Please use this identifier to cite or link to this item: http://www.repositorio.ufop.br/handle/123456789/11200
Title: Effect of different synthesis methods on the textural properties of calcium tungstate (CaWO4 ) and Its catalytic properties in the toluene oxidation.
Authors: Alencar, Lorena Dariane da Silva
Lima, Naiara Arantes
Mesquita, Alexandre
Probst, Luiz Fernando Dias
Batalha, Daniel Carreira
Rosmaninho, Marcelo Gonçalves
Fajardo, Humberto Vieira
Bernardi, Maria Inês Basso
Keywords: X-ray absorption near edge spectroscopy
Extended X-ray absorption fine structure
Issue Date: 2018
Citation: ALENCAR, L. D. da S. et al. Effect of different synthesis methods on the textural properties of calcium tungstate (CaWO4 ) and Its catalytic properties in the toluene oxidation. Materials Research, v. 21, n. 3, p. e20170961, abr. 2018. Disponível em: <http://www.scielo.br/scielo.php?pid=S1516-14392018005022107&script=sci_abstract>. Acesso em: 7 mar. 2019.
Abstract: Calcium tungstate (CaWO4) crystals were prepared by microwave-assisted hydrothermal (MAH) and polymeric precursor methods (PPM). These crystals were structurally characterized by X-ray diffraction (XRD), N2 adsorption, X-ray absorption near edge spectroscopy (XANES) and extended X-ray absorption fine structure (EXAFS) measurements. The morphology and size of these crystals were observed by field emission scanning electron microscopy (FE-SEM). Their optical properties were investigated by ultraviolet visible (UV-Vis) absorption and photoluminescence (PL) measurements. Moreover, these materials were employed as catalysts towards gas phase toluene oxidation reaction. XRD indicates the purity of materials for both preparation methods and MAH process produced crystalline powders synthesized at lower temperatures and shorter processing time compared to the ones prepared by PPM. FE-SEM images showed particles with rounded morphology and particles in clusters dumbbells-like shaped. PL spectra exhibit a broad band covering the visible electromagnetic spectrum in the range of 360 to 750 nm. XANES and EXAFS results show that preparation method does not introduce high disorders into the structure, however the H2-TPR results indicated that the catalyst reducibility is affected by the preparation method of the samples.
URI: http://www.repositorio.ufop.br/handle/123456789/11200
metadata.dc.identifier.doi: http://dx.doi.org/10.1590/1980-5373-mr-2017-0961
ISSN: 1516-1439
metadata.dc.rights.license: O periódico Materials Research dá permissão ao RI/UFOP para depositar uma cópia eletrônica dos artigos publicados por esse periódico em que ao menos um dos autores é aluno ou professor da UFOP. Contato via email em 25 out. 2013.
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