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

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]

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

• 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