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La unión selectiva de O2 sobre N2 en un marco metálico-orgánico redox-activo con hierro abierto (II) sitios de
Eric D Bloch1, Leslie J Murray, Wendy L Queen
1Department of Chemistry, University of California, Berkeley, California 94720, USA.
Journal of the American Chemical Society
|August 12, 2011
Resumen
Este estudio presenta un nuevo marco metálico-orgánico, Fe2 dobdc, capaz de adsorber selectivamente el oxígeno. Este material es prometedor para la separación eficiente del aire a temperaturas más altas.
Área de la Ciencia:
- Ciencia de los materiales Ciencia de los materiales.
- Química Inorgánica La Química Inorgánica es la química inorgánica.
- Ciencia de la Separación Ciencia de la Separación
Sus antecedentes:
- Los marcos metálico-orgánicos (MOF) ofrecen propiedades sintonizables para la adsorción de gases.
- Las estructuras de tipo MOF-74/CPO-27 son conocidas por sus grandes superficies y poros en forma de canal.
- La separación eficiente del oxígeno del aire es crucial para varias aplicaciones industriales.
Objetivo del estudio:
- Para sintetizar y caracterizar un nuevo marco metálico-orgánico Fe.
- Investigar las propiedades de adsorción de gas del marco desolvado, en particular para O(2) y N(2).
- Para explorar el potencial de Fe (((2) (((dobdc) para aplicaciones de separación de aire.
Principales métodos:
- Síntesis sin aire de Fe(2)(dobdc) ·4DMF utilizando FeCl(2) y H(4) dobdc.
- Desolución para obtener el material poroso Fe (((2) ((dobdc).
- La medición de isotermas de adsorción de gas en 298 K y 211 K.
- Análisis espectroscópico (Mössbauer, IR) y difracción de neutrones en polvo para la caracterización estructural y electrónica.
- Simulaciones de la Teoría de la Solución Adsorbida Ideal (IAST) para curvas de avance.
Principales resultados:
- Fe(2)(dobdc) fue sintetizado como un análogo de MOF-74/CPO-27 con una superficie BET de 1360 m(2)/g.
- El material exhibe adsorción selectiva de O2 sobre N2 con alta capacidad (9,3 wt% a 298 K, 18,2 wt% a 211 K).
- Los datos espectroscópicos y de difracción indican la transferencia de carga entre Fe (II) y O (II), formando Fe (III) y O (II) (II) -) después de la oxidación a temperatura ambiente.
- Se identificaron modos de unión O2 como simétricos de lado a lado a baja temperatura y se deslizaban de lado cuando se oxidaban.
Conclusiones:
- Fe2 es un material altamente efectivo para la captura selectiva de oxígeno.
- Los mecanismos de adsorción y transferencia de carga reversibles observados O(2) son clave para su rendimiento.
- Las simulaciones de IAST sugieren que Fe2 es un candidato prometedor para la separación de aire industrial a temperaturas elevadas.
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