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Controlar el suministro de agua a una interfaz electroquímica con agentes tensioactivos
Anuj K Pennathur1, Cindy Tseng1, Noemi Salazar2
1Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States.
Journal of the American Chemical Society
|January 23, 2023
Resumen
Los tensioactivos pueden controlar la concentración de agua interfacial en las reacciones electroquímicas. Este estudio cuantifica la competencia entre el potencial aplicado y las interacciones hidrofóbicas en la conducción del comportamiento de los surfactantes, ofreciendo nuevas formas de diseñar reacciones de electrodos.
Área de la Ciencia:
- La electroquímica
- Química de las superficies
- Química Física
Sus antecedentes:
- Las reacciones electroquímicas a menudo dependen de los protones del agua.
- El agua puede competir con las reacciones deseadas, lo que requiere un bajo contenido de agua.
- El control del agua interfacial es clave para dirigir la reactividad electroquímica y la selectividad.
Objetivo del estudio:
- Investigar el papel de los tensioactivos en el control de la concentración de agua interfacial.
- Cuantificar la influencia del potencial aplicado y de las interacciones hidrofóbicas en el comportamiento del surfactante en la superficie del electrodo.
- Explorar el potencial para la ingeniería de estructuras de agua interfaciales para aplicaciones electroquímicas.
Principales métodos:
- Se empleó la electroquímica espectral del infrarrojo medio.
- En el estudio se utilizaron mezclas de agua en un disolvente orgánico (dDMSO) con un surfactante catiónico (CTAB).
- Se midió la concentración de agua interfacial bajo el potencial aplicado, variando el contenido de agua a granel.
Principales resultados:
- Una concentración modesta de CTAB alteró significativamente la concentración de agua interfacial (hasta ~35%) con el potencial aplicado.
- La acumulación/ agotamiento de agentes tensioactivos impulsado por el potencial se identificó como la causa principal de los cambios en el contenido de agua.
- Se cuantificó la competencia entre el potencial aplicado y las interacciones hidrofóbicas, revelando un "equivalente electroquímico de la unidad hidrofóbica".
Conclusiones:
- Los agentes tensioactivos modulan eficazmente la partición interfacial del agua entre el volumen y la superficie.
- El potencial aplicado y las fuerzas hidrofóbicas son factores clave del comportamiento del surfactante.
- Esta investigación proporciona una base para la ingeniería de estructuras de agua interfaciales para controlar las reacciones electroquímicas.
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