Molecular Inhibition for Selective CO₂ Conversion

Area of Science:

• Electrochemistry
• Catalysis
• Materials Science

Background:

• Electrochemical carbon dioxide (CO2) reduction is a promising sustainable method for producing valuable chemicals and fuels.
• Achieving high selectivity in CO2 reduction using heterogeneous copper (Cu) catalysts is difficult due to limited control over product distribution.
• Conventional modifications of catalyst materials provide insufficient control over reaction selectivity.

Purpose of the Study:

• To demonstrate that surface-immobilised molecular species can act as inhibitors to control product selectivity in electrochemical CO2 reduction.
• To provide a rational approach for modifying heterogeneous catalysts for enhanced selectivity.
• To investigate the mechanism by which molecular inhibitors influence CO2 reduction pathways.

Main Methods:

• Experimental investigation of surface-immobilised thiol-functionalised pyridine on copper (Cu) catalysts.
• Computational analysis using density functional theory (DFT) to study reaction intermediates and pathways.
• Characterisation of catalyst performance and product distribution under electrochemical conditions.

Main Results:

• Surface-immobilised pyridine derivatives were shown to selectively inhibit specific carbon product formation.
• Anchoring of a thiol-functionalised pyridine on Cu destabilised a key reaction intermediate, energetically blocking the carbon monoxide (CO) producing pathway.
• This inhibition mechanism significantly favoured the production of formate over CO.
• The nitrogen atom within the pyridine molecule was identified as essential for the observed inhibition effect.

Conclusions:

• Surface-immobilised molecules can serve as effective inhibitors, offering rational control over product selectivity in heterogeneous catalysis.
• This molecular inhibition strategy provides a novel approach to tailor catalyst performance for specific CO2 reduction products.
• The findings open new avenues for designing advanced catalysts for sustainable chemical synthesis via CO2 electroreduction.