0000000000732806

AUTHOR

V. D. Araújo

showing 2 related works from this author

F-centre luminescence in nanocrystalline CeO2

2013

Nanocrystalline CeO2 powders were synthesized by two cost-effective methods: the self-propagating room temperature (SPRT) method and the precipitation method. Differently prepared samples exhibited different temperature-dependent photoluminescence (PL) in the ultraviolet and visible regions. The PL signals originated from different kinds of oxygen-deficient defect centres with or without trapped electrons (F0, F+ or F++ centres). The temperature-dependent PL spectra were measured using different excitation lines, below (457, 488 and 514?nm) or comparable (325?nm) to the ceria optical band gap energy, in order to investigate the positions of intragap localized defect states. Evidence for the…

Materials sciencePhotoluminescenceAcoustics and UltrasonicsBand gapPrecipitation (chemistry)Analytical chemistry02 engineering and technology010402 general chemistry021001 nanoscience & nanotechnologyCondensed Matter Physicsmedicine.disease_cause01 natural sciencesNanocrystalline material0104 chemical sciencesSurfaces Coatings and FilmsElectronic Optical and Magnetic Materialslaw.inventionlawmedicine0210 nano-technologyElectron paramagnetic resonanceLuminescenceUltravioletExcitationJournal of Physics D: Applied Physics
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Catalytic oxidation of n-hexane promoted by Ce1-xCuxO2 catalysts prepared by one-step polymeric precursor method

2013

Abstract Ceria-supported copper catalysts (Ce1−xCuxO2, with x (mol) = 0, 0.01, 0.03, 0.05 and 0.10) were prepared in one step through the polymeric precursor method. The textural properties of the catalysts were investigated by X-ray diffraction (XRD), Rietveld refinement, N2-physisorption (BET surface area), electron paramagnetic resonance (EPR), UV–visible diffuse reflectance and photoluminescence spectroscopies and temperature-programmed reduction (TPR). In a previous study ceria-supported copper catalysts were found to be efficient in the preferential oxidation of CO. In this study, we extended the catalytic application of Ce1−xCuxO2 systems to n-hexane oxidation and it was verified tha…

Materials scienceRietveld refinementInorganic chemistrychemistry.chemical_elementCondensed Matter PhysicsCopperlaw.inventionCatalysisHexanechemistry.chemical_compoundCatalytic oxidationchemistrylawGeneral Materials ScienceDiffuse reflectionDIFRAÇÃO POR RAIOS XElectron paramagnetic resonanceBET theory
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