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Catálisis de sulfuro sin sitios coordinadamente insaturados: hidrogenación, isomerización cis-trans y mezcla de H2/D2
Thomas Drescher1, Felix Niefind, Wolfgang Bensch
1Laboratory of Industrial Chemistry, Ruhr University Bochum, P.O. Box 102148, 44780 Bochum, Germany.
Journal of the American Chemical Society
|November 7, 2012
Resumen
El disulfuro de molibdeno (MoS2) y el disulfuro de tungsteno (WS2) catalizan reacciones en superficies saturadas de sulfuro, refutando las teorías que requieren insaturación coordinada para la catálisis. Esto apoya nuevos modelos teóricos con evidencia experimental.
Área de la Ciencia:
- La catálisis heterogénea.
- Ciencias de la superficie Ciencias de la superficie.
- Química de los materiales química de los materiales.
Sus antecedentes:
- Las teorías clásicas de catálisis proponen que la insaturación coordinativa es esencial para las reacciones superficiales.
- Estudios previos teóricos y de modelos de catalizadores sugirieron mecanismos alternativos para la catálisis.
- Faltaba la validación experimental en sistemas catalíticos reales.
Objetivo del estudio:
- Investigar experimentalmente la actividad catalítica de MoS2 y WS2 bajo condiciones de superficie específicas.
- Desafiar el paradigma establecido de la insaturación coordinada en la catálisis heterogénea.
- Proporcionar apoyo empírico a las teorías catalíticas emergentes.
Principales métodos:
- Se utilizaron reacciones de prueba simples: hidrogenación de eteno, isomerización cis-trans de 2-buteno y mezcla de H2/D2.
- Empleó espectroscopia de fotoelectrones de rayos X (XPS) para analizar los estados de la superficie.
- Centrado en los catalizadores MoS2 y WS2 en estados de superficie que no absorben químicamente el oxígeno.
Principales resultados:
- MoS2 y WS2 demostraron actividad catalítica en superficies saturadas con especies de sulfuro.
- Estas superficies activas se caracterizaban por una falta de oxígeno por quimiosorbción.
- El análisis XPS confirmó la saturación de sulfuro de los sitios catalíticamente activos.
Conclusiones:
- La catálisis puede ocurrir en superficies saturadas coordinativamente, lo que contradice las teorías clásicas.
- Los hallazgos validan experimentalmente nuevos conceptos de catálisis desarrollados a través de cálculos teóricos y estudios de modelos.
- Esta investigación abre nuevas vías para comprender y diseñar catalizadores basados en materiales de sulfuro.
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