Single-Atom Engineering of Atomically Precise Ag-Cu Alloy Nanoclusters Enables Site-Gated Pathway Switching in CO₂...

Area of Science:

• Materials Science
• Nanotechnology
• Catalysis

Background:

• Atomically precise metal nanoclusters (NCs) are crucial for understanding structure-property relationships.
• Site-resolved single-atom engineering allows for precise control over NC properties.
• Silver-copper (Ag-Cu) alloy NCs offer a tunable platform for catalytic applications.

Purpose of the Study:

• To achieve site-resolved single-atom engineering on an Ag-Cu alloy NC platform.
• To investigate the impact of surface atomic identity on catalytic performance.
• To decouple the role of individual atomic sites in CO2 electroreduction.

Main Methods:

• Synthesis of Ag26Cu17 nanoclusters (NCs).
• Controlled metal-exchange reaction to sequentially replace surface Ag atoms with Cu.
• Electrospray ionization mass spectrometry for in situ tracking of substitution.
• Single-crystal X-ray diffraction for structural confirmation.
• Electrochemical CO2 reduction experiments to probe catalytic activity.

Main Results:

• Successful synthesis of an isostructural series of Ag-Cu NCs (Ag25Cu18, Ag24Cu19, Ag23Cu20) via single-atom substitution.
• Demonstrated retention of the cluster framework and ligand environment throughout the substitution process.
• Observed a switch in CO2 electroreduction pathway from CO selectivity (90.42% FE for CO) to deep reduction (73.00% total FE for deep products, 53.98% FE for CH4) with increasing Cu content.
• Attributed the pathway switch to modulated *CO stabilization and the *CO → *CHO energy barrier.

Conclusions:

• Established Ag-Cu NCs as a robust platform for site-resolved single-atom engineering.
• Confirmed the ability to precisely tune catalytic properties by controlling surface atomic composition.
• Highlighted the potential for atomic-scale structure-property analysis in catalysis.