Browsing by Author "Batalha, Daniel Carreira"

Now showing 1 - 9 of 9
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    Application of Al2O3/AlNbO4 in the oxidation of aniline to azoxybenzene.
    (2019) Batalha, Daniel Carreira; Luz, Sulusmon Cesar; Taylor, Jason Guy; Fajardo, Humberto Vieira; Noremberg, Bruno S.; Cherubin, Igor José da Silva; Silva, Ricardo Marques e; Gonçalves, Margarete Regina Freitas; Bergmann, Carlos Pérez; Valentini, Antoninho; Carreño, Neftalí Lenin Villarreal
    Al2O3/AlNbO4 powder was fabricated by a facile high-energy milling process. The precursor materials, Al2O3 and Nb2O5, are readily available and have very attractive properties. Moreover, the catalytic activity of the sample in the liquid phase oxidation of aniline (OA) in the presence of hydrogen peroxide as oxidant was evaluated. The catalyst was found to be highly efficient and selective in the oxidation of aniline to azoxybenzene under mild conditions. When mixed with 28% AlNbO4 the alumina-based catalyst achieved high conversion and selectivity and very similar to the pure Nb2O5.
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    Effect of different synthesis methods on the textural properties of calcium tungstate (CaWO4 ) and Its catalytic properties in the toluene oxidation.
    (2018) 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
    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.
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    Influence of Nb2O5 grown on SrTiO3 nanoseeds in the catalytic oxidation of thioanisole.
    (2022) Riemke, Fábio Calcagno; Ücker, Cátia Liane; Carreño, Neftalí Lenin Villarreal; Cava, Sergio da Silva; Teixeira, Moisés Paulo; Fajardo, Humberto Vieira; Taylor, Jason Guy; Silva, Marcio José da; Batalha, Daniel Carreira; Ratmann, Cristiane Wienke Raubach
    There is a growing interest on the reach for new environmentally friendly catalysts especially solid metal oxides. The functional properties of SrTiO3 (STO) and its combination with other materials seem promising to yield catalytic reactions. In this sense, niobium oxides, particularly its most stable form Nb2O5, have showing a stunning compatibility with SrTiO3 arrays producing applicable compounds for high yield catalytic benchmarks. Here we investigate the yield of SrTiO3 and the activity of SrTiO3/Nb2O5 catalytic system in the oxidation process of thioanisole. This catalyst was synthesized through microwave assisted hydrothermal process in which Nb2O5 react with SrTiO3 nanoseeds in solution. The SrTiO3 nanoseeds seem to have induced a long-range order monoclinic array for the Nb2O5 stoichiometry for a certain period after which a disordered nanocrystalline phase for Nb2O5 was formed. Although this Nb2O5 growth on SrTiO3 arrays has already been shown in the literature, it differs from the results expected for a Nb2O5 synthesis using the MAH method, which will only produce nanocrystalline matrices at the temperature of 130 ◦C in a 15-min synthesis. The SrTiO3/Nb2O5 catalyst demonstrated to be highly efficient in thioanisole oxidation with hydrogen peroxide.
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    Low temperature liquid phase catalytic oxidation of aniline promoted by niobium pentoxide micro and nanoparticles.
    (2017) Ventura, Wellington Martins; Batalha, Daniel Carreira; Fajardo, Humberto Vieira; Taylor, Jason Guy; Marins, Natália Hadler; Noremberg, Bruno S.; Tański, Tomasz; Carreño, Neftalí Lenin Villarreal
    A microwave-assisted hydrothermal method was employed to synthesis Nb2O5 (niobium pentoxide) nanoparticles and the effects of synthesis conditions on the physical-chemical properties were evaluated. The catalytic activity of the prepared samples in the liquid phase oxidation of aniline with aqueous hydrogen peroxide as oxidizing agent was also studied. The nanoparticles showed hexagonal structure and rounded shape covered by nanoneedles. The results evidenced high catalytic activity with total conversion of aniline at ambient condition. Aniline conversion and product selectivities depended on the experimental parameters, particularly the oxidizing agent concentration, the nature of the solvent, type of the catalyst and reaction time.
