Monitoring charge transfer at polarisable liquid/liquid interfaces employing time-resolved Raman spectroelectrochemistry

• A new four electrode cell for Raman spectroelectrochemistry at ITIES is developed.
• Real-time Raman spectra during ion and electron transfer at ITIES are obtained.
• The aqueous side of the interface or the organic side can be sampled.
• A clear correlation between spectroscopic and electrochemical responses is observed.

In-situ Raman spectroscopy is implemented for the first time to monitor dynamic charge transfer processes at polarisable interfaces between two immiscible electrolyte solutions (ITIES) in real time. A custom-designed new electrochemical cell is described which allows probing the Raman signals of ferroin ions as a function of the potential applied across the water|1,2-dichlorobenzene (DCB) interface. This approach is also used for investigating the heterogeneous electron transfer reaction involving dimethylferrocene in DCB and potassium hexacyanoferrate (II/III) in the aqueous phase. The evolution of the Raman signals during potentiodynamic measurements is recorded in real-time with a resolution of a few seconds.