UTN- FRC -Producción Académica de Investigación y Desarrollo - Artículos
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Item Ga-SBA-3 A novel nanostructured material: synthesis, characterization and application(IOP Publishing, 2019) Martínez, María Laura; Gómez Costa , Marcos Bruno; Anunziata, Oscar AlfredoThis paper reports for the first time the incorporation of gallium into the structure of the mesoporous SBA-3 material in order to modify the intrinsic acidity of the material. The study indicates the effective incorporation of Ga into a network in tetrahedral form, with most in the interior of the lodging and a low proportion on the external surface. Gallium was introduced via post-synthesis using Ga-nitrate in appropriate conditions. The nanostructured material was characterized by ICP, x-ray diffraction, nuclear magnetic resonance-MAS, x-ray photoelectron spectra, FTIR, SEM, transmission electron microscopy and UV–vis. Pyridine was used as a probe molecule for the determination of its acidity following the amount and type of acidic sites by FTIR. In addition, aniline adsorption/desorption studies and subsequent in situ polymerization, polyaniline (PANI)/Ga-SBA-3, were carried out with the aim of producing a nanocomposite with conductive properties. The original material had good structural regularity and acidity of Brønsted and Lewis; the PANI/Ga-SBA-3 composite also showed a conductivity of 2.5 × 10−3 S cm−1, higher than that of its homologs Al-SBA-3 and Al-MCM- 41.Item 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 AlfredoIn 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 discussedItem 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 Raquelhexagonal, 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.Item Ordered mesoporous carbons (OMC) type CMK-3 modified with Vandium for improvement H2 storage(Diamond and Carbon Conference Organization, 2018) Juárez, Juliana María; Gómez Costa , Marcos Bruno; Martínez, María Laura; Anunziata, Oscar Alfredo; Martínez, María LauraSome previous studies probed that H2 adsorption can be improved for mesoporous carbons introducing into the framework of the nanomaterial some metals or oxides, like platinum, Zn, ZnO, Ni, NiO, or TiO2. Some other authors have made several efforts in the same direction, for instance, incorporated iron and copper nanoparticles into multiwalled carbon nanotubes and studied their hydrogen adsorption. In this work we studied the influence of the incorporation of vanadium nanoparticles inside the channels of mesoporous carbon CMK-3. This research includes the synthesis of the mesoporous silicate, (hard Template) and the synthesis of the CMK-3 by nanocasting strategy and the incorporation of the vanadium nanoclusters by wetness impregnation. This kind of materials are synthesize by nanocasting strategy using mesoporous silicates as templates and have high surface area (from 1000 to 2000 m2/g) and pore volumes in the range of 0.5 to 1 ml.g-1. Accordingly, CMK-3 was chosen as a support material for hydrogen storage due to its large surface area, high chemical stability, uniform pore diameter, accessible porosity and threedimensional conducting network. The characterization of these nanomaterials was obtained by XRD, N2 adsorption, XPS, TPR and Uv-Vis, TEM, and finally the study of the improvement in the hydrogen adsorption. V5+ cation in V2O5 is an active species to uptake and store hydrogen by a physisorption process and the support plays an important role in metal cluster dispersion and size.Item Novel hybrid Ga-SBA-3 nanostructured material: Synthesis, Characterization and Applications(., 2018) Martínez, María Laura; Gómez Costa , Marcos Bruno; Beltramone, Andrea Raquel; Anunziata, Oscar AlfredoIn this work we study the incorporation of gallium in the structure of the SBA-3 mesoporous material, with the purpose of modifying the intrinsic acidity of the material using pyridine in order to determine the acidic sites that this material possesses. In addition, studies of adsorption / desorption of aniline and its subsequent polymerization on the mesoporous Ga-SBA-3, that