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Estructura compleja de cobalto macrocíclico de catorce miembros como base potencial para catalizadores metálicos no
Zhiqing Feng1, Junya Ohyama2,3, Soutaro Honda1
1Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 860-8555, Japan.
Journal of the American Chemical Society
|April 25, 2025
Resumen
Los nuevos catalizadores no platino que utilizan un complejo cobalto-nitrógeno (Co-14MR) muestran una mayor reducción de oxígeno y reacciones de evolución de hidrógeno. El tratamiento térmico mejora el rendimiento y la durabilidad de las pilas de combustible y la división del agua.
Área de la Ciencia:
- La electroquímica
- Ciencias de los materiales
- Catálisis
Sus antecedentes:
- El desarrollo de catalizadores de metales del grupo no platino (no PGM) es crucial para las reacciones electroquímicas eficientes.
- Las pilas de combustible de membrana de intercambio de protones (PEMFC) y la escisión de agua requieren catalizadores robustos para la reacción de reducción de oxígeno (ORR) y la reacción de evolución de hidrógeno (HER) en condiciones ácidas.
Objetivo del estudio:
- Desarrollar y caracterizar nuevos catalizadores no PGM basados en un complejo cobalto-nitrógeno con un ligando hexaazamacrocíclico de 14 miembros (Co-14MR).
- Evaluar la actividad catalítica y la durabilidad del Co-14MR/C para la ORR y la HER en medios ácidos.
- Investigar el efecto del tratamiento térmico en la estructura y el rendimiento del catalizador.
Principales métodos:
- Síntesis del catalizador Co-14MR (Co-14MR/C) con soporte de carbono.
- Pruebas electroquímicas para la actividad y durabilidad de ORR y HER.
- Tratamiento térmico del Co-14MR/C a 600 °C.
- Cálculos de la teoría funcional de la densidad (DFT) para comprender las relaciones estructura-actividad.
- Análisis estructural (por ejemplo, longitudes de enlace, distorsión).
Principales resultados:
- El Co-14MR/C exhibió una ORR y una actividad de HER superiores en comparación con un catalizador de Coftalocianina convencional (CoPc/C).
- El tratamiento térmico de Co-14MR/C mejoró significativamente su rendimiento catalítico.
- Los cálculos DFT revelaron que el tratamiento térmico optimizó las energías de adsorción intermedias para mejorar la ORR y la cinética HER.
- Co-14MR/ C demostró una mayor durabilidad tanto en ORR como en HER en comparación con CoPc/ C y Fe-14MR/ C.
- Los enlaces cortos de CoN y la mínima distorsión del sitio activo de CoN4 contribuyeron a la alta durabilidad.
Conclusiones:
- La estructura de Co-14MR representa un diseño prometedor para electrocatalizadores avanzados sin PGM.
- El Co-14MR/C tratado térmicamente ofrece una alternativa viable a los catalizadores a base de platino para las PEMFC y las aplicaciones de escisión de agua.
- La comprensión de los factores estructurales que influyen en la actividad catalítica y la durabilidad es clave para el desarrollo futuro del catalizador.
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