Host-Guest Metal Interaction in Cu-In Single Atom Alloy Switching Electrocatalytic CO₂ Reduction Pathway

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Host-guest metal interactions critically influence alloy electrocatalyst behavior, affecting adsorption energies and product selectivity.
• Identifying active sites in conventional bimetallic alloys is challenging due to complex composition and structure.

Purpose of the Study:

• Investigate host-guest metal interactions in Cu-In single atom alloys (SAAs).
• Demonstrate pathway switching in electrochemical CO2 reduction reaction (CO2RR).
• Elucidate the role of Indium doping on Copper's active sites.

Main Methods:

• Synthesis and characterization of Cu-In SAAs with varying compositions.
• Electrochemical CO2RR performance evaluation.
• In situ spectroscopic measurements.
• Density Functional Theory (DFT) simulations.

Main Results:

• Doping 1% Indium into Cu matrix yielded isolated In-Cu interfaces, achieving >90% Faradaic efficiency for CO2-to-CO conversion.
• Doping 1% Cu into Indium matrix formed CuIn alloy, shifting selectivity to HCOOH with >90% Faradaic efficiency.
• DFT and in situ studies confirmed Cu as the active site, with Indium modulating CO2 adsorption and *CO binding.

Conclusions:

• Cu-In SAAs offer tunable CO2RR pathways through controlled host-guest interactions.
• Interface engineering at the atomic level is key to selective CO2 conversion.
• Understanding metal-metal interactions is crucial for designing advanced electrocatalysts.