A Self-Moderation Mechanism in CO₂ Electroreduction Catalyzed by a Cobalt Macrocyclic Complex

Area of Science:

• Electrochemistry
• Catalysis
• Materials Science

Background:

• Molecular electrocatalysts are crucial for sustainable energy solutions.
• Cobalt complexes show promise for carbon dioxide reduction.

Purpose of the Study:

• To investigate the mechanism of CO2 reduction by a tetra-aza-macrocyclic Schiff base cobalt complex.
• To understand the role of product binding in catalyst performance.

Main Methods:

• Operando UV-vis spectroelectrochemistry
• Cyclic voltammetry
• Rotating disk voltammetry
• Kinetic modeling

Main Results:

• The cobalt complex catalyzes CO2 to CO reduction in wet acetonitrile.
• A self-moderation mechanism was identified where CO reversibly binds to the active cobalt species.
• Product inhibition by CO was observed but did not lead to irreversible deactivation.

Conclusions:

• The [Co(N4H)(Cl)2]+ complex is a viable molecular platform for CO2 reduction.
• Reversible product binding offers a design principle for next-generation cobalt catalysts.
• Self-moderation influences catalytic efficiency and may facilitate subsequent CO activation.