Browsing by Author "Honores, Jessica"

Now showing 1 - 7 of 7
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    Carbon dioxide electrochemical reduction by copper nanoparticles/ionic liquid-based catalytic inks
    (2024) Gazzano, Valeria; Mardones-Herrera, Elias; Saez-Pizarro, Natalia; Armijo, Francisco; Martinez-Rojas, Francisco; Ruiz-Leon, Domingo; Honores, Jessica; Isaacs, Mauricio
    The development of copper nanoparticle (CuNP)-based catalysts for the electrochemical reduction of carbon dioxide (ECO2-R) offers a promising approach to enhance its transformation into other industrially significant compounds. This study reports ECO2-R at -1.3 V vs RHE using CuNPs and catalytic inks composed of CuNPs and ionic liquids (ILs), observing significant differences in the selectivity of each catalyst. Specifically, CuNPs alone show a preference for producing ethylene and aqueous products, such as formic acid, ethanol, and formaldehyde. In contrast, the addition of ILs to the catalytic system redirects selectivity toward gaseous products, with methane being the main product. These findings highlight the potential to optimize catalyst composition to tailor the selectivity of CO2 conversion processes. ILs modify the catalytic environment and influence reaction pathways, enabling the selection of specific products.
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    Electrodetermination of Gallic Acid Using Multi-walled Carbon Nanotube Paste Electrodes and N-Octylpyridinium Hexafluorophosphate
    (WILEY-V C H VERLAG GMBH, 2022) Gidi, Leyla; Honores, Jessica; Ibarra, Jose; Jesus Aguirre, Maria; Arce, Roxana; Ramirez, Galo
    In this work, the determination of gallic acid was performed using surface-renewable carbon paste electrodes fabricated with multi-walled carbon nanotubes (MWCNT) and a mixture of N-octylpyridinium hexafluorophosphate (OPyPF6) ionic liquid with mineral oil (MO) as binder. This system shows remarkable amperometric sensor characteristics and promotes a better electronic transfer. An electroanalytical study of gallic acid shows a linear range from 4.98 +/- 0.25 to 74.1 +/- 2.2 mu mol L-1, with R-2=0.9958 and an experiment a limit of detection of 2.70 +/- 0.08 mu mol L-1 (S/N=3), and a sensitivity of 0.029 mu A mu mol(-1) L.
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    Phenoxy- and Phenylamino-Heterocyclic Quinones: Synthesis and Preliminary Anti-Pancreatic Cancer Activity
    (WILEY-V C H VERLAG GMBH, 2022) Sanchez, Patricio; Salas, Cristian O.; Gallardo-Fuentes, Sebastian; Villegas, Alondra; Veloso, Nicolas; Honores, Jessica; Inman, Martyn; Isaacs, Mauricio; Contreras, Renato; Moody, Christopher J.; Cisterna, Jonathan; Brito, Ivan; Tapia, Ricardo A.
    The successful application of fragment-based drug discovery strategy for the efficient synthesis of phenoxy- or phenylamino-2-phenyl-benzofuran, -benzoxazole and -benzothiazole quinones is described. Interestingly, in the final step of the synthesis of the target compounds, unusual results were observed on the regiochemistry of the reaction of bromoquinones with phenol and aniline. A theoretical study was carried out for better understanding the factors that control the regiochemistry of these reactions. The substituted heterocyclic quinones were evaluated in vitro to determine their cytotoxicity by the MTT method in three pancreatic cancer cell lines (MIA-PaCa-2, BxPC-3, and AsPC-1). Phenoxy benzothiazole quinone 26a showed potent cytotoxic activity against BxPC-3 cell lines, while phenylamino benzoxazole quinone 20 was the most potent on MIA-PaCa-2 cells. Finally, electrochemical properties of these quinones were determined to correlate with a potential mechanism of action. All these results, indicate that the phenoxy quinone fragment led to compounds with increased activity against pancreatic cancer cells.
