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Catalizadores a base de hierro con actividad mejorada de reducción de oxígeno en pilas de combustible de electrolito
Michel Lefèvre1, Eric Proietti, Frédéric Jaouen
1Institut National de la Recherche Scientifique, Energie, Matériaux et Télécommunication, Varennes, Québec J3X 1S2, Canada.
Science (New York, N.Y.)
|April 4, 2009
Resumen
Los investigadores desarrollaron catalizadores avanzados a base de hierro para pilas de combustible, aumentando significativamente los sitios activos. Estos catalizadores ahora rivalizan con el rendimiento del platino, ofreciendo una alternativa prometedora para aplicaciones de energía limpia.
Área de la Ciencia:
- La electroquímica es electroquímica.
- Ciencia de los materiales Ciencia de los materiales.
- La catálisis de la catálisis.
Sus antecedentes:
- Los catalizadores a base de hierro son menos competitivos que el platino para la reducción de oxígeno en las células de combustible de membrana de electrolito de polímero debido a la baja densidad del sitio activo.
- El desarrollo de alternativas eficientes y rentables al platino es crucial para el avance de la tecnología de celdas de combustible.
Objetivo del estudio:
- Para mejorar la densidad del sitio activo de los catalizadores a base de hierro para la reacción de reducción de oxígeno (ORR).
- Para lograr un rendimiento comparable al de los catalizadores de platino en las pilas de combustible de membrana de electrolito de polímero (PEMFC).
Principales métodos:
- Catalizadores basados en hierro con soporte de carbono microporosos sintetizados.
- Utilizó una ruta de síntesis que involucra la fenantrolina de molienda de bolas y acetato ferroso con un soporte de carbono, seguido de pirólisis dual (argon y luego amoníaco).
- Caracterizó la estructura del catalizador, centrándose en los cationes de hierro coordinados por nitrógeno piridínico dentro de microporos grafíticos.
Principales resultados:
- El método de síntesis optimizado aumentó significativamente la densidad de los sitios activos.
- El electrocatalizador a base de hierro resultante logró una densidad de corriente comparable a los catalizadores de platino a una carga de 0,4 mg Pt/cm2.
- El catalizador demostró un alto rendimiento a una tensión de la célula mayor o igual a 0,9 V.
Conclusiones:
- El catalizador a base de hierro desarrollado exhibe un rendimiento competitivo para la reacción de reducción de oxígeno en PEMFCs.
- La estrategia de síntesis mejora efectivamente la densidad del sitio activo, abordando una limitación clave de los catalizadores de hierro anteriores.
- Este avance presenta una alternativa viable y potencialmente de menor costo al platino en aplicaciones de celdas de combustible.
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