Dramatic differences in carbon dioxide adsorption and initial steps of reduction between silver and copper.

Area of Science:

• Surface Science
• Catalysis
• Electrochemistry

Background:

• Converting carbon dioxide (CO2) to fuels is crucial.
• Lack of atomic-level understanding hinders catalyst development for CO2 electroreduction.

Purpose of the Study:

• To investigate the initial atomic-level events of CO2 electroreduction on silver (Ag) catalysts.
• To elucidate the reaction mechanism of CO2 and water (H2O) on Ag surfaces.

Main Methods:

• Ambient pressure X-ray photoelectron spectroscopy (AP-XPS).
• Quantum mechanics (QM) calculations.
• Combined experimental and computational approach.

Main Results:

• CO2 reacts with surface oxygen on Ag to form a chemisorbed O=CO2δ- species.
• Water molecules adsorb favorably onto the O=CO2δ- intermediate.
• A more favorable reaction pathway involving O=CO2δ- on Ag was identified compared to b-CO2 on copper (Cu).

Conclusions:

• The O=CO2δ- intermediate on Ag is key for efficient CO2 electroreduction.
• Understanding metal-surface interactions is vital for tuning CO2 adsorption and product selectivity.
• This study provides a basis for designing advanced catalysts for CO2 conversion.