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Imágenes directas de estructuras de superficie cristalina sintonizables de MOF MIL-101 utilizando microscopía
Xinghua Li1, Jianjian Wang2, Xin Liu3
1Physical Sciences and Engineering Division, Advanced Membranes and Porous Materials Center , King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900 , Saudi Arabia.
Journal of the American Chemical Society
|July 20, 2019
Resumen
Los aditivos influyen en la estructura superficial y la estabilidad de las estructuras orgánicas metálicas (MOF) como MIL-101. Las imágenes directas revelaron estructuras de superficie distintas y cómo el calentamiento al vacío afecta la apertura de la jaula MOF.
Área de la Ciencia:
- Ciencias de los materiales
- La cristalografía
- Nanotecnología
Sus antecedentes:
- Las estructuras orgánicas metálicas (MOF) son materiales porosos cruciales sintetizados con aditivos para controlar la cristalización.
- La comprensión de las estructuras superficiales de MOF es clave para adaptar sus propiedades a diversas aplicaciones.
Objetivo del estudio:
- Imagen directa y caracterización de las estructuras superficiales del MOF MIL-101 sintetizado con diferentes aditivos.
- Investigar el efecto del calentamiento al vacío en la estructura de la superficie y la estabilidad del marco MIL-101.
- Observar las posibles transformaciones de fase inducidas por los aditivos de síntesis.
Principales métodos:
- Microscopía electrónica de transmisión de alta resolución de baja dosis (HRTEM) para imágenes superficiales directas con resolución de células subunidad.
- Difracción de rayos X in situ (XRD) para controlar la evolución estructural durante el calentamiento al vacío.
- Síntesis de MIL-101 utilizando varios aditivos, incluido el ácido fluorhídrico.
Principales resultados:
- Identificó tres estructuras superficiales distintas en los cristales MIL-101.
- Se observó que el calentamiento al vacío abre las jaulas mesoporosas en la superficie MIL-101, con dependencia de la temperatura de los aditivos de la muestra.
- Los resultados de HRTEM e in situ XRD mostraron un buen acuerdo, lo que sugiere que los aditivos influyen en la estructura de la superficie y la estabilidad del marco.
- Se observó una transformación de fase sólido-sólido de MIL-101 a MIL-53 en muestras sintetizadas con ácido fluorhídrico.
Conclusiones:
- Los aditivos tienen un impacto significativo en la morfología superficial y la estabilidad del MOF MIL-101.
- El calentamiento al vacío puede alterar de forma controlada la porosidad de la superficie del MIL-101.
- El ácido fluorhídrico puede inducir la transformación de fase en MIL-101, destacando el papel de las condiciones de síntesis.
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