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Conocimientos a nivel atómico sobre el mecanismo mediado por cationes en la reducción electroquímica del nitrógeno

Lin Jiang¹, Xing Zhi², Xiaowan Bai¹

¹School of Chemical Engineering, The University of Adelaide, Adelaide, SA 5005, Australia.

Journal of the American Chemical Society

|May 5, 2025

Resumen

Los cationes de potasio (K+) mejoran la reacción electroquímica de reducción de nitrógeno (NRR) para la síntesis de amoníaco verde al mejorar la adsorción de nitrógeno y la desorción de amoníaco. La optimización de la concentración de K+ y el potencial de los electrodos es clave para aumentar la eficiencia de la NRR.

Área de la Ciencia:

La electroquímica
Catálisis
Química ecológica

Sus antecedentes:

La reacción electroquímica de reducción de nitrógeno (RRN) ofrece una vía sostenible para la síntesis de amoníaco.
Los desafíos incluyen la limitada accesibilidad al N2 y la competencia de protones, lo que dificulta la selectividad de NRR.
La comprensión de los mecanismos de interfaz es crucial para optimizar el rendimiento de NRR.

Objetivo del estudio:

Investigar el papel de los cationes de potasio (K+) en la modulación de la interfaz electroquímica para la NRR.
Analizar la influencia de la concentración de K+ en la adsorción de N2, la desorción de NH3 y la cinética de la transferencia de hidrógeno (HT).
Elucidar la interacción entre la concentración de K+, el potencial de los electrodos y la selectividad del amoníaco.

Principales métodos:

Investigación computacional de entornos interfaciales bajo diferentes concentraciones de K+.
Análisis de los mecanismos de adsorción de N2, desorción de NH3 y transferencia de hidrógeno.
Modelado microkinético (MKM) para estudiar la cinética de HT y las etapas limitadoras de velocidad.

Principales resultados:

Una alta concentración de K+ mejora significativamente la adsorción de N2 y la desorción de NH3, mejorando la selectividad de la NRR.
La transferencia de hidrógeno (HT) implica la protonación (HT1) y la difusión (HT2), siendo el HT2 el que limita la velocidad.
El bajo potencial con alto K + muestra una conectividad débil y un transporte lento de protones, lo que limita la eficiencia.

Conclusiones:

Los cationes K + modulan críticamente el entorno de interfaz, aumentando el rendimiento de NRR.
La optimización del potencial del electrodo y la composición del electrolito puede mejorar el transporte de protones y la eficiencia de la NRR.
Este estudio proporciona información para mejorar la RRN a través del control de electrolitos y microambientales.

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