Browsing by Author "Libanori, Rafael"

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    Preparation, characterization and catalytic properties of titanium oxide nanoparticles coated with aluminum oxide.
    (2011) Carreño, Neftalí Lenin Villarreal; Leite, Edson Roberto; Libanori, Rafael; Probst, Luiz Fernando Dias; Fajardo, Humberto Vieira
    In the present study, TiO2 nanopowder was partially coated with Al2O3 precursors generated by a polymeric precursor method in aqueous solution. The system of nanocoated particles formed an ultra thin structure on the TiO2 nanoparticle surfaces, where the particle is the core and the nanocoating (additive) is the shell. The nanocoating process led to the obtainment of nanoparticles with important surface characteristics and catalytic behavior in the bioethanol dehydration reaction, with improved activity and particular selectivity in comparison to their non-coated analogs. Ethylene production was disfavored and selectivity toward acetaldehyde, hydrogen and ethane increased with increasing Al2O3 content in the catalysts. It is important to highlight that the TiO2–Al2O3 catalysts presented satisfactory values of selectivity toward hydrogen, in spite of the deactivation observed during the period of the test.
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    Synthesis, characterization and catalytic properties of nanocrystaline Y2O3-coated TiO2 in the ethanol dehydration reaction.
    (2012) Fajardo, Humberto Vieira; Longo, Elson; Leite, Edson Roberto; Libanori, Rafael
    In the present study, TiO2 nanopowder was partially coated with Y2O3 precursors generated by a sol-gel modified route. The system of nanocoated particles formed an ultra thin structure on the TiO2 surfaces. The modified nanoparticles were characterized by high resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD) analysis, Zeta potential and surface area through N2 fisisorption measurements. Bioethanol dehydration was used as a probe reaction to investigate the modifications on the nanoparticles surface. The process led to the obtainment of nanoparticles with important surface characteristics and catalytic behavior in the bioethanol dehydration reaction, with improved activity and particular selectivity in comparison to their non-coated analogs. The ethylene production was disfavored and selectivity toward acetaldehyde, hydrogen and ethane increased over modified nanoparticles.