Coordination Desymmetrization of Copper Single-Atom Catalyst for Efficient Nitrate Reduction.

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Single-atom catalysts (SACs) are crucial for optimizing catalytic performance.
• Copper SACs for nitrate reduction reactions (NO3RR) typically use symmetric Cu-N4 or Cu-N3 configurations.
• The mechanism of coordination environment regulation in SACs remains underexplored.

Purpose of the Study:

• To investigate the effect of coordination desymmetrization on copper SACs for NO3RR.
• To achieve efficient nitrate-to-ammonia conversion by disrupting symmetric coordination.
• To elucidate the correlation between coordination environment and catalytic properties.

Main Methods:

• Synthesis of Cu-N1O2 SACs with unsaturated heteroatomic coordination (Cu-O and Cu-N).
• Electrochemical evaluation of nitrate-to-ammonia conversion efficiency and yield rate.
• In situ Raman spectroscopy and theoretical calculations (surface dipole moment, orbital hybridization) to study the catalytic mechanism.

Main Results:

• Cu-N1O2 SACs demonstrated highly efficient nitrate-to-ammonia conversion.
• Achieved a Faradaic efficiency (FE) of ~96.5% and a yield rate of 3120 μg NH3 h-1 cm-2 at -0.60 V vs RHE.
• In situ Raman and theoretical studies revealed facilitated nitrate accumulation and selective nitrite adsorption.

Conclusions:

• Coordination desymmetrization of copper atoms in SACs significantly enhances NO3RR performance.
• The Cu-N1O2 structure promotes key intermediates adsorption, leading to high efficiency.
• This work establishes a clear link between coordination environment and catalytic activity in copper SACs for NO3RR.