A Lens into the Cu Nanograin by In Situ Vibrational Spectroscopy

Area of Science:

• Electrochemistry
• Catalysis
• Spectroscopy

Background:

• Copper (Cu) catalysts are key for C-C coupling in electrochemical CO2 reduction (CO2R).
• Mechanistic understanding is limited by a lack of detailed information on surface adsorbate dynamics.
• In situ spectroscopic methods are needed to probe catalysts under reaction conditions.

Purpose of the Study:

• To correlate in situ surface-enhanced Raman spectroscopy (SERS) and surface-enhanced infrared absorption spectroscopy (SEIRAS) with CO2R performance on Cu nanograin catalysts.
• To develop a framework linking vibrational signatures to catalytic function and adsorbate evolution.
• To understand the role of surface species and interfacial flux in steering multicarbon product formation.

Main Methods:

• Utilized in situ SERS and SEIRAS to monitor CO2R on Cu nanograin catalysts.
• Investigated potential-dependent dynamics of surface adsorbates.
• Analyzed vibrational signatures, including CO stretch bands at different surface sites (terrace, defect/step).

Main Results:

• Identified the onset of linear CO formation below -0.45 V.
• Observed persistent adsorbed *OH/*O domains coexisting with CO2R.
• Dissected potential-dependent CO stretch bands (P1-P3) to understand coverage effects on Cu nanograins.
• Linked vibrational signatures to catalytic behavior and adsorbate coverage.

Conclusions:

• Established a diagnostic framework connecting vibrational spectroscopy to catalytic function in CO2R.
• Highlighted the intertwined roles of surface stabilization and interfacial flux in multicarbon product formation.
• Aimed to bridge the gap between observation and control for predictive CO2R selectivity.