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INAMAT² organiza este seminario que se celebrará el día 15 de mayo de 2025 a las 10:00h. en la sala de conferencias del edificio Jerónimo de Ayanz.

Abstract:

Water electrolysis presents a promising, eco-friendly solution for renewable electricity storage, but the slow anodic oxygen evolution reaction (OER) typically requires rare and costly iridium-based catalysts to operate under harsh acidic conditions. Recent advancements have introduced the potential of anion-exchange membranes (AEM) for electrolysis in alkaline media, offering a cost-effective alternative to proton exchange membranes (PEM). This shift opens up exciting opportunities to replace iridium with more abundant, lower-cost transition metal oxides (TMOs). Among these, spinel-structured TMOs have garnered attention due to their relatively low synthesis temperature, which maintains high surface area, and their tunable properties based on composition. While Co3O4 and mixed Fe/Co/Ni ferrites are promising OER catalysts, their low electrical conductivity requires the addition of carbon, which is unstable under OER conditions and prone to corrosion.
In response to this challenge, we present a novel approach involving the design of core-shell nanoparticles (Fe3O4@CoFe2O4).1 By combining a conductive iron oxide core (Fe3O4) with an electrocatalytic cobalt-ferrite shell (CoFe2O4), we achieved remarkable OER performance, with an outstanding specific activity of 2800 A/gcobalt at 1.65 V vs. RHE.2,3 Our study investigates how key parameters such as core size and nanoparticle film thickness influence the OER efficiency. Furthermore, we employed operando near-edge X-ray absorption fine structure (NEXAFS) spectroscopy to probe the redox behavior of these core-shell nanoparticles during OER, providing valuable insights into the underlying reaction mechanism.