Peculiar Properties of the La0.25Ba0.25Sr0.5Co0.8Fe0.2O3−δ Perovskite as Oxygen Reduction Electrocatalyst
2023
Chiara Aliotta | Maria Costa | Leonarda Francesca Liotta | Valeria La Parola | Giuliana Magnacca | Francesca Deganello
The electrochemical reduction of molecular oxygen is a fundamental process in Solid Oxide Fuel Cells and requires high efficiency cathode materials. Two La0.25Ba0.25Sr0.5Co0.8Fe0.2O3&minus:&delta:-based perovskite compounds were prepared by solution combustion synthesis, and characterized for their structural, microstructural, surface, redox and electrochemical properties as potential cathodes in comparison with Ba0.5Sr0.5Co0.8Fe0.2O3&minus:&delta: and La0.5Sr0.5Co0.8Fe0.2O3&minus:&delta: perovskites. Results highlighted that calcination at 900 °:C led to a &ldquo:bi-perovskite heterostructure&rdquo:, where two different perovskite structures coexist, whereas at higher calcination temperatures a single-phase perovskite was formed. The results showed the effectiveness of the preparation procedures in co-doping the A-site of perovskites with barium and lanthanum as a strategy to optimize the cathode&rsquo:s properties. The formation of nanometric heterostructure co-doped in the A-site evidenced an improvement in oxygen vacancies&rsquo: availability and in the redox properties, which promoted both processes: oxygen adsorption and oxygen ions drift, through the cathode material, to the electrolyte. A reduction in the total resistance was observed in the case of heterostructured material.
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