Optimizing Electronic Microenvironment on Nickel Single-Atom Catalyst via In Situ Template Replacement for Efficient...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Optimizing metal-nitrogen-4 (M-N4) complexes is key for efficient electrochemical CO2 reduction (CO2RR).
• Tuning the coordination environment of metal centers influences reaction kinetics.

Purpose of the Study:

• To develop a facile strategy for regulating the atomic coordination microenvironment of nickel single-atom catalysts (Ni SACs).
• To synthesize Ni SACs with axial oxygen coordination at Ni-N4 sites for enhanced CO2RR performance.

Main Methods:

• In situ template replacement during one-pot pyrolysis.
• Synthesis of Ni SACs anchored on N, O-co-doped carbon nanosheet framework (Ni-N4O-C).
• Electrochemical characterization and mechanistic studies.

Main Results:

• Achieved outstanding performance in electrochemical CO2 to CO conversion with a maximum Faraday efficiency of 95%.
• Demonstrated remarkable durability, retaining over 90% efficiency after 90 hours of operation.
• Identified that oxygen coordination in Ni-N4O-C reduces the free energy barrier for *COOH intermediates.

Conclusions:

• Established a template-mediated coordination environment adjustment method for designing single-atom catalysts (SACs).
• The Ni-N4O-C catalyst shows significant potential for efficient and durable CO2RR.