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Efectos mecánicos intrínsecos en la activación de los catalizadores de carbono

Bowen Liu^1,2, Shuaishuai Xu¹, Yang Gao¹

¹CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology (NCNST), Beijing 100190, China.

Journal of the American Chemical Society

|January 23, 2025

Resumen

El esfuerzo mecánico mejora significativamente los catalizadores libres de metales basados en carbono (C-MFC) para la reacción de reducción de oxígeno (ORR). La aplicación de tensión de tracción al carbono grafítico defectuoso aumenta la actividad ORR al optimizar la adsorción intermedia, allanando el camino para la mecanoelectrocatálisis.

Área de la Ciencia:

Ciencias de los materiales
La electroquímica
Catálisis

Sus antecedentes:

Los catalizadores sin metales basados en carbono (C-MFC) son alternativas prometedoras a los catalizadores de metales nobles.
El impacto de la tensión mecánica en las C-MFC sigue siendo poco explorado debido a la complejidad de otros factores estructurales.
La comprensión de los efectos de la tensión es crucial para el avance de las aplicaciones de C-MFC.

Objetivo del estudio:

Investigar los efectos mecánicos de la tensión en los catalizadores de carbono grafítico.
Establecer una correlación entre la tensión superficial y la actividad catalítica para la reacción de reducción de oxígeno (ORR).
Aclarar los principios fundamentales de los efectos de la tensión en las C-MFC.

Principales métodos:

Desarrollo de una plataforma para la aplicación de esfuerzo continuo al grafito pirolítico altamente orientado (HOPG).
Recopilación simultánea de señales electroquímicas bajo tensión aplicada.
Simulaciones de la teoría funcional de la densidad (DFT) para comprender las modificaciones de los defectos inducidas por la tensión.

Principales resultados:

La tensión tensional no activó los sitios de carbono prístinos en el plano o en el borde en HOPG.
Se observó una mejora significativa y repetible en la actividad catalítica ORR en presencia de defectos en el plano.
Se logró una mejora de ~35.0% en la densidad de corriente ORR con una tensión de ~0.6% en el HOPG defectuoso.
Las simulaciones DFT identificaron los defectos de Stone-Wales como sitios clave para la optimización mediada por tensión de la adsorción intermedia.

Conclusiones:

La tensión superficial puede modular significativamente la actividad catalítica del carbono grafítico defectuoso para ORR.
La ingeniería de deformación de defectos ofrece una nueva vía para desarrollar C-MFC de alto rendimiento.
Este estudio sienta las bases para el campo emergente de la mecanoelectrocatálisis basada en el carbono.

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