Growth mechanism and photocatalytic properties of SrWO4 microcrystals synthesized by injection of ions into a hot aqueous solution
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2013-01-01
Autores
Cavalcante, L. S. [UNESP]
Sczancoski, J. C. [UNESP]
Batista, N. C.
Longo, Elson [UNESP]
Varela, José Arana [UNESP]
Orlandi, Marcelo Ornaghi [UNESP]
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Resumo
This paper reports our initial research to obtain SrWO4 microcrystals by the injection of ions into a hot aqueous solution and their photocatalytic (PC) properties. These microcrystals were structurally characterized by X-ray diffraction (XRD), Rietveld refinements and Fourier transform (FT)-Raman spectroscopy. The shape and average size of these SrWO 4 microcrystals were observed by field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). In addition, we have investigated the PC activity of microcrystals for the degradation of rhodamine B (RhB) and rhodamine 6G (Rh6G) dyes. XRD patterns, Rietveld refinement data and FT-Raman spectroscopy confirmed that SrWO4 microcrystals have a scheelite-type tetragonal structure without deleterious phases. FT-Raman spectra exhibited 12 Raman-active modes in a range from 50 to 1000 cm-1. FE-SEM and TEM images suggested that the SrWO4 microcrystals (rice-like - 95%; star-, flower-, and urchin-like - 5%) were formed by means of primary/secondary nucleation events and self-assembly processes. Based on these FE-SEM/TEM images, a crystal growth mechanism was proposed and discussed in details in this work. Finally, a good PC activity was first discovered of the SrWO4 microcrystals for the degradation of RhB after 80 min and Rh6G after 50 min dyes under ultraviolet-light, respectively. © 2012 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder.
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Palavras-chave
Hot-injection, Photocatalysis, Rhodamine, Rietveld refinement, SrWO4, Average size, Crystal growth mechanism, Field emission scanning electron microscopy, FT- Raman spectroscopy, FT-Raman spectrum, Growth mechanisms, Photo-catalytic, Photocatalytic property, Raman active modes, Rhodamine 6G, Rhodamine B, Self assembly process, TEM images, Tetragonal structure, Transmission electron microscopy tem, Urchin-like, XRD patterns, Crystal growth, Field emission microscopes, Raman spectroscopy, Solutions, Transmission electron microscopy, Tungstate minerals, X ray diffraction, Microcrystals
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Advanced Powder Technology, v. 24, n. 1, p. 344-353, 2013.