gives the unique hybrids compound, with conductive characteristics similar to those of an inorganic semiconductor. Si-SBA-3 was prepared using CTABr and TEOS, as surfactant and Si source respectively. To obtain Ga-SBA-3 post-synthesis incorporation was employed. Ga-SBA-3 were dehydrated at 400 ° C under vacuum and then were exposed to vapors of pyridine / liquid aniline depending on the studies to be performed (pyridine to determine the acid sites of the material and aniline for subsequent polymerization) at vacumm. The in-situ polymerization of aniline was carried out to produce PANI/Ga-SBA-3. The final PANI/Ga-SBA-3 material was characterized by XRD, ICP, SEM-EDX, FTIR, BET. Direct current electrical conductivity measurements were performed using pellets and a four-probe technique, improving the contacts with a gold layer. Higher amount of polyaniline in conductive emeraldine salt form was found in PANI/Ga-SBA-3 composite, with respect to other composites reported in the literature. At room temperature (273 K), the electrical conductivity of PANI/Ga-SBA-3 was 2.5x10-3 S/cm, higher than its of Al-SBA-3 and Al-MCM- 41 homologs. To explain the conductivity of the composite (nanowire of PANI within Ga-SBA-3), we must consider the configuration of the nanostructured material and the type of PANI anchoring.Item Nanotubos de carbono de pared múltiple obtenidos con materila mesoporoso decorado con cerio-circonio(Universidad Tecnológica Nacional. Facultad Regional Córdoba, 2019) Rodríguez, Miguel Ángel; Anunziata , Oscar Alfredo; Beltramone, Andrea Raquel; Martínez, María LauraEn este trabajo, se ha empleado Ce-Zr-SBA-15 directamente como catalizador para la síntesis de nanotubos de carbono (CNT) a través de deposición química de vapor (CVD). Además del óxido de cerio, contiene nanocristalitos de óxido de circonio, que actúan como catalizadores para nanoestructuras de carbono. El rendimiento catalítico de este material se evaluó para la descomposición de etanol a 900 ° C, con flujo N2. La caracterización estructural del catalizador resultante se realizó por medio de microscopía electrónica de barrido (SEM). El carbono descompuesto de etanol absoluto se difunde a través de la superficie del material nanoestructurado y precipita en estructuras de carbono denominados Nanotubos de pared múltiple, los mismos pudieron visualizarse mediante microscopia electrónica de Transmisión (TEM), mostrando diámetros de los nanotubos de carbono que van desde 15 a 25 nm.Item Influencia de nanoclusters de óxido de vanadio dispersos en materiales nanoestructurados híbridos en el almacenamiento de hidrógeno(RITEQ, 2018) Juárez, Juliana María; Gómez Costa , Marcos Bruno; Martínez, María Laura; Anunziata, Oscar AlfredoEn todo el mundo en las últimas décadas, uno de los temas más preocupantes ha sido la reducción de los combustibles fósiles, junto con el problema del calentamiento global. Estas preocupaciones han convertido al hidrógeno en una alternativa ideal a los recursos fósiles convencionales. Un tipo de OMC, el carbón mesoestructurado de Corea (CMK), se sintetiza mediante la estrategia de nanocasting utilizando silicatos mesoporosos como plantillas; tiene un área superficial alta (de 1000 a 2000 m2 / g) y un volumen de poro en el rango de 0.5 a 1 ml.g-1. Por consiguiente, se eligió el CMK-3 como material de soporte para el almacenamiento de hidrógeno debido a su gran área superficial, alta estabilidad química, diámetro de poro uniforme, porosidad accesible y red tridimensional [Yang et al. (2005), Anbia et al. (2009), Anbia et al. (2011)]. Por otro lado, el material mesoporoso silíceo, SBA-15 muestra redes regulares y un diámetro de poro que fluctúa de 1.5 a 10 nm dependiendo del agente plantilla utilizado en su síntesis. Debido a su tamaño y forma de poros, es un material adecuado como absorbente para una variedad de gases y vapores [Schmidt et al. (1995), Soler-Illia (2002)]. En este trabajo estudiamos la influencia de la incorporación de nanopartículas de vanadio dentro de los canales de dos soportes diferentes, el silicato mesoporoso SBA-15 y el carbón mesoporoso CMK-3. Esta