Activating dynamic atomic-configuration for single-site electrocatalyst in electrochemical CO₂ reduction.

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• High-efficiency electrocatalysts for CO2 electroreduction (CO2RR) require a deeper understanding of dynamic chemical states and atomic configurations under applied potentials.
• Copper single-atom electrocatalysts serve as a model system to investigate these complex evolutions.

Purpose of the Study:

• To elucidate the interplay between dynamic atomic configuration, chemical state changes, and surface charge during CO2 electroreduction.
• To identify key indicators for evaluating CO2RR performance and to discover active sites for efficient CO production.

Main Methods:

• Utilized a combination of in situ/operando techniques to monitor catalyst evolution during CO2 electroreduction.
• Employed copper single-atom electrocatalyst as a model system for detailed analysis.

Main Results:

• Demonstrated that dynamic atomic configuration, chemical state, and surface coulombic charging collectively dictate product profiles in CO2RR.
• Introduced atomic surface charge (φe) as a performance indicator and identified potential-driven dynamic low-coordinated Cu centers as highly selective for CO production.
• Observed partial reversibility in Cu-N bond breaking and irreversible Cu-Cu bond formation during structural reconstruction.
• Correlated high CO production efficiency with dynamic low-coordinated configurations across various single-atom electrocatalysts (Cu, Fe, Co).

Conclusions:

• Dynamic low-coordinated configurations are the active species for efficient CO2-to-CO conversion.
• Atomic surface charge (φe) serves as a universal indicator for CO2RR performance, linked to the formation of these active configurations.