Electrochemical Tip-Enhanced Raman Spectroscopy for the Elucidation of Complex Electrochemical Reactions

Area of Science:

• Nanoscience
• Electrochemistry
• Spectroscopy

Background:

• Tip-enhanced Raman spectroscopy (TERS) is a powerful nanospectroscopy technique.
• In situ/operando implementation of TERS in liquid phase under electrochemical polarization (EC-TERS) presents significant challenges.
• Investigating nanoscale electrochemical processes in real-time requires advanced techniques.

Purpose of the Study:

• To overcome challenges in EC-TERS implementation for liquid-phase electrochemical studies.
• To investigate the complex reduction mechanism of a thiolated nitrobenzene derivative (4-NBM) at the nanoscale.
• To elucidate reaction pathways not easily detectable by electrochemical methods alone.

Main Methods:

• Development and application of electrochemical scanning tunneling microscopy tip-enhanced Raman spectroscopy (EC-STM-TERS).
• Analysis of 4-NBM reduction under specific electrochemical conditions.
• Spectroscopic investigation over wide potential windows.

Main Results:

• Successfully applied EC-TERS to study a complex electrochemical system (4-NBM).
• Identified specific conditions limiting the full electrochemical reduction of 4-NBM.
• Provided evidence for a bimolecular electrochemical reaction pathway, difficult to discern from electrochemical data alone.

Conclusions:

• EC-TERS is a viable technique for detailed nanoscale electrochemical studies.
• A novel bimolecular electrochemical reaction pathway for 4-NBM was proposed.
• The study enhances understanding of complex, potentially pH-dependent, multistep reaction mechanisms in electrochemical systems.