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Evolución de hidrógeno electrocatalítico a bajos sobrepotenciales por complejos de glyoxima y tetraimina
Xile Hu1, Bruce S Brunschwig, Jonas C Peters
1Arnold and Mabel Beckman Laboratories of Chemical Synthesis and the Beckman Institute, Division of Chemistry and Chemical Engineering, California Institute of Technology, MC 127-72, Pasadena, California 91125, USA.
Journal of the American Chemical Society
|July 3, 2007
Resumen
Los complejos de cobalto con los ligandos diglioxima y tetraeno-N4 catalizan eficientemente la evolución del hidrógeno electroquímicamente. Potenciales redox más bajos de Co (II/I) se correlacionan con una mayor actividad y estabilidad de producción de H2.
Área de la Ciencia:
- Química Inorgánica La Química Inorgánica es la química inorgánica.
- La electroquímica es electroquímica.
- La catálisis de la catálisis.
Sus antecedentes:
- Los complejos de cobalto se investigan por su potencial en la evolución del hidrógeno electrocatalítico.
- Comprender la relación entre los potenciales redox y la actividad catalítica es crucial para diseñar catalizadores eficientes.
Objetivo del estudio:
- Para sintetizar y caracterizar complejos de cobalto con diglioxima y tetraeno-N4 ligandos.
- Evaluar la actividad electrocatalítica de estos complejos para la evolución del hidrógeno en el acetonitrilo.
- Para investigar la influencia de la estructura del ligando y las propiedades redox en el rendimiento catalítico y la estabilidad.
Principales métodos:
- Síntesis y caracterización de los complejos cobalto-digloxima y cobalto-tetraeno-N4.
- Mediciones electrocatalíticas de la evolución del hidrógeno utilizando voltametría cíclica y electrólisis a granel.
- Análisis electroquímico que incluye la determinación del potencial redox.
- Simulaciones digitales para aclarar el mecanismo catalítico.
Principales resultados:
- Los complejos de cobalto con diglioxima y tetraeno-N4 ligandos exhiben evolución electrocatalítica H2 entre -0.55 V y -0.20 V vs SCE.
- Los complejos con más potenciales redox positivos de Co (II/I) mostraron una menor actividad de producción de H2.
- Se confirmó la evolución catalítica de H2 para Co(dmgBF2) 2 ((CH3CN) 2 , Co(dpgBF2) 2 ((CH3CN) 2 , [Co(TimMe) Br 2 ] Br y [Co(TimMe) ((CH3CN) 2 ] ((BPh4) 3 con altos números de facturación y rendimientos faradaicos.
- Co ((dmgBF2) 2 ((CH3CN) 2 demostró el más pequeño sobrepotencial (40 mV) y también podría oxidar H2.
- La evidencia de los intermediarios de hidruro de Co (III) se observó a través de la voltametría cíclica.
Conclusiones:
- Los complejos de cobalto, en particular el Co ((dmgBF2) 2 ((CH3CN) 2), son electrocatalizadores efectivos para la evolución del H2.
- El diseño de los ligandos y las propiedades redox tienen un impacto significativo en la eficiencia y estabilidad catalítica.
- El mecanismo catalítico probablemente involucra intermediarios de hidróxido de Co (III).
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