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Cambios de forma de las nanopartículas Rh soportadas durante los ciclos de oxidación y reducción
P Nolte1, A Stierle, N Y Jin-Phillipp
1Max-Planck-Institut für Metallforschung, Heisenbergstrasse 3, D-70569 Stuttgart, Germany.
Science (New York, N.Y.)
|September 20, 2008
Resumen
Las nanopartículas de rodio cambian de forma durante la oxidación, una transformación invertida por el monóxido de carbono. Este descubrimiento ofrece información sobre el comportamiento de las nanopartículas durante las reacciones catalíticas.
Área de la Ciencia:
- La catálisis heterogénea.
- Ciencia de los materiales ciencia de los materiales.
- Química de las superficies.
Sus antecedentes:
- Comprender los cambios de forma de las nanopartículas durante las reacciones catalíticas es crucial para el conocimiento fundamental de la catálisis.
- Los ciclos de oxidación y reducción tienen un impacto significativo en la estructura y la reactividad de las nanopartículas.
Objetivo del estudio:
- Para investigar la transformación de la forma inducida por el oxígeno de las nanopartículas de rodio en sustratos de óxido de magnesio.
- Explorar el mecanismo detrás de este cambio de forma y su reversión.
Principales métodos:
- Difracción de rayos X de alta resolución in situ.
- Microscopía de electrones de transmisión.
- El análisis de Wulff.
Principales resultados:
- Las nanopartículas de rodio sufren una transformación de forma en el óxido de magnesio (001) debido a la exposición al oxígeno.
- La exposición al monóxido de carbono a 600 Kelvin invierte esta transformación de la forma.
- El fenómeno es impulsado por la formación de una capa de óxido superficial (oxígeno-rodío-oxígeno) en las nanofacetas de rodio.
Conclusiones:
- El estudio proporciona una visión experimental de la dinámica de las nanopartículas durante los ciclos catalíticos.
- Esta comprensión es vital para diseñar y desarrollar catalizadores heterogéneos avanzados con mejor rendimiento.
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