CO₂ Reduction Catalysts on Gold Electrode Surfaces Influenced by Large Electric Fields

Area of Science:

• Electrochemistry
• Surface Science
• Catalysis

Background:

• Attaching molecular catalysts to electrodes combines molecular and heterogeneous catalysis benefits.
• Interfacial electric field effects on catalyst stability, activity, and selectivity are poorly understood.

Purpose of the Study:

• To examine interfacial electric field strength at CO2 reduction catalyst binding sites.
• To understand the influence of interfacial electric fields on catalyst configuration and CO2 binding.

Main Methods:

• Immobilization of Re and Mn bipyridine catalysts on gold electrodes.
• Sum frequency generation (SFG) spectroscopy to probe vibrational spectra.
• Density functional theory (DFT) calculations for SFG spectra and Stark tuning rates.

Main Results:

• Potential-dependent frequency shifts observed in carbonyl stretching modes.
• Catalysts exhibit tilt angles of 65-75° with carbonyl contact to the surface.
• Determined large interfacial electric fields (10^8-10^9 V/m) influencing the CO2 binding site.

Conclusions:

• Interfacial electric fields play a crucial role in the performance of molecular electrocatalysts.
• The study provides direct interpretation of catalyst configuration and field influence.