare either BSTO or STO involve high temperature via solid-state reaction, combustion, molten salt, − and pyrolysis; however, recently, low-temperature soft chemical methods − , such as sol–gel, , chemical coprecipitation, and liquid–solid reactions, are being used, because of their simplicity, low cost, and environmentally friendly nature.…”

Section: Introductionmentioning

confidence: 99%

Facile Synthesis of Perovskite-Structured Powders Using Barite–Celestite Ore under Hydrothermal Alkaline Conditions

Rendón-Ángeles¹,

Matamoros-Veloza

Veloza

et al. 2017

Ind. Eng. Chem. Res.

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Barite-celestite (BC) crystals were treated in highly concentrated alkaline hydrothermal fluid (5 M KOH) coexisting with a Ti(OH)4•4.5H2O gel to produce SrTiO3 particles between 150 and 250 °C for several intervals between 6 h and 96 h. The BC transformation was initiated at a lower temperature (150 °C) and the total precursors consumption was completed at 250 °C for 96 h, resulting only in the crystallization of SrTiO3 particles. Different temperatures of reaction (≤200 °C) lead to variations in morphology and particle size of the SrTiO 3. The crystal growth of faceted cubic agglomerates was achieved at 250 °C, and it is provoked by the Oswald ripening mechanism. The release of barium to the hydrothermal fluid from the precursor occurred simultaneously with the transformation process. A low value of activation energy required for the single-step transformation of the BC plates into SrTiO3 particles was observed (26.33 kJ mol-1), under static hydrothermal conditions.

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“…Avaliação destes complexos quanto à estrutura, estequiometria e comportamento térmico encontram-se relatados [3][4][5][6][7][8][9] . A influência de substituintes, como os halogêneos, grupos carboxila e grupos acetila, na estrutura do quelante, conduz à variações nas condições de preparação e no comportamento térmico dos complexos sóli-dos, devido à modificações na distribuição eletrônica nos anéis do quelante 10,11 , conduzindo à mudanças de estabilidade térmi-ca e composição dos resíduos [12][13][14] .…”

Section: Introductionunclassified

Comportamento térmico do 8-quinolinol e seus nitro-derivados

Zorel¹,

Costalonga²,

Crespi³

et al. 2001

Quím. Nova

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Recebido em 31/5/00; aceito em 15/3/01 THERMAL BEHAVIOR OF THE 8-QUINOLINOL AND THEIR NITRO-DERIVATIVES. The compounds 5-nitro-8-quinolinol and 5,7-dinitro-8-quinolinol were obtained by nitration of the chelant 8-quinolinol. The compounds were characterized through EA, MNR, XRD, IR, TG, DTA and DSC. It was verified through thermal analysis that the compounds show consecutive processes of sublimation, fusion and vaporization. During the vaporization process, partial thermal decomposition was observed, with formation of carbonaceous residues. Considering a slower heating rate, the sublimation is the prevalent process to the nitro-derivatives while the vaporization is the main process to 8-quinolinol. The thermal stability follows the decreasing order from 5,7-dinitro-8-quinolinol to 5-nitro-8-quinolinol to 8-quinolinol.Keywords: thermal behavior; 8-quinolinol; nitro-derivatives. ArtigoQuim. Nova, Vol. 24, No. 5, 599-603, 2001. INTRODUÇÃOO quelante 8-quinolinol é objeto de estudos em diferentes sistemas, como na separação e quantificação de metais, onde a formação dos complexos metálicos sólidos é altamente dependente do pH e meio de precipitação 1,2 . Avaliação destes complexos quanto à estrutura, estequiometria e comportamento térmico encontram-se relatados 3-9 . A influência de substituintes, como os halogêneos, grupos carboxila e grupos acetila, na estrutura do quelante, conduz à variações nas condições de preparação e no comportamento térmico dos complexos sóli-dos, devido à modificações na distribuição eletrônica nos anéis do quelante 10,11 , conduzindo à mudanças de estabilidade térmi-ca e composição dos resíduos [12][13][14] . Os estudos do 8-quinolinol e seus derivados em sistemas biológicos ocorrem em função de interações com estruturas presentes no organismo [15][16][17][18][19][20][21][22][23] . A. Y. Shen et al. 24 investigaram a utilização do 8-quinolinol, como bases de Mannich, no combate ao câncer em células humanas enquanto que M. P. Zawistoski 25 estudou a utilização de 5-nitro-8-quinolinol como um grupo de proteção para enxofre na síntese de tioquinolinas 5-carboxi-8-substituídas, utilizadas como intermediários para a síntese de inibidores H + ,K + -ATPase. A adição do grupo NO 2 nas posições 5 e/ou 7 na estrutura do 8-quinolinol, resulta em produtos utilizados como fungicida e bactericida 26,27 . M. A. Zayed et al 28 investigaram o comportamento térmico do quelante 5,7-dinitro-8-quinolinol e seu complexo com urânio por espectrometria de massa e análise térmica diferencial apresentando resultados, em relação ao quelante, diferentes daqueles reportados na literatura 29 e por nós obtidos. Devido às diferentes aplicações que o quelante 8-quinolinol e seus nitro-derivados podem apresentar, faz-se necessário uma correta caracterização destes compostos bem como determinar a influência da temperatura em seu comportamento. Neste trabalho, a preparação e caracterização dos nitro-derivados do 8-quinolinol são apresentadas, juntamente com um estudo comparativo destes compostos quanto ao comportamento térmic...

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SrTiO3 preparation through coprecipitation methods

Cited by 11 publications

References 9 publications

Controlled homogeneity of the precursor gel in the synthesis of SrTiO3 nanoparticles by an epoxide assisted sol–gel route

Controlled homogeneity of the precursor gel in the synthesis of SrTiO3 nanoparticles by an epoxide assisted sol–gel route

Facile Synthesis of Perovskite-Structured Powders Using Barite–Celestite Ore under Hydrothermal Alkaline Conditions

Comportamento térmico do 8-quinolinol e seus nitro-derivados

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