investigación incluye la síntesis del silicato mesoporoso y la síntesis de CMK-3 mediante la estrategia de nanocasting, la incorporación de nanoclusters de vanadio por impregnación de humedad, la caracterización de estos nanomateriales por XRD, adsorción de N2, XPS, TPR y UV-Vis, TEM y el estudio de la mejora en la adsorción de hidrógenoItem Esterification of succinic acid using sulfated zirconia supported on SBA-15(2021) Aguzin, Federico L.; Martínez, María Laura; Beltramone, Andrea Raquel; Padró, Cristina L.; Okulik, NoraCatalytic esterification of succinic acid with ethanol to obtain diethyl succinate (DES), a nontoxic plasticizer, is reported. Three sulfated zirconias supported on SBA-15 [SZ-SBA-15(X)] with Si/Zr molar ratios (X) of 10, 20, and 30 were syn- thesized and characterized. N2 adsorption/desorption isotherms and X-ray dif- fraction patterns evidenced preservation of the ordered mesoporous structure of the catalysts after incorporation of Zr. Yields of DES greater than 85 % were obtained at the final reaction time by using SZ-SBA-15(10) and SZ-SBA-15(20) catalysts, which were higher than those achieved with Amberlyst 36. Reuse of the SZ-SBA-15(20) catalyst showed that, even though the structure of the support was preserved, decreases in sulfur concentration and in the DES yield occurred.Item EXperimental design optimization of the ODS of DBT using vanadium oXide supported on mesoporous Ga-SBA-15(2020) Rivoira, Lorena Paola; Cussa, Jorgelina; Martínez, María Laura; Beltramone, Andrea RaquelEXperiment design-response surface methodology is applied in this work to model and optimize the o Xidation of dibenzothiophene (DBT) using VOX-Ga-SBA-15 catalyst. The analyzed variables are the influence of the nature of the catalyst (V and Ga loading), the s ubstrate/catalyst mass ratio (g DBT/g of catalyst) and the o Xidant/substrate molar ratio (H2O2/DBT). The response analyzed is conversion of DBT at 15 min of reaction time. A set of re- sponse surfaces were obtained applying the BoX-Behnken Design. Based on statistical methodology it was pos- sible to find the best arrangement between the amounts of the gallium heteroatom and the vanadium active species. The higher levels of the objective function were obtained employing the catalyst with 4 wt.% of gallium and 6 wt.% of vanadium; the optimal ratio between g DBT/g of catalyst was 4 and the molar ratio between H2O2/DBT was 5. Gallium incorporation as heteroatom in tetrahedral position allowed the better anchorage ofthe active species of vanadium, generating a very well dispersed catalyst. The optimized catalyst minimized the mass transfer limitation and moreover, was active after several recycles. The best catalyst was likewise very active for the oXidation of the most refractory sulfur compounds as benzothiophene and 4,6-dimetyldi- benzothiopene.Item Indole HDN using iridium nanoparticles supported on titanium nanotubes(2022) Ledesma, Brenda Cecilia; Martínez, María Laura; Gómez Costa, Marcos Bruno; Beltramone, Andrea RaquelThe HDN of indole was studied over iridium modified titanate nanotube catalyst. Titanium nanotube was prepared by the alkaline hydrothermal method. Iridium was added by wetness impregnation. The activity was compared with Ir–TiO2 and commercial NiMo/Al2O3 catalysts. The catalysts prepared were characterized by X-ray diffraction (XRD), N2 adsorption isotherms, UV–Vis-DRS, FTIR, XPS, TEM, Py-FTIR and H2-Chemisorption. XRD, N2 isotherms and UV–vis-DRS con- firmed the nanotube structure. The analysis showed that the mesoporous structure was maintained after Ir incorporation. The results showed that titanate nanotube as support significantly reduce the size of iridium crystallites and improves its dispersion considerably. Iridium titanate nanotube presented abundant and strong Brönsted acidity compared with TiO2 iridium catalyst. According a kinetic study, Ir–TNT was the most active catalyst for indole HDN, in mild conditions in a Batch reactor. The Brönsted acidity in synergic effect with Lewis acidity and hydrogenolysis capacity of iridium species were the responsible for the good activity.