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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Structural refinement, growth process, photoluminescence and photocatalytic properties of (Ba1-xPr2x/3)WO4 crystals synthesized by the coprecipitation method

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Author(s):
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]
Total Authors: 10
Affiliation:
[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
Total Affiliations: 5
Document type: Journal article
Source: RSC ADVANCES; v. 2, n. 16, p. 6438-6454, 2012.
Web of Science Citations: 54
Abstract

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)