In situ PM-IRRAS of a glassy carbon electrode/deep eutectic solvent interface

Area of Science:

• Electrochemistry
• Materials Science
• Spectroscopy

Background:

• Deep eutectic solvents (DES) are emerging as sustainable alternatives to ionic liquids.
• Understanding electrode interfaces is crucial for electrochemical applications.
• Glassy carbon electrodes are widely used in various electrochemical systems.

Purpose of the Study:

• To investigate the interface between a choline chloride/ethylene glycol deep eutectic solvent and a glassy carbon electrode.
• To explore the surface sensitivity and potential-dependent behavior of the DES-electrode interface.
• To demonstrate the applicability of in situ spectroelectrochemical methods for studying such interfaces.

Main Methods:

• Polarization modulation reflection-absorption spectroscopy (PM-IRRAS) was employed.
• In situ spectroelectrochemical measurements were performed.
• Analysis of temporal spectral changes and potential-dependent band shifts.

Main Results:

• Slow adsorption of electrolyte molecules on the glassy carbon electrode surface was observed.
• Characteristic potential-dependent changes in band intensities and wavenumbers were detected.
• Evidence for adsorption, reduction, desorption, and reorientation of choline cations was found.

Conclusions:

• In situ spectroelectrochemical PM-IRRAS is a powerful technique for studying electrode interfaces with DES.
• The study provides insights into the interfacial structure and behavior of choline chloride/ethylene glycol DES on glassy carbon.
• Analogies were drawn to electrode/ionic liquid interfaces, suggesting general applicability.