A Planar, Conjugated N₄ -Macrocyclic Cobalt Complex for Heterogeneous Electrocatalytic CO₂ Reduction with High...

Area of Science:

• Electrochemistry
• Catalysis
• Materials Science

Background:

• Metal complexes are investigated as electrocatalysts for CO2 reduction.
• Current pyrrole-based ligands show limited activity.
• Developing efficient catalysts for CO2 conversion is crucial.

Purpose of the Study:

• To synthesize and evaluate a novel N4-macrocyclic cobalt complex for CO2 electrocatalysis.
• To compare its performance against existing metal complexes.
• To understand the electronic factors contributing to its catalytic activity.

Main Methods:

• Synthesis of a planar, conjugated N4-macrocyclic cobalt complex (Co(II)CPY) from phenanthroline subunits.
• Electrochemical testing in aqueous media to assess CO2 reduction to CO.
• Analysis of electronic structural features to elucidate catalytic mechanisms.

Main Results:

• Co(II)CPY demonstrates high activity and selectivity for CO2 electrocatalysis to CO.
• Achieved a Faradaic efficiency of 96% and a turnover frequency of 9.59 s⁻¹ at -0.70 V vs. RHE.
• Outperforms most previously reported metal complexes in CO2 reduction.

Conclusions:

• The novel Co(II)CPY complex is a highly efficient electrocatalyst for CO2 reduction.
• Synergistic effects between the ligand and cobalt enhance catalytic activity.
• Lowered free energy for *COOH formation contributes to improved CO production.