A Dicationic fac-Re(bpy)(CO)₃Cl for CO₂ Electroreduction at a Reduced Overpotential

Area of Science:

• Inorganic Chemistry
• Electrochemistry
• Catalysis

Background:

• Rhenium bipyridine complexes are investigated for CO2 electroreduction.
• Tuning complex structure can influence catalytic activity and potential.
• Understanding reaction mechanisms is crucial for developing efficient catalysts.

Purpose of the Study:

• Synthesize and characterize a novel dicationic rhenium bipyridine complex.
• Investigate its electrochemical behavior for CO2 reduction.
• Elucidate the mechanism of electrocatalysis, focusing on the role of the dication.

Main Methods:

• Synthesis of the dicationic Re bipyridine complex.
• Electrochemical analysis using cyclic voltammetry.
• Spectroelectrochemistry (infrared) and theoretical calculations.
• Mechanistic studies under varying conditions (anhydrous, presence of acids).

Main Results:

• The synthesized complex exhibits electrocatalytic activity for CO2 reduction.
• The dicationic structure shifts the catalytic potential anodically.
• Coulombic stabilization of intermediates by the dication lowers the overpotential.
• CO is the major product, with formate observed in the presence of trifluoroethanol.

Conclusions:

• The dicationic rhenium complex is an effective electrocatalyst for CO2 reduction.
• The observed anodic shift and lowered potential are attributed to Coulombic stabilization.
• The study provides mechanistic insights into acid-assisted CO2 reduction pathways.