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Reconocimiento de los efectos inducidos por el agua hacia una interacción mejorada entre catalizador y reactivo en la
Qianbing Wei1, Chang Yu1, Xuedan Song1
1State Key Lab of Fine Chemicals, School of Chemical Engineering, Liaoning Key Lab for Energy Materials and Chemical Engineering, Dalian University of Technology, Dalian, China.
Journal of the American Chemical Society
|April 8, 2021
Resumen
El agua aumenta la actividad catalítica en las emulsiones de Pickering para la oxidación del alcohol. Este estudio aclara el papel del agua, revelando su participación y efectos positivos en la oxidación del alcohol bencílico sobre un catalizador Pd/MgAl-LDO.
Área de la Ciencia:
- Catálisis
- Ciencias de los materiales
- Química Física
Sus antecedentes:
- Las emulsiones de Pickering ofrecen microambientes únicos para la catálisis.
- El papel específico de los disolventes, en particular el agua, en estos sistemas sigue sin estar claro.
- Comprender los efectos del disolvente es crucial para optimizar las reacciones catalíticas.
Objetivo del estudio:
- Aclarar el papel intrínseco del agua en la promoción de la oxidación del alcohol dentro de las emulsiones de Pickering.
- Investigar el mecanismo de la actividad promovida por el agua utilizando alcohol bencílico como reactivo modelo.
- Demostrar la aplicabilidad general de los efectos de promoción del agua en la catálisis heterogénea.
Principales métodos:
- Se utilizó la oxidación de alcohol bencílico sobre un catalizador Pd/MgAl-LDO en emulsiones de Pickering.
- Se emplearon efectos de isótopos cinéticos para confirmar la participación del agua.
- Adsorción por pulso de vapor de agua aplicado y desorción programada por temperatura para identificar la promoción de agua.
- Se ha investigado la adsorción del reactivo en la interfaz agua-catalizador mediante espectroscopia de Raman casi in situ.
Principales resultados:
- La presencia de agua influye significativamente en las tasas de reacción, con una reactividad variable basada en la proporción de agua.
- Los efectos cinéticos del isótopo confirmaron la participación directa del agua y el impacto beneficioso en la oxidación del alcohol bencílico.
- Los estudios de adsorción y desorción de vapor de agua identificaron efectos específicos de promoción del agua.
- La espectroscopia Raman casi in situ reveló comportamientos de adsorción en la interfaz agua-Pd/MgAl-LDO.
- Se propuso un mecanismo de Langmuir-Hinshelwood para la oxidación de alcohol promovida por agua.
Conclusiones:
- El agua actúa como promotor en las reacciones de oxidación del alcohol dentro de las emulsiones de Pickering.
- El estudio proporciona una comprensión mecanicista del papel del agua en la interfaz.
- Los efectos de promoción del agua son ampliamente aplicables en diferentes soportes y sustratos de catalizadores, mejorando el rendimiento catalítico.
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