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Sondaje directo de la reacción de evolución del oxígeno en superpartículas nanocristalinas únicas con estructuras
Xiaoxi Lu1, Mingzhong Li2, Yu Peng1
1State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620, China.
Journal of the American Chemical Society
|October 6, 2021
Resumen
Ahora es posible medir directamente la actividad electrocatalítica de las superredes de nanocristales individuales. Este estudio revela cómo el tamaño y la composición del óxido de níquel y las superpartículas de oro afectan las reacciones de evolución del oxígeno.
Área de la Ciencia:
- Ciencias de los materiales
- La electroquímica
- Nanotecnología
Sus antecedentes:
- Las superredes de nanocristales autoensambladas poseen propiedades sintonizables para aplicaciones de catálisis y energía.
- La evaluación de la actividad electrocatalítica intrínseca de estos materiales es difícil debido al promedio de conjunto.
Objetivo del estudio:
- Para medir directamente la actividad de la reacción de evolución del oxígeno (OER) de las superredes nanocristalinas individuales.
- Para establecer la relación estructura-actividad en el NiFe2O4 sintonizable y las superrías Au.
Principales métodos:
- Se utilizó la microscopía de células electroquímicas de barrido (SECCM) para mediciones electroquímicas directas a nivel de una sola partícula.
- Se utiliza el microscopio electrónico de barrido (SEM) para el análisis estructural correlacionado.
- Las superredes investigadas están compuestas por nanocristales de óxido de hierro de níquel (NiFe2O4) y oro (Au).
Principales resultados:
- Frecuencias de rotación determinadas (TOF) para superpartículas individuales de NiFe2O4 que van desde 0,2 hasta 11 s^-1 a 1,92 V frente a RHE.
- Actividad dependiente del tamaño observada para las superpartículas de NiFe2O4 menores de aproximadamente 800 nm.
- Se encontró que la incorporación de nanocristales Au aumentó el TOF en aproximadamente 6 veces, con una actividad que se estabilizó con un mayor contenido de Au.
Conclusiones:
- Demostró el primer estudio electroquímico de una sola entidad en superredes nanocristalinas individuales.
- Relaciones intrínsecas de estructura-actividad desentrañadas no accesibles a través de mediciones convencionales de conjunto.
- Proporcionó una nueva metodología para caracterizar las propiedades electrocatalíticas de los nanomateriales.
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