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Determinación de la transformación y distribución reversibles de diversas especies monoatómicas Pt

Chuanmin Ding¹, Qingqing Gu², Li-Juan Yu³

¹College of Chemical Engineering and Technology, Taiyuan University of Technology, 030024 Taiyuan, China.

Journal of the American Chemical Society

|January 19, 2023

Resumen

Se cuantificaron diversas especies de un solo átomo en catalizadores. Una minoría de especies Pt en CeO2 mostró una actividad de oxidación de CO superior, destacando la importancia de las vacantes de oxígeno para el rendimiento y la transformación del catalizador.

Área de la Ciencia:

Catálisis
Ciencias de los materiales
Química de las superficies

Sus antecedentes:

Los catalizadores de un solo átomo (SAC) exhiben diversas especies de un solo átomo debido a sitios de anclaje de soporte complejos.
La distribución cuantitativa y la reactividad específica del sitio de estas especies en los SAC siguen siendo poco conocidas.
Los SACs metálicos soportados por CeO2 son ampliamente estudiados, pero carecen de descripciones cuantitativas para el análisis de la reactividad.

Objetivo del estudio:

Para revelar cuantitativamente la distribución de diversas especies de un solo átomo en las SAC de Pt/CeO2.
Investigar la reactividad específica del sitio de diferentes especies de un solo átomo en la oxidación de CO.
Comprender el papel de las vacantes de oxígeno en la transformación dinámica de las SAC.

Principales métodos:

Generación reversible de dos SAC Pt/CeO2 distintos mediante dispersiones oxidativas y no oxidativas.
Análisis cuantitativo mediante espectroscopia Raman y estudios computacionales.
Evaluación de la actividad catalítica para la oxidación de CO a baja temperatura.

Principales resultados:

Se generaron dos SACs Pt/CeO2 distintas con variadas especies Pt1Ox-Ceδ+.
La espectroscopia Raman y los estudios computacionales revelaron semi-cuantitativamente la distribución de las especies.
Las especies minoritarias de Pt1O4-Ce3+-Ov (14,2%) exhibieron la mayor reactividad a la oxidación por CO.
Las vacantes de oxígeno aumentaron sinérgicamente la actividad y facilitaron la transformación dinámica del sitio.

Conclusiones:

Elucidación de la distribución cuantitativa y la transformación dinámica de las especies monoatómicas en los SAC.
Identificación de las vacantes de oxígeno como cruciales para los efectos sinérgicos y la transformación del sitio.
Propuesta de un descriptor más intrínseco y de una medida cuantitativa de la inhomogeneidad de las CCA.

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