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    Quick and Easy Modification of Glassy Carbon Electrodes with Ionic Liquid and Tetraruthenated Porphyrins for the Electrochemical Determination of Atrazine in Water
    (2019) Calfuman, Karla; Honores, Jessica; Isaacs, Mauricio; Quezada, Diego; Valdebenito, Javier; Urzua, Marcela
    Atrazine is a pesticide used to control broadleaf weeds, however its wide distribution and its high persistence in the soil and in surface waters has resulted in a public and environmental health problem. Present results shows the design, construction and characterization of glassy carbon electrodes modified with tetrarutenated metalloporphyrin (M=Ni (II) and Zn (II)) and 1-butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide, BMIMNTF2. The modification was reproducible and sensitive for the electrochemical detection of atrazine in neutral media. The detection limit was 230 nM when using GC/BMIMNTF2/ZnTRP and 540 nM with GC/BMIMNTF2/NiTRP, meaning that his methodology can be a feasible and inexpensive way to detect atrazine in trace levels.
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    Study of the Hydrogen Evolution Reaction Using Ionic Liquid/Cobalt Porphyrin Systems as Electro and Photoelectrocatalysts
    (MDPI, 2020) Gidi, Leyla; Honores, Jessica; Ibarra, Jose; Arce, Roxana; Aguirre, M. J.; Ramirez, Galo
    In this work, the design and manufacture of graphite paste (Gr) electrodes is carried out, including N-octylpyridinium hexafluorophosphate (OPyPF6) ionic liquid (IL) as binder and modification with Co-octaethylporphyrin (Co), in order to study the hydrogen evolution reaction (HER) in the absence and presence of light. The system is characterized by XRD and FESEM-EDX (Field Emission Scanning Electron Microscopy with Energy Dispersive X-Ray Spectroscopy), confirming the presence of all the components of the system in the electrode surface. The studies carried out in this investigation confirm that a photoelectrocatalytic system towards HER is obtained. The system is stable, efficient and easy to prepare. Through cyclic voltammetry and electrochemical impedance spectroscopy, was determined that these electrodes improve their electrochemical and electrical properties upon the addition of OPyPF6. These effects improve even more when the systems are modified with Co porphyrin. It is also observed that when the systems are irradiated at 395 nm, the redox process is favored in energy terms, as well as in its electrical properties. Through gas chromatography, it was determined that the graphite paste electrode in the presence of ionic liquid and porphyrin (Gr/IL/Co) presents a high turnover number (TON) value (6342 and 6827 in presence of light) in comparison to similar systems reported.
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    Study of the reaction mechanism in hydrogen production using metal-free Schiff base as a catalyst
    (2023) Muena, Juan Pablo; Zamora, Pedro Pablo; Bieger, Klaus; Soliz, Alvaro; Haribabu, Jebiti; Aguirre, Maria Jesus; Marquez, Paulina; Quezada, Diego; Honores, Jessica
    Understanding the hydrogen evolution reaction and its mechanism is crucial for numerous practical applications in the realm of green energy. The development and discovery of new technologies or alternatives hold great significance in generating hydrogen at a low cost. In this study, we propose a novel catalyst, N, N'-bis(2-hydroxy1-naphthaldehyde)-o-phenylenediamine ([naph]2-o-ph), which is a Schiff base, for hydrogen production. The novelty lies in utilizing the organic Schiff base system and the proposed mechanism for hydrogen evolution, involving protonation and electron exchange on the Schiff base. Both experimental and theoretical results highlight the high capability of the Schiff base in generating hydrogen, providing valuable insights for potential applications in water electrolysis.
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    Zinc Stannate as anode and Pyrrolidinium-Based Room Temperature Ionic Liquid as electrolyte for Lithium-ion Cells
    (2021) Quezada, Diego; Honores, Jessica; Ruiz-Leon, Domingo
    With the aim to design safer batteries, pyrrolidinium-based room temperature ionic liquids (RTIL) have been used as electrolytes in Li-ion batteries using zinc stannate as the anodic material. The lithium diffusion coefficients were calculated using Electrochemical Impedance Spectroscopy (EIS) data and were 2.37 x 10(-12) cm(2)s(-1) for MPPyrTFSI and 1.29 x 10(-12) cm(2)s(-1) for BMPyrTFSI. The performance of the device strongly depended on the cation chemical structure, yielding different specific capacity values of 306.3 mAhg(-1) for BMPyrTFSI and 269.2 mAhg(-1) for MPPyrTFSI.