Browsing by Author "Gazzano, Valeria"

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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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    Growth direction and exposed facets of Cu/Cu2O nanostructures affect product selectivity in CO2 electroreduction
    (2022) Castro-Castillo, Carmen; Nanda, Kamala Kanta; Mardones-Herrera, Elias; Gazzano, Valeria; Ruiz-Leon, Domingo; Jesus Aguirre, Maria; Garcia, Gonzalo; Armijo, Francisco; Isaacs, Mauricio
    The electrochemical reduction of CO2 to fuels and value-added chemicals on metallic copper is an attractive strategy for valorizing CO2 emissions. However, favoring the CO2 reduction over hydrogen evolution and exclusive control of selectivity towards C1 or C2+ products by restructuring the copper surface is a major chal-lenge. Herein, we exploit the differential orientation of the exposed facets in copper nanostructures that can tune the product selectivity in CO2 electroreduction. The Cu nanostructure with predominant {111} orientation produce C1 products only upon CO2 electroreduction at an applied potential of-1.3 V vs. reversible hydrogen electrodes (RHE), with 66.57% Faradaic efficiency (FE) for methane. Whereas the vertically grown copper nanostructures that are oriented in {110} direction have higher dislocation density and show greater CO2 electroreduction activity (>95%) at the same applied potential, with FE towards ethylene 24.39% and that of oxygenates 41.31%. FIA-DEMS analysis provided experimental evidence of selectivity of methane over methanol at higher overpotentials indicating the mechanism of methane formation occurs via *COH intermediate. The ethylene formation at a potential-1.0 V vs. RHE or more negative to it suggests a common intermediate for methane and ethylene on the vertically grown copper nanostructures. This work advances the understanding between the product selectivity and the surface structure of the copper nanostructures in electrochemical CO2 reduction.
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    High-performance and low-cost electrochemical reactor for limestone decarbonation applied to clinker production – A validation at laboratory scale
    (2024) Martínez, Natalia P.; Troncoso P., Felipe; Gazzano, Valeria; Ramírez Amaya, Darío Alonso; González Hormazábal, Marcelo Andrés; Navarrete Leschot, Iván Ignacio; Canales Muñoz, Roberto; Dreyse, Paulina
    Limestone decarbonation to obtain CaO (calcium oxide) and produce cement is an industrial activity with enormous CO2 emissions, due to the intrinsic calcination reaction of CaCO3 (calcium carbonate), in addition to the use of fossil fuels. One of the most recent ideas to reduce CO2 emissions in this process has been the electrochemical decarbonation of limestone where Ca(OH)2 (calcium hydroxide) is obtained as an intermediate product that is then used as CaO precursor in clinker synthesis. This study shows the design of a low-cost electrochemical reactor and the optimization of the parameters to produce Ca(OH)2 with high purity and yield from the decarbonation processes of pure CaCO3 and limestone used in the cement industry. In addition, the remaining limestone sludge and electrolytic solutions were analyzed, and it was found that the sludge can be used as a correction material in clinker preparation, and it is also possible to reuse the electrolytic solution twice. Finally, the main finding is the proposal of a new clinker synthesis, which results in a cement with comparable characteristics to those of ordinary Portland cement, using Ca(OH)2 obtained from the electrochemical decarbonation of CaCO3, achieving a reduction in CO2 emissions of approximately 90% compared to the conventional method.