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La transformación de ceria en grupos 2D mejora la actividad catalítica

Konstantin Khivantsev¹, Hien Pham², Mark H Engelhard³

¹Pacific Northwest National Laboratory, Richland, WA, USA. Konstantin.Khivantsev@pnnl.gov.

|April 9, 2025

Resumen

Un nuevo método dispersa las nanopartículas de ceria en dominios 2D en alumina, aumentando significativamente la movilidad y el almacenamiento de oxígeno. Esto mejora la actividad catalítica para reacciones cruciales, incluso después de un envejecimiento intenso, creando catalizadores más eficientes basados en ceria.

Área de la Ciencia:

Catálisis
Ciencias de los materiales
Química de las superficies

Sus antecedentes:

Las nanopartículas de Ceria en alumina son clave en la catálisis, a menudo con metales del grupo del platino (PGM).
Las altas temperaturas pueden causar la sinterización, reduciendo la eficacia del catalizador.

Objetivo del estudio:

Investigar un nuevo tratamiento para los catalizadores ceria-alumina para mejorar su estructura y rendimiento.
Comprender la nanoestructura resultante y su impacto en las propiedades redox y la actividad catalítica.

Principales métodos:

Tratamiento reactivo de catalizadores ceria-alumina con CO, NO y vapor a 750-1000°C.
Caracterización mediante microscopía, espectroscopia de fotoelectrones de rayos X (XPS), espectroscopia de absorción de rayos X (XAS), espectroscopia infrarroja y cálculos de la teoría funcional de la densidad (DFT).

Principales resultados:

Las nanopartículas de Ceria se dispersan en dominios Ce_xO_y de alta densidad que cubren la superficie de alumina.
Mejora de la movilidad y capacidad de almacenamiento de oxígeno en los dominios 2D ceria.
Mejora de la actividad catalítica para la reducción de NO y N₂O y la oxidación de CO y NO, con o sin PGM, después de un envejecimiento intenso.

Conclusiones:

La arquitectura del catalizador desarrollada exhibe propiedades redox superiores y estabilidad en condiciones de sinterización.
Este enfoque ofrece un camino hacia catalizadores de metal-ceria de alta eficiencia para aplicaciones generales de catálisis.

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