Metal-π Sites Localized Hydrogen-*CO Coupling for Enhanced CO₂ Electromethanation.

Area of Science:

• Catalysis
• Electrochemistry
• Materials Science

Background:

• Electrochemical CO2 to CH4 conversion is crucial for sustainable energy.
• Existing Cu-N-C catalysts face limitations due to spatial mismatch of *H and *CO intermediates.
• This mismatch leads to side reactions like *H coupling and *CO dimerization, hindering CH4 formation.

Purpose of the Study:

• To design a catalyst that spatially matches *H and *CO for efficient CO2 to CH4 conversion.
• To investigate the role of inorganic-organic synergy in optimizing catalytic performance.
• To elucidate the reaction mechanism using advanced spectroscopic techniques.

Main Methods:

• Design and synthesis of a 2D metal-organic polymer catalyst with Cu-π units.
• Electrochemical CO2 reduction experiments at high current densities.
• Infrared free-electron laser (IRFEL) nanospectroscopy for in-situ characterization.
• Synchrotron radiation IR spectroscopy, electrochemical analysis, and theoretical calculations.

Main Results:

• The designed catalyst achieved a 61% Faradaic efficiency for CH4 production at 800 mA·cm-2.
• IRFEL nanospectroscopy identified the Cu-π coordination and bonding modes.
• π sites were found to adsorb hydrated cations, facilitating localized hydrogen supply.
• Suppression of long-range hydrogen transfer and side reactions was observed.

Conclusions:

• The inorganic-organic synergistic catalyst effectively matches *H and *CO intermediates.
• This strategy overcomes the spatial mismatch limitation in Cu-N-C catalysts.
• The findings offer a new pathway for efficient electrochemical CO2 to hydrocarbon conversion.