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Situaciones diméricas en superficie de Mn-Mn dictan la actividad de hidrogenación de CO y la selectividad sobre los

Ke-Xiang Zhang¹, Zhi-Pan Liu^1,2

¹Collaborative Innovation Center of Chemistry for Energy Material, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Key Laboratory of Computational Physical Science, Department of Chemistry, Fudan University, Shanghai 200433, China.

Journal of the American Chemical Society

|September 19, 2024

Resumen

Los investigadores identificaron el sitio activo para la producción de etanol a partir del gas de síntesis utilizando el aprendizaje automático. Los sitios diméricos de manganeso y manganeso en los catalizadores de rodio mejoran significativamente la formación de oxígeno C2, aumentando la eficiencia y la selectividad para aplicaciones industriales.

Área de la Ciencia:

Catálisis
Ciencias de los materiales
Química computacional

Sus antecedentes:

La producción de etanol a partir del gas de síntesis es crucial para la energía sostenible.
Los catalizadores de rodio promovidos por manganeso (MnRh) son prometedores para una alta selectividad de oxígeno C2.
El sitio activo en los catalizadores de MnRh sigue siendo poco conocido.

Objetivo del estudio:

Identificar las fases de Mn más estables en las superficies Rh en condiciones de reacción.
Para dilucidar la estructura atómica del sitio activo para la formación de oxigenado C2.
Comprender el mecanismo de reacción y optimizar la producción de etanol.

Principales métodos:

Optimización global de aprendizaje automático a gran escala para explorar las estructuras de Mn en superficies Rh.
Exploración del estado de transición basada en el aprendizaje automático para mapear la red de reacción.
Simulaciones microcinéticas para determinar las velocidades de reacción y la selectividad.

Principales resultados:

El manganeso ocupa preferentemente sitios subterráneos en Rh y forma aleaciones superficiales con adsorbados oxidativos.
El sitio dimérico Mn-Mn en los bordes del paso monoatómico fue identificado como el verdadero sitio activo.
El sitio dimérico Mn-Mn exhibe una frecuencia de rotación 10 ^ 7 veces mayor que los sitios Rh puros, con una selectividad de C2 del 52% a 523 K.

Conclusiones:

Los sitios diméricos Mn-Mn son esenciales para la escisión eficiente de enlaces C-O y la hidrogenación de los intermedios C2.
Estos sitios mejoran dramáticamente la selectividad y la tasa de producción de etanol en comparación con el Rh puro.
El estudio aclara el sitio activo, allanando el camino para mejorar el diseño del catalizador para la conversión de gas de síntesis.

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