Decoding Double Layer Dynamics for CO 2 ${\rm CO}_2$ Electroreduction over Cu.

Area of Science:

• Electrochemistry
• Surface Science
• Spectroscopy

Background:

• The electric double layer (EDL) significantly influences electrocatalytic reactions like the carbon dioxide reduction reaction (CO2RR).
• Direct spectroscopic evidence linking EDL structure dynamics to CO2RR kinetics has been lacking.

Purpose of the Study:

• To develop a novel spectroscopic method for probing the dynamic nature of the EDL.
• To elucidate the relationship between EDL restructuring and CO2RR activity.

Main Methods:

• Introduction of Dynamic Response Spectroscopy (DRS) to analyze time-resolved infrared spectral data.
• Application of DRS to study EDL features (compact and diffuse layers) based on time-variance profiles.
• Investigation of EDL behavior under sequential potential steps during CO2RR.

Main Results:

• EDL equilibration occurs through discrete restructuring events, not continuous changes.
• Spectroscopic evidence shows EDL reorganizations correlate with CO2 adsorption and conversion to CO.
• CO2 saturation, compared to Ar, leads to increased water reorientation in the diffuse EDL.

Conclusions:

• DRS provides unprecedented insights into the dynamic EDL structure and its role in electrocatalysis.
• Understanding EDL dynamics is crucial for optimizing electrochemical systems like CO2RR.
• This work establishes a new paradigm for studying interfacial phenomena in electrocatalysis.