| Texto completo | |
| Autor(es): |
Cavalcante, L. S.
[1, 2]
;
Batista, F. M. C.
[3]
;
Almeida, M. A. P.
[4]
;
Rabelo, A. C.
[4]
;
Nogueira, I. C.
[4]
;
Batista, N. C.
[2]
;
Varela, J. A.
[1]
;
Santos, M. R. M. C.
[3]
;
Longo, E.
[4, 2]
;
Li, M. Siu
[5]
Número total de Autores: 10
|
| Afiliação do(s) autor(es): | [1] Univ Estadual Paulista, BR-14801907 Araraquara, SP - Brazil
[2] Univ Estadual Piaui, CCN, Dept Quim, BR-64002150 Teresina, PI - Brazil
[3] Univ Fed Piaui, LIMAV CCN Quim, BR-64049550 Teresina, PI - Brazil
[4] Univ Fed Sao Carlos, BR-13565905 Sao Carlos, SP - Brazil
[5] Univ Sao Paulo, IFSC, BR-13560970 Sao Carlos, SP - Brazil
Número total de Afiliações: 5
|
| Tipo de documento: | Artigo Científico |
| Fonte: | RSC ADVANCES; v. 2, n. 16, p. 6438-6454, 2012. |
| Citações Web of Science: | 54 |
| Resumo | |
Barium praseodymium tungstate (Ba1-xPr2x/3)WO4 crystals with (x = 0, 0.01, and 0.02) were prepared by the coprecipitation method. These crystals were structurally characterized by X-ray diffraction (XRD), Rietveld refinements, Fourier-transform Raman (FT-Raman) and Fourier-transform infrared (FT-IR) spectroscopies. The shape and size of these crystals were observed by field emission scanning electron microcopy (FE-SEM). Their optical properties were investigated by ultraviolet visible (UV-vis) absorption and photoluminescence (PL) measurements. Moreover, we have studied the photocatalytic (PC) activity of crystals for degradation of rhodamine B (RhB) dye. XRD patterns, Rietveld refinements data, FT-Raman and FT-IR spectroscopies indicate that all crystals exhibit a tetragonal structure without deleterious phases. FT-Raman spectra exhibited 13 Raman-active modes in a range from 50 to 1000 cm(-1), while FT-IR spectra have 8 infrared active modes in a range from 200 to 1050 cm(-1). FE-SEM images showed different shapes (bonbon-, spindle-, rice-and flake-like) as well as a reduction in the crystal size with an increase in Pr3+ ions. A possible growth process was proposed for these crystals. UV-vis absorption measurements revealed a decrease in optical band gap values with an increase of Pr3+ into the matrix. An intense green PL emission was noted for (Ba1-xPr2x/3)WO4 crystals (x = 0), while crystals with (x = 0.01 and 0.02) produced a reduction in the wide band PL emission and the narrow band PL emission which is related to f-f transitions from Pr3+ ions. High photocatalytic efficiency was verified for the bonbon-like BaWO4 crystals as a catalyst in the degradation of the RhB dye after 25 min under UV-light. Finally, we discuss possible mechanisms for PL and PC properties of these crystals. (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 |