Bifunctional electrocatalysis for CO₂ reduction via surface capping-dependent metal-oxide interactions.

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Multi-component materials are crucial for advancing electrochemical CO2 reduction catalysts.
• Understanding complex catalyst interactions is key to unlocking improved reactivity.
• Metal-oxide interfaces play a significant role in catalytic performance.

Purpose of the Study:

• To investigate the impact of capping ligands on metal-oxide interactions in Au/SnO2 catalysts.
• To demonstrate ligand-dependent control over the selectivity of electrochemical CO2 reduction.
• To establish a method for tuning catalyst performance through surface modification.

Main Methods:

• Synthesis of Au/SnO2 catalysts with different capping ligands (CTAB, citrate, none).
• Electrochemical CO2 reduction experiments to assess product selectivity (CO, HCOO-, H2).
• Electrochemical CO oxidation as a probe reaction to study metal-oxide interactions.

Main Results:

• Cetyltrimethylammonium bromide (CTAB) capping on Au nanoparticles promotes bifunctional CO2 reduction, yielding CO and HCOO- at different potentials.
• Citrate capping or no capping on Au nanoparticles leads to Au-SnO2 interactions that favor H2 evolution.
• Electrochemical CO oxidation confirms that capping ligands significantly modulate metal-oxide interactions.

Conclusions:

• Capping ligands on gold nanoparticles are critical for controlling metal-oxide interactions in Au/SnO2 electrocatalysts.
• Ligand choice allows for tuning the selectivity of electrochemical CO2 reduction, enabling targeted product formation.
• This work provides a new strategy for designing advanced catalysts for CO2 conversion by managing interfacial chemistry.