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Hidrogenación endérgica en condiciones ambientales utilizando un reactor de membrana electroquímica
Camden Hunt1,2, Aiko Kurimoto1, Georgia Wood1
1Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, Canada V6T 1Z1.
Journal of the American Chemical Society
|June 21, 2023
Resumen
La carga de hidrógeno en los reactores electroquímicos de membrana de paladio aumenta con la densidad de corriente y la concentración de electrolitos. Este estudio cuantifica la carga de hidrógeno y su impacto en la fuerza motriz de las reacciones de hidrogenación.
Área de la Ciencia:
- La electroquímica
- Ciencias de los materiales
- Ingeniería Química
Sus antecedentes:
- Los reactores electroquímicos de membrana de paladio (ePMR) son cruciales para varias transformaciones químicas.
- La comprensión de la carga de hidrógeno (x) es clave para optimizar el rendimiento ePMR y la fuerza motriz termodinámica.
- Los estudios anteriores carecían de una cuantificación detallada de la carga de hidrógeno en condiciones electroquímicas variables.
Objetivo del estudio:
- Determinar cómo se correlaciona la carga de hidrógeno (x) en las ePMR con parámetros electroquímicos como la densidad de corriente y la concentración de electrolitos.
- Para aclarar la influencia de la carga de hidrógeno (x) en la fuerza motriz termodinámica de las ePMR.
- Demostrar la capacidad de las ePMR para impulsar reacciones de hidrogenación endergónica.
Principales métodos:
- Se ha medido la fugacidad del hidrógeno (P) desorbido por las membranas de paladio-hidrógeno.
- La fugacidad relacionada (P) con las isotermas de composición por presión para determinar la carga de hidrógeno (x).
- Mediciones validadas mediante estudios electroquímicos de permeación de hidrógeno y modelado por análisis de elementos finitos (FEA).
- Capacidad de ePMR demostrada empíricamente mediante la reducción del dióxido de carbono para formar.
Principales resultados:
- La carga de hidrógeno (x) aumenta con la densidad de corriente aplicada y la concentración de electrolitos.
- Se observó una meseta en la carga de hidrógeno (x) de aproximadamente 0,92 en 1,0 M H2SO4 a -200 mA·cm-2.
- Las mediciones se validaron experimentalmente y computacionalmente, acordando propiedades dependientes de x.
- Se determinó la energía libre de la formación de aleación de paladio-hidrógeno (ΔG(x) PdH, alcanzando un máximo de 11 kJ·mol-1.
Conclusiones:
- Las condiciones electroquímicas influyen significativamente en la carga de hidrógeno en las ePMR.
- La fuerza motriz termodinámica determinada (ΔG(x) PdH) indica que las ePMR pueden impulsar reacciones endergónicas.
- El éxito de la reducción de CO2 a formato demuestra la aplicación práctica de las ePMR para la síntesis química sostenible.
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