Isolated copper-tin atomic interfaces tuning electrocatalytic CO₂ conversion.

Area of Science:

• Materials Science
• Catalysis
• Electrochemistry

Background:

• Direct experimental observation of interface structure is crucial for understanding heterogeneous catalysis.
• Designing interfaces using single-atom and surface science approaches is challenging but offers unique catalytic properties.

Purpose of the Study:

• To develop and investigate copper-tin (Cu-Sn) single-atom surface alloys for efficient electrocatalytic carbon dioxide (CO2) reduction.
• To understand the structure-activity relationship in Cu-Sn alloys for CO2 electroreduction.

Main Methods:

• Synthesis of Cu-Sn single-atom surface alloys with high surface densities of isolated Sn sites on a Cu host.
• Electrocatalytic testing in an alkaline flow cell to evaluate CO2 reduction performance.
• Density functional theory (DFT) simulations to elucidate the role of atomic structure and bonding.

Main Results:

• Cu-Sn surface alloys (Cu97Sn3 and Cu99Sn1) exhibited distinct catalytic selectivity compared to pure Cu and bulk Cu-Sn alloys.
• The Cu97Sn3 catalyst achieved 98% CO Faradaic efficiency at a low overpotential of 30 mV.
• A high CO current density of 100 mA cm-2 was obtained at 340 mV overpotential for Cu97Sn3.
• DFT simulations indicated that the local coordination environment of isolated Cu-Sn bonds is critical for reactivity.

Conclusions:

• Atomically dispersed Cu-Sn surface alloys are highly effective for electrocatalytic CO2 reduction.
• The specific geometric and electronic structure, particularly the Cu-Sn bonding, dictates catalytic performance.
• This work provides a pathway for designing advanced single-atom catalysts for CO2 conversion.