Navegando por Autor "Araújo, Vinícius Dantas de"

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    Microwave hydrothermal synthesis, characterisation, and catalytic performance of Zn1−xMnxO in cellulose conversion.
    (2014) Bernardi, Maria Inês Basso; Araújo, Vinícius Dantas de; Ribeiro, Caue; Avansi Junior, Waldir; Longo, Elson; Albuquerque, Nilson José Araujo de; Meneghetti, Simoni Margareti Plentz; Almeida, Rusiene Monteiro de; Fajardo, Humberto Vieira
    Wurtzite-type Zn1−xMnxO (x = 0, 0.03, 0.05, 0.07) nanostructures were successfully synthesised using a simple microwave-assisted hydrothermal route and their catalytic properties were investigated in the cellulose conversion. The morphology of the nanocatalysts is dopant-dependent. Pure ZnO presented multi-plate morphology with a flower-like shape of nanometric sizes, while the Zn0.97Mn0.03O sample is formed by nanoplates with the presence of spherical nanoparticles; the Zn0.95Mn0.05O and Zn0.93Mn0.07O samples are mainly formed by nanorods with the presence of a small quantity of spherical nanoparticles. The catalyst without Mn did not show any catalytic activity in the cellulose conversion. The Mn doping promoted an increase in the density of weak acid sites which, according to the catalytic results, favoured promotion of the reaction
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    Preparation, structural characterization and catalytic properties of Co/CeO2 catalysts for the steam reforming of ethanol and hydrogen production.
    (2012) Lovón, Adriana Siviero Pagani; Quintana, Juan José Lovón; Almerindo, Gizelle Inácio; Valença, Gustavo Paim; Bernardi, Maria Inês Basso; Araújo, Vinícius Dantas de; Rodrigues, Thenner Silva; Robles Azocar, Patrícia Alejandra; Fajardo, Humberto Vieira
    In this paper, Co/CeO2 catalysts, with different cobalt contents were prepared by the polymeric precursor method and were evaluated for the steam reforming of ethanol. The catalysts were characterized by N2 physisorption (BET method), X-ray diffraction (XRD), UVevisible diffuse reflectance, temperature programmed reduction analysis (TPR) and field emission scanning electron microscopy (FEG-SEM). It was observed that the catalytic behavior could be influenced by the experimental conditions and the nature of the catalyst employed. Physicalechemical characterizations revealed that the cobalt content of the catalyst influences the metal-support interaction which results in distinct catalyst performances. The catalyst with the highest cobalt content showed the best performance among the catalysts tested, exhibiting complete ethanol conversion, hydrogen selectivity close to 66% and good stability at a reaction temperature of 600 _C.