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Más allá de los hidrógenos metálicos: Evolución de hidrógeno electrocatalítico centrada en ligandos sin metales de
Andrew Z Haddad1, Brady D Garabato1, Pawel M Kozlowski1,2
1University of Louisville , Department of Chemistry, 2320 South Brook Street, Louisville, Kentucky 40292, United States.
Journal of the American Chemical Society
|June 22, 2016
Resumen
Los investigadores desarrollaron una nueva vía libre de metales para la evolución y oxidación del hidrógeno utilizando ligandos de tiosemicarbazona. Estos catalizadores alcanzan frecuencias de rotación récord (TOF) sin depender de los intermedios de hidrógeno metálico.
Área de la Ciencia:
- La electroquímica
- Catálisis
- Ciencias de los materiales
Sus antecedentes:
- La evolución y la oxidación del hidrógeno electrocatalítico homogéneo son cruciales para las tecnologías de energía renovable.
- Los catalizadores actuales a menudo se basan en metales de transición e intermedios de hidrógeno metálico, lo que limita su sostenibilidad y eficiencia.
- El desarrollo de alternativas libres de metales o abundantes en tierra es un desafío importante en la catálisis.
Objetivo del estudio:
- Introducir un nuevo sistema catalítico libre de metales para la evolución y la oxidación del hidrógeno.
- Demostrar la eficacia de los ligandos tiosemicarbazone redox-activos y su complejo de zinc como catalizadores.
- Para aclarar el mecanismo de catálisis, en particular la ausencia de metales hidruro intermedios.
Principales métodos:
- Síntesis electroquímica y caracterización del diacetyl-bis ((N-4-metil-3-tiosemicarbazone) y su complejo de zinc.
- Evaluación del rendimiento electrocatalítico para la evolución y la oxidación de H2.
- Estudios mecánicos mediante técnicas electroquímicas y cálculos de la teoría funcional de la densidad (DFT).
Principales resultados:
- El ligando tiosemicarbazone y su complejo de zinc alcanzaron las frecuencias de rotación más altas reportadas para la evolución homogénea centrada en el ligando H2 (1320 y 1170 s-1).
- El complejo de zinc exhibió un alto TOF para la oxidación de H2 (72 s-1), entre los mejores para catalizadores homogéneos.
- La catálisis procede a través de la transferencia de protones y electrones centrada en el ligando, distinta de las vías tradicionales de hidruro de metal.
Conclusiones:
- Se ha descubierto una nueva vía mecanicista para la evolución y oxidación de H2 electrocatalítico homogéneo.
- Los sistemas basados en tiosemicarbazona ofrecen una alternativa prometedora sin metales y sin metales de transición para la catálisis de H2.
- Este trabajo abre nuevas vías para el diseño de electrocatalizadores sostenibles independientes de los intermedios de hidrógeno metálico.
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