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Producción de hidrógeno fotocatalítico con un complejo molecular de cobalto en soluciones acuosas alcalinas

Ping Wang¹, Nghia Le², John Daniel McCool¹

¹Department of Chemistry, University of Memphis, Memphis, Tennessee 38152, United States.

Journal of the American Chemical Society

|March 26, 2024

Resumen

Los investigadores desarrollaron un nuevo catalizador de cobalto para una reacción eficiente de evolución del hidrógeno (HER) en soluciones alcalinas. Este avance es crucial para el desarrollo de sistemas sostenibles de división de agua impulsados por energía solar.

Área de la Ciencia:

Química inorgánica
Catálisis
La fotoquímica
Ciencias de los materiales

Sus antecedentes:

La división del agua requiere catalizadores eficientes para las semirreacciones de oxidación y reducción.
Las soluciones alcalinas son termodinámicamente favorables para la oxidación del agua, lo que requiere catalizadores de reacción de evolución de hidrógeno (HER) compatibles.
El HER impulsado por luz visible en soluciones acuosas puramente alcalinas utilizando complejos metálicos moleculares está poco explorado.

Objetivo del estudio:

Desarrollar un catalizador de metal molecular para el HER impulsado por luz visible en soluciones acuosas puramente alcalinas.
Investigar el mecanismo catalítico y las relaciones estructura-función del nuevo complejo de cobalto.

Principales métodos:

Síntesis y caracterización de un nuevo complejo de cobalto con un ligando de tetrapiridilamina.
Experimentos de reacción fotocatalítica de evolución del hidrógeno (HER) en soluciones acuosas a pH 9,0.
Cálculos de la teoría funcional de la densidad (DFT) para dilucidar el mecanismo de reacción.

Principales resultados:

El complejo de cobalto demostró una alta actividad catalítica para el HER fotolítico con un número de rotación de hasta 218.000.
Los cálculos de DFT propusieron una vía modificada de transferencia de electrones-transferencia de protones-transferencia de electrones-transferencia de protones (mod-ECEC).
Se demostró que las modificaciones sutiles del andamio de ligandos afectan significativamente el rendimiento catalítico.

Conclusiones:

El complejo de cobalto desarrollado es un catalizador molecular altamente eficaz para el HER impulsado por luz visible en medios acuosos alcalinos.
Este trabajo avanza en el diseño de catalizadores moleculares para desafiar las condiciones alcalinas en la división del agua impulsada por el sol.
Comprender las relaciones estructura-función es clave para optimizar el diseño del catalizador molecular.

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