Engineering Asymmetric Active Sites with Spin Polarization for Selective Photocatalytic CO₂-to-CH₃COOH Conversion

Area of Science:

• Materials Science
• Catalysis
• Electrochemistry

Background:

• Selective photocatalytic reduction of carbon dioxide (CO₂) to acetic acid (CH₃COOH) is crucial but limited by intermediate stabilization and C-C coupling.
• Existing catalysts often struggle with efficient charge separation and reaction kinetics.

Purpose of the Study:

• To develop a novel strategy for enhancing CO₂ reduction to CH₃COOH.
• To investigate the role of coordination environment engineering and spin polarization in catalytic activity.

Main Methods:

• Coordination-environment engineering by nitrogen incorporation into cobalt oxide (Co₃O₄) to create asymmetric cobalt active sites.
• Introduction of oxygen vacancies to further tune the electronic structure.
• Utilized in situ spectroscopy and theoretical calculations to analyze catalytic mechanisms.
• Investigated the effect of an external magnetic field on catalytic performance.

Main Results:

• Nitrogen substitution and oxygen vacancies created Co sites with distinct coordination and charge distributions, stabilizing *CO intermediates.
• Spin polarization enhanced charge carrier separation, with further intensification observed under an external magnetic field.
• The optimized N-Co₃O_4-x catalyst achieved a CH₃COOH yield of 41.4 μmol g^-1 h^-1 with 95% electron selectivity under magnetic field.

Conclusions:

• A dual-modulation strategy involving asymmetric active sites and spin polarization effectively facilitates CO₂-to-C₂ conversion.
• This approach offers a promising pathway for designing advanced catalysts for efficient carbon utilization.