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(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

Morphological and structural evolution from akaganeite to hematite of nanorods monitored by ex situ synchrotron X-ray powder diffraction

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Autor(es):
Xavier, Allan Moreira [1] ; Ferreira, Fabio Furlan [1] ; Souza, Flavio Leandro [1]
Número total de Autores: 3
Afiliação do(s) autor(es):
[1] Univ Fed ABC UFABC, Ctr Ciencias Nat & Humanas, BR-09210580 Santo Andre, SP - Brazil
Número total de Afiliações: 1
Tipo de documento: Artigo Científico
Fonte: RSC ADVANCES; v. 4, n. 34, p. 17753-17759, 2014.
Citações Web of Science: 21
Resumo

Hematite (alpha-Fe2O3) is one of the most abundant minerals in nature and a thermodynamically-stable phase of iron oxide. One-dimensional (1D) hematite nanostructures have attracted, due to their fundamental characteristics such as excellent chemical stability in aqueous environments and low cost, considerable interest for a series of technical applications (as sensors, catalysis, lithium ion batteries and solar energy production and storage). Our study describes the phase evolution of iron oxide nanorods, from beta-FeOOH to alpha-Fe2O3, with increasing temperatures of thermal treatment monitored by ex situ synchrotron X-ray powder diffraction data. These data used in conjunction with the Rietveld method allowed us to infer the phase concentration, elucidate the influence of temperature on the unit cell parameters and preferred growth orientation of the nanorods. Only the use of synchrotron radiation allowed us to precisely identify and quantify the presence of a minor Fe2O3 phase, which has never before been reported for those systems. Moreover, the formation of one-dimensional nanorods was accompanied by using scanning and transmission electron microscopies (SEM and TEM). At the highest temperatures of thermal treatments the hematite nanorods exhibited changes that varied from a quasi-perfect crystal up to polycrystalline rods (> 500 degrees C). These findings were used for discussing and explaining recent results using this kind of nanostructure synthesized under hydrothermal conditions. Changes in the preferred orientation of the crystal faces of the rods could be responsible for a low photocatalytic performance reported by this strategy. (AU)

Processo FAPESP: 08/10537-3 - Estudo de polimorfos de fármacos cristalinos através da difração de raios X por policristais e do método de Rietveld
Beneficiário:Fabio Furlan Ferreira
Linha de fomento: Auxílio à Pesquisa - Apoio a Jovens Pesquisadores
Processo FAPESP: 12/19926-8 - Nanoestruturas de óxidos metálicos aplicadas em dispositivos fotoeletroquímicos
Beneficiário:Flavio Leandro de Souza
Linha de fomento: Auxílio à Pesquisa - Regular
Processo FAPESP: 11/19924-2 - Estudo e desenvolvimento de novos materiais avançados: eletrônicos, magnéticos e nanoestruturados: uma abordagem interdisciplinar
Beneficiário:Carlos Rettori
Linha de fomento: Auxílio à Pesquisa - Temático