Directed Structural Evolution of Nickel Nanoparticles into Atomically Dispersed Sites for Efficient CO₂...

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Electrochemical CO2 reduction (CO2RR) to CO is a promising carbon utilization strategy.
• Improving catalyst selectivity and activity for CO2RR remains a significant challenge.

Purpose of the Study:

• To develop and characterize a novel Ni/NC catalyst for enhanced CO2RR to CO.
• To investigate the structural evolution and active site dynamics of the catalyst during electrochemical activation.

Main Methods:

• Synthesis of Ni/NC catalyst via milling-pyrolysis.
• Electrochemical activation under Ar atmosphere.
• Characterization using XPS, AC-STEM, EXAFS, and in situ Raman spectroscopy.

Main Results:

• Electrochemical activation converted Ni particles into single-atom Ni sites (Ni-Nx).
• Achieved a current density of ~60 mA cm-2 with ~90% CO Faradaic efficiency at -0.8 V vs. RHE.
• Demonstrated accelerated charge transfer, favorable kinetics, and 24-hour operational stability.

Conclusions:

• The dynamic transformation of Ni active sites is crucial for high-performance CO2RR.
• The developed catalyst offers a promising route for efficient and selective CO2 to CO conversion.
• Provides insights for designing advanced transition metal catalysts for CO2 utilization.