| Texto completo | |
| Autor(es): |
Cavalcante, L. S.
[1, 2]
;
Almeida, M. A. P.
[3]
;
Avansi, Jr., W.
[2]
;
Tranquilin, R. L.
[3]
;
Longo, E.
[3, 2]
;
Batista, N. C.
[1]
;
Mastelaro, V. R.
[4]
;
Siu Li, M.
[4]
Número total de Autores: 8
|
| Afiliação do(s) autor(es): | [1] UESPI CCN, Dept Quim, BR-64002150 Teresina, PI - Brazil
[2] Univ Estadual Paulista, BR-14801907 Sao Paulo - Brazil
[3] Univ Fed Sao Carlos, BR-13565905 Sao Paulo - Brazil
[4] Univ Sao Paulo, IFSC, BR-13560970 Sao Paulo - Brazil
Número total de Afiliações: 4
|
| Tipo de documento: | Artigo Científico |
| Fonte: | Inorganic Chemistry; v. 51, n. 20, p. 10675-10687, OCT 15 2012. |
| Citações Web of Science: | 97 |
| Resumo | |
In this paper, we report our initial research to obtain hexagonal rod-like elongated silver tungstate (alpha-Ag2WO4) microcrystals by different methods {[}sonochemistry (SC), coprecipitation (CP), and conventional hydrothermal (CH)] and to study their cluster coordination and optical properties. These microcrystals were structurally characterized by X-ray diffraction (XRD), Rietveld refinements, Fourier transform infrared (FT-IR), X-ray absorption near-edge structure (XANES), and extended X-ray absorption fine structure (EXAFS) spectroscopies. The shape and average size of these alpha-Ag2WO4 microcrystals were observed by field-emission scanning electron microscopy (FE-SEM). The optical properties of these microcrystals were investigated by ultraviolet-visible (UV-vis) spectroscopy and photoluminescence (PL) measurements. XRD patterns and Rietveld refinement data confirmed that alpha-Ag2WO4 microcrystals have an orthorhombic structure. FT-IR spectra exhibited four IR-active modes in a range from 250 to 1000 cm(-1). XANES spectra at the W L-3-edge showed distorted octahedral {[}WO6] clusters in the lattice, while EXAFS analyses confirmed that W atoms are coordinated by six O atoms. FE-SEM images suggest that the alpha-Ag2WO4 microcrystals grow by aggregation and the Ostwald ripening process. PL properties of alpha-Ag2WO4 microcrystals decrease with an increase in the optical band-gap values (3.19-3.23 eV). Finally, we observed that large hexagonal rod-like alpha-Ag2WO4 microcrystals prepared by the SC method exhibited a major PL emission intensity relative to alpha-Ag2WO4 microcrystals prepared by the CP and CH methods. (AU) | |
| Processo FAPESP: | 09/53189-8 - Propriedades fotoluminescentes e fotocataliticas dos tungstatos de ferro e manganes |
| Beneficiário: | Marcio Aurélio Pinheiro Almeida |
| Modalidade de apoio: | Bolsas no Brasil - Doutorado |