Preparation, characterization and catalytic application of Barium molybdate (BaMoO4) and Barium tungstate (BaWO4) in the gas-phase oxidation of toluene.
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2017
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Abstract
Barium molybdate and Barium tungstate are important materials due their photoluminescent properties and
they also have catalysis and photocatalysis applications. In this work, powders of these compounds were
prepared by microwave-assisted hydrothermal (MAH) method and polymeric precursor method (PPM) and
their structural and optical properties were studied. Furthermore, these materials were employed as solid
catalysts towards gas phase toluene oxidation reactions. X-ray diffraction confirms the purity of materials at
both preparation methods and reveals a preferential growth when the powders are prepared by MAH due
polymeric agents and processing using microwave, which was confirmed by Field emission scanning electron
microscopy. Photoluminesce emission was attributed to the charge-transfer transitions within the [WO4]2- and
[MoO4]2- complexes. The H2 Temperature-Programmed Reduction (H2-TPR), O2-chemisorption and extended
X-ray absorption fine structure (EXAFS) results indicated that BaWO4 samples, compared with BaMoO4
samples, have higher oxygen mobility and oxygen vacancies that appear as key factors for the achievement of
better catalytic performances.
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Keywords
Microwave-assisted hydrothermal, Polymeric precursor
Citation
ALENCAR, L.D. da S. et al. Preparation, characterization and catalytic application of Barium molybdate (BaMoO4) and Barium tungstate (BaWO4) in the gas-phase oxidation of toluene. Ceramics International, v. 43, n. 5, p. 4462-4469, abr. 2017. Disponível em: <http://www.sciencedirect.com/science/article/pii/S0272884216323641>. Acesso em: 15 set. 2017.