Facultad Regional Córdoba

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Author: search.filters.author.Martínez, María LauraSubject: search.filters.subject.Synthesis

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Now showing 1 - 5 of 5
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    Influence of vanadium nanoclusters in hydrogen uptake using hybrid nanostructured materials
    (Springer Science+Business Media, 2018) Juárez, Juliana María; Gómez Costa , Marcos Bruno; Martínez, María Laura; Anunziata, Oscar Alfredo
    In this work, we report the synthesis and characterization of vanadium oxide nanoclusters (V2O5) supported in silica nano- structured material (SBA-15) and nanostructured carbon (CMK-3). This material is promising in hydrogen adsorption and storage application for energy harvesting. The materials with vanadium oxide nanoclusters (VxOy-SBA-15 and VxOy-CMK-3) were successfully synthesized and characterized by X-ray diffraction, textural properties, UV–Vis-DRS, X-ray photoelec- tron spectroscopy, temperature programmed reduction and transmission electron microscopy analyses. VxOy-SBA-15 and VxOy-CMK-3 improved significantly the H2 storage behavior (1.33 wt% and 3.43 wt% at 77 K and 10 bar) compared with their respective supports SBA-15 and CMK-3. The materials synthesized are promising in hydrogen uptake by weak link forces (physisorption). A mechanism of hydrogen adsorption was proposed and V5+ cation roll in hydrogen uptake was discussed
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    Optimización de la sínstesis del material mesoestructurado SBA-3 mediante diseño experimental
    (CICat, 2016) Ponte , María Virginia; Rivoira, Lorena Paola; Cussa, Jorgelina; Martínez, María Laura; Beltramone, Andrea Raquel
    hexagonal, diámetro de poro >3nm; presenta alta área superficial y alto volumen de poro. Se utilizó la metodología de Superficie de Respuesta para el modelado y optimización de las condiciones de síntesis de SBA‐3. Se analizaron como factores del Diseño la influencia de la relación molar entre el surfactante (CTAB) y la fuente de silicio (TEOS), el tiempo de envejecimiento, la temperatura y el pH de la síntesis utilizando HCl. La respuesta analizada fue la intensidad de difracción de rayos X para el plano [100]. Las superficies de respuestas se obtuvieron con el diseño Box–Behnken, buscando la combinación de los parámetros que dieran como resultado la mejor estructura en el material sintetizado. Mediante la aplicación de metodología estadística, los mayores valores de la función objetivo (intensidad de DRX para el plano [100]) se obtuvieron utilizando valores de la relación molar CTAB/TEOS de 0,07‐0,16; HCl/TEOS de 8‐11; temperatura de síntesis de 35‐45 (ºC) y tiempos de envejecimiento de 12‐24hr.
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    Multiple-wall carbon nanotubes obtained with mesoporous material decorated with ceria-zirconia
    (2020) Rodríguez, Miguel Angel; Anunziata, Oscar Alfredo; Beltramone, Andrea Raquel; Martínez, María Laura
    In this work, Ceria-Zirconia on ordered Santa Barbara mesoporous silica (Ce-Zr-SBA-15), has been used directly as a catalyst for the synthesis of carbon nanotubes (CNTs) through Chemical Vapor Deposition (CVD). In addition to cerium oxide, it contains zirconium oxide nano crystallites, which act as catalysts for carbon nanostructures. The catalytic performance of this material was evaluated for the decomposition of ethanol at 900 °C, with N2 flow. The carbon decomposed from absolute ethanol diffuses through the surface of the nanostructured catalytic material and precipitates in the form of MWCNT structures, which could be identified by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM), showing average diameters of 30–35 nm.
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    Mesopore carbón starch with acid properties: synthesis and characterization
    (2020) Martínez, María Laura; Anunziata, Oscar A.
    We have shown that a promising material with acidic properties can be successfully prepared from starch mesoporous carbon (SMC), functionalized with sulfated zirconia. The process of assembling P123, starch, zirconia, and silicon synthesized Zr-modified ordered mesoporous carbon. SMC and Zr-SMC were characterized by BET for their texture properties and, using Scanning Electron Microscopy (SEM), their morphology. Acidic properties were acquired by programmed thermodesorption of ammonia (NH3 TPD). These studies show that the Zr-SMCs material is mainly composed of mesopores with an average pore size of approximately 3.5 nm, high surface area and pore volume, and has medium to strong acidity properties.
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    Multiple-wall carbón nanotubes obtained with mesoporous material decorated with cerio-zirconium
    (2020) Martínez, María Laura; Anunziata, Oscar A.
    In this work, Ce-Zr-SBA-15 has been used directly as a catalyst for the synthesis of multi-vall carbon nanotubes (MWCNT) through Chemical Vapor Deposition (CVD). In addition to cerium oxide, it contains zirconium oxide Nano crystallites, which act as catalysts for carbon nanostructures. The catalytic performance of this material was evaluated for the decomposition of ethanol at 900 °C, with N2 flow. The structural characterization of the resulting catalyst was carried out by means of SEM and XRD. The decomposed carbon of absolute ethanol diffuses through the surface of the nanostructured material and precipitates in carbon structures called multiple-walled nanotubes, which could be visualized/detected/identified by TEM, showing diameters of the carbon nanotubes that range from 15 to 25 nm.