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    Oxidação da anilina em fase líquida para obtenção de compostos com alto valor agregado promovida por óxidos de cério, nióbio e alumínio.
    (2017) Batalha, Daniel Carreira; Fajardo, Humberto Vieira; Fajardo, Humberto Vieira; Bellido, Jorge David Alguiar; Rosmaninho, Marcelo Gonçalves
    O desenvolvimento de novos catalisadores faz parte do cotidiano dos pesquisadores da comunidade catalítica. Este trabalho traz uma breve abordagem sobre a preparação de catalisadores heterogêneos a base de óxido de cério, produzidos pelo método dos precursores poliméricos (método Pechini) e síntese hidrotérmica, e catalisadores mistos de óxido de alumínio e óxido de nióbio, preparados pelo método de mistura mecânica, para utilização na oxidação da anilina em fase líquida, para obtenção de produtos com elevado valor agregado. Os resultados obtidos através das caracterizações físico-químicas e dos ensaios catalíticos mostraram que as metodologias adotadas para a preparação dos catalisadores proporcionaram a obtenção de materiais com interessantes propriedades texturais e catalíticas, comparativamente aos materiais análogos disponíveis comercialmente. Os catalisadores se mostraram ativos frente ao processo de oxidação da anilina em fase líquida, usando o peróxido de hidrogênio como agente oxidante. Os resultados evidenciaram alta atividade dos catalisadores preparados, em alguns casos com conversão total da anilina em condições reacionais brandas (temperatura e pressão ambiente). A atividade e a seletividade dos catalisadores variaram em função da natureza do catalisador, quantidade de agente oxidante, tipo de solvente, temperatura, massa de catalisador e tempo de reação empregados. No caso dos catalisadores a base de céria, o comportamento catalítico pareceu ser afetado principalmente pela mobilidade das espécies de oxigênio superficiais. Já para os catalisadores mistos (nióbia-alumina), conversão e seletividade pareceram estar relacionadas com o grau de hidroxilação na superfície dos óxidos, baseado na seguinte ordem: Nb2O5 > AlNbO4 > Al2O3. Palavras-chave: Catálise heterogênea; Oxidação da anilina; Óxido de cério; Niobato de alumínio.
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    Oxidation of terpenic alcohols with hydrogen peroxide promoted by Nb2O5 obtained by microwave-assisted hydrothermal method.
    (2020) Batalha, Daniel Carreira; Marins, Natália Hadler; Silva, Ricardo Marques e; Carreño, Neftalí Lenin Villarreal; Fajardo, Humberto Vieira; Silva, Márcio José da
    The present work describes the synthesis of niobium oxides by microwave-assisted hydrothermal method and their evaluation as a solid catalyst in oxidation reactions of terpenic alcohols with hydrogen peroxide. Effects of main parameters of synthesis were assessed and all the prepared catalysts were characterized by physical adsorption/ desorption analyses of nitrogen, infrared and Raman spectroscopies, scanning electron microscopy and powder X-rays diffraction analyses. The strength and number of acidic sites of the catalysts were determined by potentiometric titration. Morphological and structural characterization corroborate with the activity and selectivity achieved by the niobium oxides. The reusability of the catalyst was evaluated. The impacts of main reaction variables such as temperature, catalyst, and oxidant load were assessed. Niobium oxide demonstrated to be an effective catalyst, selectively converting the nerol (model molecule) to epoxide and aldehyde. Oxidation of various terpenic alcohols was investigated. Only geraniol and nerol were selectively epoxidized, suggesting a hydroxyl group assisted reaction. Although being also allylic alcohol, linalool was unreactive toward epoxidation due to the presence of a methyl group at the same carbon atom than the hydroxy group. The use of an environmentally cheap friendly oxidant (H2O2) and efficient solid catalyst (Nb2O5) are positive aspects of this process.
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    Preparation, characterization and catalytic application of Barium molybdate (BaMoO4) and Barium tungstate (BaWO4) in the gas-phase oxidation of toluene.
