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Identificación de las superficies activas de LiCoO sintonizado electroquímicamente para la reacción de evolución del

Zhiyi Lu¹, Guangxu Chen¹, Yanbin Li¹

¹Department of Material Science and Engineering, Stanford University , Stanford, California 94305, United States.

Journal of the American Chemical Society

|April 19, 2017

Resumen

Los sitios de borde en el óxido de cobalto de litio (LCO) son clave para la catálisis de la reacción de evolución del oxígeno (OER). La deslitización electroquímica (De-LCO) mejora la actividad OER al exponer estos sitios de borde activos, no la superficie basal (0001).

Área de la Ciencia:

Ciencias de los materiales
La electroquímica
Catálisis

Sus antecedentes:

La identificación de sitios activos es crucial para el diseño de catalizadores eficientes.
El óxido de cobalto de litio en capas (LCO) es un material de interés para aplicaciones catalíticas.
La reacción de evolución del oxígeno (OER) es un proceso crítico en muchos sistemas electroquímicos.

Objetivo del estudio:

Investigar las superficies activas del LCO para el OER.
Comprender el efecto de la deslitización electroquímica (De-LCO) en la actividad OER de LCO.
Para correlacionar las predicciones teóricas con las observaciones experimentales con respecto a la actividad de la superficie LCO.

Principales métodos:

Cálculos teóricos para predecir la actividad OER en diferentes superficies de LCO.
Delitización electroquímica del LCO.
Caracterización experimental de las nanohojas de LCO y las nanopartículas para OER.
Grabación ácida de LCO para modificar las propiedades de la superficie.

Principales resultados:

La superficie estable (0001) de LCO muestra un alto sobrepotencial de OER, independiente del contenido de litio.
Se prevé que los sitios de borde, específicamente las superficies (112̅0) y (011̅2), sean altamente activos para el OER y sensibles a la (des) litiación.
Los resultados experimentales muestran una mejora insignificante de la OER para las nanohojas de LCO (superficie expuesta (0001)), pero una mejora significativa para las nanopartículas de LCO (sitios de borde expuestos).
El grabado ácido LCO para crear más sitios de borde mejoró la actividad OER, apoyando los hallazgos teóricos.

Conclusiones:

La actividad OER en el LCO se rige principalmente por los sitios de borde, no por la superficie basal (0001).
La deslitización electroquímica mejora la OER aumentando la proporción de sitios activos de Co4+ y cambiando los estados de oxígeno 2p.
La ingeniería de superficie, como la creación de más sitios de borde, es una estrategia viable para aumentar el rendimiento catalítico de LCO para OER.

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