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Sitios asimétricos en el ZnZrO catalizador para promover la formación de formato y la transformación en CO2
Zhendong Feng1,2, Chizhou Tang1,2, Pengfei Zhang1
1State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
Journal of the American Chemical Society
|June 1, 2023
Resumen
Las especies de formato son intermedios clave en la hidrogenación de CO2 al metanol. Este estudio revela que los sitios asimétricos de Zn-O-Zr en los catalizadores de ZnZrO facilitan la formación y conversión de formatos, mejorando la producción de metanol.
Área de la Ciencia:
- Catálisis
- Química de las superficies
- Ciencias de los materiales
Sus antecedentes:
- El papel del formato en la hidrogenación de CO2 al metanol sigue siendo objeto de debate, con pruebas directas limitadas para su vía de reacción.
- El formato se observa con frecuencia, pero no se ha establecido su papel definitivo como intermediario de reacción para la síntesis de metanol.
Objetivo del estudio:
- Investigar la formación y conversión de especies de formato durante la hidrogenación con CO2 sobre catalizadores de solución sólida de ZnZrO.
- Elucidar el mecanismo de reacción e identificar los sitios activos responsables de la producción de metanol.
Principales métodos:
- Espectroscopia de masa por transformación de Fourier de reflectancia difusa in situ/operando (DRIFTS-MS) para el monitoreo de las reacciones en tiempo real.
- Cálculos de la teoría funcional de la densidad (DFT) para comprender las vías de reacción y la estabilización intermedia.
- Utilizando catalizadores de solución sólida de ZnZrO con sitios activos asimétricos definidos.
Principales resultados:
- El carbonato de bidentato, formado por adsorción de CO2, se hidrogena para formar en sitios asimétricos de Zn-O-Zr.
- Los sitios Zn activan H2, mientras que los sitios Zr estabilizan los intermedios de reacción, promoviendo la formación y conversión de formato.
- Los sitios asimétricos de Zn-O-Zr son cruciales tanto para la generación de formato como para su posterior transformación.
Conclusiones:
- El excelente rendimiento de los catalizadores de ZnZrO en la formación de metanol se atribuye a los sitios asimétricos de Zn y Zr.
- Estos sitios asimétricos promueven la escisión heterolítica de H2, facilitando la vía de reacción a través de los intermediarios formados.
- El estudio proporciona pruebas definitivas de la reacción de las especies de formato en la hidrogenación de CO2 al metanol sobre los catalizadores de ZnZrO.
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