Synergy between a Silver-Copper Surface Alloy Composition and Carbon Dioxide Adsorption and Activation

Area of Science:

• Materials Science
• Surface Chemistry
• Catalysis

Background:

• Bimetallic electrocatalysts offer enhanced selectivity for CO2 reduction reactions.
• Understanding the initial CO2 activation step on bimetallic surfaces is crucial but remains unclear.

Purpose of the Study:

• To investigate CO2 adsorption and activation mechanisms on silver-copper (AgCu) bimetallic surfaces.
• To elucidate the role of surface composition changes in CO2 activation.

Main Methods:

• Coupled ambient pressure X-ray photoelectron spectroscopy (APXPS) and quantum mechanics (QM) calculations.
• Density functional theory (DFT) was used to model CO2 adsorption and surface interactions.

Main Results:

• APXPS and DFT revealed a Ag-rich surface on clean AgCu.
• CO2 and surface oxygen adsorption promoted the substitution of surface Ag with subsurface Cu atoms.
• This Cu substitution altered the stability and activation of adsorbed CO2 species.

Conclusions:

• The study provides atomic-level insights into CO2 activation on AgCu surfaces.
• Surface reconstruction, specifically Cu substitution, is a key factor in tuning bimetallic catalyst performance for CO2 reduction.