Browsing by Author "Correa-Encalada, Daniel"

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    Comparison of Different Synthetic Routes of Hybrid Hematite-TiO2 Nanotubes-Based Electrodes
    (2021) Fornazari, Ana Luiza; Castillo-Rodriguez, Judith; Correa-Encalada, Daniel; Dalchiele, Enrique A.; Hevia, Samuel A.; del Rio, Rodrigo
    Nowadays, green hydrogen is an important niche of interest in which the search for a suitable composite material is indispensable. In this sense, titanium oxide nanotubes (TiO2 nanotube, TNTs) were prepared from double anodic oxidation of Ti foil in ethylene glycol electrolyte. The morphology of the nanotubes was characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Once characterized, nanotubes were used as templates for the deposition of hematite. The use of three synthetic procedures was assayed: Chemical Vapor Deposition (CVD), Successive Ionic Layer Adsorption and Reaction (SILAR), and electrochemical synthesis. In the first case, CVD, the deposition of hematite onto TiO2 yielded an uncovered substrate with the oxide and a negative shift of the flat band potential. On the other hand, the SILAR method yielded a considerable amount of hematite on the surface of nanotubes, leading to an obstruction of the tubes in most cases. Finally, with the electrochemical synthesis, the composite material obtained showed great control of the deposition, including the inner surface of the TNT. In addition, the impedance characterization showed a negative shift, indicating the changes of the interface electrode-electrolyte due to the modification with hematite. Finally, the screening of the methods showed the electrochemical synthesis as the best protocol for the desired material.
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    Fabrication of Translucid Gold-nanocellulose Electrodes and Their Potential Application as Hydrogen Peroxide Sensor
    (2021) Kroff, Macarena; Luiza Fornazari, Ana; Correa-Encalada, Daniel; Jose Rubio, Maria; Hevia, Samuel A.; Rio, Rodrigo
    In this work, we describe the fabrication of a transparent gold electrode based on nanocellulose. The electrode was prepared via electron beam evaporation of gold onto nanocellulose films previously spread over a glass slip. Electrodes with different thickness of Au was fabricated, and the material's optical, morphological and electrical properties were assessed. Finally, as a proof of concept, a possible application of this electrode in hydrogen peroxide sensing was performed. The results show that a thin layer of gold on a nanocellulose translucid film allows obtaining a conductive transparent surface that could be used to design a transparent electrode.