    (2017) Alencar, Lorena Dariane da Silva; Mesquita, Alexandre; Feitosa, Carlos Alberto Carneiro; Balzer, Rosana; Probst, Luiz Fernando Dias; Batalha, Daniel Carreira; Rosmaninho, Marcelo Gonçalves; Fajardo, Humberto Vieira; Bernardi, Maria Inês Basso
    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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    Room temperature selective conversion of aniline to azoxybenzene over an amorphous niobium oxyhydroxide supported on δ-FeOOH.
    (2018) Lima, André L. D.; Batalha, Daniel Carreira; Fajardo, Humberto Vieira; Rodrigues, Jairo Lisboa; Pereira, Márcio César; Silva, Adilson Cândido da
    In this work, catalysts for the oxidation of aniline into azoxybenzene were prepared by combining δ-FeOOH nanoparticles with 0, 2.5, 5, and 10 wt.% niobium oxyhydroxides by a simple co-precipitation method. The niobium oxyhydroxide actively changed the chemical and textural properties of δ-FeOOH, as verified by XRD, Mössbauer spectroscopy, N2 adsorption-desorption measurements, and TEM images. Therefore, the catalytic performance of δ-FeOOH to convert aniline into azoxybenzene in the presence of hydrogen peroxide was significantly improved. The catalytic activity and selectivity changed with the Nb content in the composite. The effect of different reaction parameters like solvent type, H2O2 volume, and reaction time has been studied in detail. The catalyst with 10 wt.% Nb was the most efficient among the evaluated catalysts, showing 100% conversion of aniline with 80.2% selectivity to azoxybenzene when propanol was used as solvent at 25 °C. Moreover, the catalyst 10 wt.% Nb exhibited good stability and could be reused for various cycles without significant loss of catalytic activity.
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    Sub-15 nm CeO2 nanowires as an efficient nonnoble metal catalyst in the room-temperature oxidation of aniline.
    (2018) Silva, Anderson Gabriel Marques da; Batalha, Daniel Carreira; Rodrigues, Thenner Silva; Candido, Eduardo Guimarães; Luz, Sulusmon Cesar; Freitas, Isabel Cristina de; Fonseca, Fabio Coral; Oliveira, Daniela Coelho de; Taylor, Jason Guy; Torresi, Susana Ines Cordoba de; Camargo, Pedro Henrique Cury; Fajardo, Humberto Vieira
    We described herein the facile synthesis of sub-15 nm CeO2 nanowires based on a hydrothermal method without the use of any capping/stabilizing agent, in which an oriented attachment mechanism took place during the CeO2 nanowire formation. The synthesis of sub-15 nm CeO2 nanowires could be achieved on relatively large scales (∼2.6 grams of nanowires per batch), in high yields (>94%), and at low cost. To date, there are only a limited number of successful attempts towards the synthesis of CeO2 nanowires with such small diameters, and the reported protocols are typically limited to low amounts. The nanowires displayed uniform shapes and sizes, high surface areas, an increased number of oxygen defects sites, and a high proportion of Ce3+/Ce4+ surface species. These features make them promising candidates for oxidation reactions. To this end, we employed the selective oxidation of aniline as a model transformation. The sub-15 nm CeO2 nanowires catalyzed the selective synthesis of nitrosobenzene (up to 98% selectivity) from aniline at room temperature using H2O2 as the oxidant. The effect of solvent and temperature during the catalytic reaction was investigated. We found that such parameters played an important role in the control of the selectivity. The improved catalytic activities observed for the sub-15 nm nanowires could be explained by: i) the uniform morphology with a typical dimension of 11 ± 2 nm in width, which provides higher specific surface areas relative to those of conventional catalysts; ii) the significant concentration of oxygen vacancies and high proportion of Ce3+/Ce4+ species at the surface that represent highly active sites towards oxidation reactions; iii) the crystal growth along the (110) highly catalytically active crystallographic directions, and iv) the mesoporous surface which is easily accessible by liquid substrates. The results reported herein demonstrated high activities under ambient conditions, provided novel insights into selectivities, and may inspire novel metal oxide-based catalysts with desired performances