Santaya M, Jimenez CE, Esteban Troiani H, Carbonio EA, Damian Arce M, Maria Toscani L, Garcia-Diez R, Wilks RG, Knop-Gericke A, Bär M, Veronica Mogni L (2022)
Publication Type: Journal article
Publication year: 2022
DOI: 10.1039/d2ta02959f
The development of redox stable oxide perovskite - based electrodes for cost-effective symmetric solid oxide fuel cells (SOFCs) that can work at intermediate temperatures and compete with state-of-the-art cathodes and anodes is becoming a concrete possibility. The Ni-doped STF perovskite Sr0.93Ti0.3Fe0.63Ni0.07O3-delta meets such requirements by exsolving catalytically active Ni-Fe nanoparticles in reducing atmospheres that boost anode performance. This work aims at clarifying whether exsolution is a reversible process, which could extend the lifetime of SOFCs. Element-specific synchrotron - based near-ambient pressure X-ray photoelectron and absorption spectroscopies are key to understanding the exsolution/reoxidation processes of the Ni-Fe nanoparticles during redox cycling in the atmosphere. This study reveals that Ni exsolves easily, dragging along the more stable Fe to form nanoalloyed Ni-Fe even under mild reducing conditions. A significant Sr-surface segregation indicates that the initial Sr-deficiency cannot fully compensate for the B-site cation depletion during exsolution. Switching to an oxidizing atmosphere results in a reoxidation-induced reconstruction of the electrode, in which a Fe- and Sr-rich oxide layer forms on the surface, leaving the Ni segregated from the perovskite. This reoxidized electrode shows a significantly improved cathode response in comparison to the pristine perovskite, indicating changes in the mechanisms that activate the oxygen reduction reaction.
APA:
Santaya, M., Jimenez, C.E., Esteban Troiani, H., Carbonio, E.A., Damian Arce, M., Maria Toscani, L.,... Veronica Mogni, L. (2022). Tracking the nanoparticle exsolution/reoxidation processes of Ni-doped SrTi0.3Fe0.7O3-delta electrodes for intermediate temperature symmetric solid oxide fuel cells. Journal of Materials Chemistry A. https://doi.org/10.1039/d2ta02959f
MLA:
Santaya, Mariano, et al. "Tracking the nanoparticle exsolution/reoxidation processes of Ni-doped SrTi0.3Fe0.7O3-delta electrodes for intermediate temperature symmetric solid oxide fuel cells." Journal of Materials Chemistry A (2022).
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