UTN- FRC -Producción Académica de Investigación y Desarrollo

Permanent URI for this communityhttp://48.217.138.120/handle/20.500.12272/1932

Browse

Author: search.filters.author.Juárez , Juliana MaríaSubject: search.filters.subject.Mesoporous Carbón

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Bimetallic platinum/iridium modified mesoporous catalysts applied in the hydrogenation of HMF.
    (Universidad Tecnológica Nacional Regional Córdoba., 2018) Ledesma , Brenda Cecilia; Juárez , Juliana María; Beltramone , Andrea Raquel; Beltramone , Andrea Raquel; Juárez , Juliana María
    The catalytic transformation of 5-hydroxymethylfurfural (HMF) to produce 2,5-dimethylfuran (DMF) was studied over bimetallic (PtIr) and monometallic (Pt) catalysts supported on CMK-3 and SBA-15 mesoporous materials. The optimum temperature and pressure for the maximum production of DMF were 120° and 15 atm. Increases in temperature and pressure decreased the selectivity to DMF. The catalysts were broadly characterized by XRD, N2-isotherms, XPS, TPR, TEM and NH3-TPD. It was found that the metal particles were well reduced and highly dispersed on the surface of the support of large surface area and narrow pore distribution. The PtIr alloy species active sites were very active and selective towards the formation of the desired DMF. PtIr-CMK-3 showed an excellent activity, selectivity and stability to be applied in this process.
  • Thumbnail Image
    Item
    Novel mesoporpous carbon modified with zirconia for hydrogen adsorption.
    (Univesidsad Tecnológica Nacional., 2021) Venosta, Lisandro; Juárez , Juliana María; Anunziata , Oscar Alfredo; Gómez Costa, Marcos Bruno; Anunziata , Oscar Alfredo; Juárez , Juliana María
    Nanostructured carbon material (CMK-3) modified with zirconium oxide was synthesized by a new direct synthesis technique. Zirconium oxide dispersed in carbon materials (Zr-CMK-3) were characterized by X-ray diffraction, textural properties, UV-Vis-DRS, XPS, and transmission electron microscopy analysis. The goal of this new synthesis method is to avoid the use of inorganic siliceous template (SBA-15), which leads to a shorter and cheaper way to obtain mesoporous carbon, and at the same time incorporate into the framework Zirconium atoms. Zr-CMK-3 material significantly improved H2 storage behaviour (4.6% by weight at 77 K and 10 bar) compared to CMK-3 support. The synthesized material is promising in the absorption of hydrogen by weak bonding forces (physisorption). The activity of the samples to the adsorption of hydrogen molecules is attributed to the improved dispersion of the zirconium oxide, as well as the appropriate use of support, which can probably disperse the zirconium on its large surface area, allowing a great dispersion of the zirconium. The Zr+4 cation is an active species to absorb and store hydrogen through a physisorption process and the carbon plays an important role in the dispersion and size of metal particles. A hydrogen storage mechanism on the active surface of the ZrO2 clusters was proposed. First layer of hydrogen molecules can react with the metal cation through a dihydrogen complex (Kubas interaction). The second layer of hydrogen molecules adsorbed around the metal oxide clusters is due to dipole-like interactions, this is because the metal particle induces dipole forces on the hydrogen molecule. The other layers could also interact by dipole forces; however, the interaction force decreases as the distance to the surface increases. The upper layers could interact with the metal cation by dipole-induced bonding; however, the interaction force decreases as the distance to the surface increases.