UTN- FRC -Producción Académica de Investigación y Desarrollo
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Item 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.Item 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.Item Green hydrogen from catalytic ammonia decomposition(2021) Gómez Costa, Marcos B.; Juárez, Juliana M.; Anunziata, Oscar A.Ir/γ-alumina catalysts for decomposition of ammonia were prepared by Iridium ion exchange procedure, onto γ-alumina synthesized by sol-gel method. In order to determine the physical and chemical properties we used X ray diffraction (XRD) analysis, Fourier transformed infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and nuclear magnetic resonance (NMR-MAS). The samples displayed the characteristic band at 1620 cm-1 corresponds to a N-H bending of ammonia adsorbed on electron-acceptor sites, and the characterization by pyridine adsorption and desorption to determine the presence of Lewis acid sites, with absence of Brønsted sites, showing higher acid strength than commercial sample used as reference. The analysis of particle size and morphology reveal uniformity, with tendency to a spheroid aspect and smaller to 3 μm of diameter. The 27Al NMR-MAS test, allowed determining the tetrahedral and octahedral aluminum presence in both samples, where the higher proportion of octahedral Al in γ-alumina synthesized by us, is correlated toward the greater electron acceptor acid sites. The designed method was effective for Ir/γ-alumina catalysts synthesis. The surface area was 150 and 260 m2/g for the commercial sample and the alumina prepared by and us, and after the Ir incorporation (10-18% w/w in both samples), they surfaces were reduced approximately 5.4-8.8% and 4.3-7.2% respectively. XRD analyses show the absence of maximums at 28º and 34.7º 2 corresponding to iridium oxide, indicating a high efficiency of the reduction treatment, increasing the active sites for the specific reaction of ammonia decomposition. The distribution of the Ir crystallites determined by XRD and TEM indicated that, the samples prepared by ion exchange method produced smaller Iridium clusters than by impregnation procedure of alumina sample, with higher surface area and greater anchorage sites. According to preliminary catalytic tests, the Ir/γ-alumina catalysts prepared by a novel method showed higher activity to ammonia decomposition to N2 and green H2.