Spatially Matched C-N Coupling within Carbon Defect Confined Interlayer Fe Clusters for Efficient Urea...

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Urea electrosynthesis requires simultaneous CO2 and nitrate activation, a challenge for current catalysts.
• Designing spatially matched active sites for cooperative C-N coupling is crucial but difficult.

Purpose of the Study:

• To construct interlayer Fe atomic clusters (Feacs) within expanded 2H-graphitic carbon for enhanced urea electrosynthesis.
• To investigate the role of spatially matched nanoreactors in cooperative C-N coupling.

Main Methods:

• A carbon defect-confinement strategy was employed during pyrolysis under H2/Ar atmosphere.
• Kinetically modulated cascade reactions (FeO(x) reduction, carbon etching, vacancy trapping) were used.
• In-situ FTIR and DFT calculations were performed to understand reaction mechanisms.

Main Results:

• The interlayer Feacs catalyst achieved a high urea Faradaic efficiency of 39.80% and a normalized production rate of 3643.65 mm h-1 gFe-1.
• Performance was significantly higher (7.98- and 9.88-fold) compared to control samples.
• DFT and FTIR confirmed enhanced CO intermediate adsorption and lower energy barriers for key steps.

Conclusions:

• Spatially matched interlayer Feacs act as effective nanoreactors for cooperative C-N coupling in urea electrosynthesis.
• Carbon defects facilitate water dissociation and subsequent hydrogenation, promoting C-N coupling.
• This provides a new strategy for designing catalysts with matched active sites for sustainable urea synthesis.